Double click support

Looks like the max rate largely depends on end receiver quality - to improve to dynamically lower if queue fills up

.gitignore

@@ -4,3 +4,6 @@
 *.pio
 *.claude
 *.vscode
+web/version.js
+samples/
+firmware_dfu.zip

README.md

@@ -5,17 +5,17 @@ A BLE HID mouse that uses the onboard IMU of a **Seeed XIAO nRF52840 Sense** to
 ## Features
 
 - **6-DoF gyro + accelerometer** via LSM6DS3 with complementary filter
-- **Hardware tap detection** — single tap = left click, double tap = right click
-- **BLE HID mouse** — works natively on Windows, macOS, Linux, Android, iOS
-- **BLE Battery Service** — charge level visible in OS Bluetooth settings
-- **Web config UI** (`web/index.html`) — configure over BLE from any Chrome/Edge browser, no app install
-- **Flash persistence** — config survives power cycles (LittleFS)
-- **Live IMU stream** — 20 Hz gyro/accel data streamed to the web UI visualiser
-- **Live telemetry** — temperature, uptime, click counts, gyro bias RMS, recal count
-- **Temperature compensation** — gyro drift correction by Δ temperature since last calibration
-- **Auto-recalibration** — recalibrates automatically after 5 minutes of idle
-- **Configurable charge rate** — OFF / 50 mA slow / 100 mA fast via BQ25100 HICHG pin
-- **Boot-loop detection** — 3 rapid reboots trigger safe mode (config service disabled, flash wiped)
+- **Hardware tap detection** - single tap = left click, double tap = right click
+- **BLE HID mouse** - works natively on Windows, macOS, Linux, Android, iOS
+- **BLE Battery Service** - charge level visible in OS Bluetooth settings
+- **Web config UI** (`web/index.html`) - configure over BLE from any Chrome/Edge browser, no app install
+- **Flash persistence** - config survives power cycles (LittleFS)
+- **Live IMU stream** - 20 Hz gyro/accel data streamed to the web UI visualiser
+- **Live telemetry** - temperature, uptime, click counts, gyro bias RMS, recal count
+- **Temperature compensation** - gyro drift correction by Δ temperature since last calibration
+- **Auto-recalibration** - recalibrates automatically after 5 minutes of idle
+- **Configurable charge rate** - OFF / 50 mA slow / 100 mA fast via BQ25100 HICHG pin
+- **Boot-loop detection** - 3 rapid reboots trigger safe mode (config service disabled, flash wiped)
 
 ## Hardware
 
@@ -26,22 +26,22 @@ A BLE HID mouse that uses the onboard IMU of a **Seeed XIAO nRF52840 Sense** to
 
 ## LED Status
 
-The XIAO has three user LEDs (active LOW — HIGH = off, LOW = on):
+The XIAO has three user LEDs (active LOW - HIGH = off, LOW = on):
 
 | LED | Pattern | Meaning |
 |---|---|---|
 | Blue | Single pulse every 10 s | BLE connected (heartbeat) |
 | Green | Single pulse every 10 s | Advertising / not connected (heartbeat) |
 | Green | Rapid flutter (~10 Hz) | Gyro calibration in progress |
-| Red | Fast blink (continuous) | IMU init failed — hardware fault |
-| Red | 3 slow blinks on boot | Boot-loop detected — entered safe mode |
+| Red | Fast blink (continuous) | IMU init failed - hardware fault |
+| Red | 3 slow blinks on boot | Boot-loop detected - entered safe mode |
 | Red | 6 rapid blinks | Battery critically low (< 3.10 V) |
 
 > **Blue** = BLE-related state. **Green** = device activity. **Red** = fault only.
 
 ## Web Config UI
 
-Open `web/index.html` in Chrome or Edge (desktop). Requires Web Bluetooth — enable it at `chrome://flags/#enable-web-bluetooth` on Linux.
+Open `web/index.html` in Chrome or Edge (desktop). Requires Web Bluetooth - enable it at `chrome://flags/#enable-web-bluetooth` on Linux.
 
 **Configurable parameters:**
 
@@ -56,8 +56,8 @@ Open `web/index.html` in Chrome or Edge (desktop). Requires Web Bluetooth — en
 
 **Commands:**
 
-- **Calibrate Gyro** — recalculates bias offset; hold the device still on a flat surface for ~1 s
-- **Factory Reset** — wipes flash config, restores defaults
+- **Calibrate Gyro** - recalculates bias offset; hold the device still on a flat surface for ~1 s
+- **Factory Reset** - wipes flash config, restores defaults
 
 ## Building
 

model/pointer.FCMacro

@@ -1,283 +1,196 @@
-# IMU Pointer Enclosure
+"""
+IMU Pointer Enclosure — v11.7 (Slimmed Corners & Rounded USB-C)
+"""
 
 import FreeCAD as App
 import FreeCADGui as Gui
 import Part
 from FreeCAD import Base
 
-doc = App.newDocument("pointer")
+doc = App.newDocument("pointer_v11_7")
 
-# Global dimensions
-L = 115.0
-W = 36.0
-H = 20.0
+# ─── DIMENSIONS ───────────────────────────────────────────────────────────────
+L, W, H = 115.0, 36.0, 22.0
 WALL = 3.5
-CR = 3.0
+CR, CR_I = 8.0, 4.5
 TOL = 0.25 
+EDGE_FILLET = 3.0
 
-# Rail and lid
-RAIL_H = 4.5
-RAIL_D = 2.0
-LIP_H = 2.0
-LIP_OVER = 1.5
-LIP_EMBED = 0.2
+USBC_W, USBC_H, USBC_Z = 12.0, 7.0, 5.0 
+SPLIT_Z = USBC_Z + USBC_H + 2.5 
 
-LID_H = RAIL_H - LIP_H - TOL - 0.55
+# MICRO-DETENT Snap Logic
+TONGUE_H, TONGUE_T = 2.5, 2.0
+GROOVE_H, GROOVE_T = TONGUE_H + TOL, TONGUE_T + TOL
+RIDGE_W = 12.0
+RIDGE_H = 1.2      
+RIDGE_PROUD = 1.0  # Snap ridge protrusion
+RIDGE_Z_OFF = (TONGUE_H - RIDGE_H) / 2.0
 
-# Board dimensions
-PCB_T = 1.0
-BRD_L = 21.0
-BRD_W = 17.5
-BRD_X = WALL
-BRD_Y = (W - BRD_W) / 2
-
-PLATFORM_H = 0.5
+# ─── IMU BOARD (+1mm Spacing & Slim Corners) ──────────────────────────────────
+PCB_T, BRD_L, BRD_W = 3.0, 22.6, 19.6
+BRD_X, BRD_Y = WALL, (W - BRD_W) / 2.0
+PLATFORM_H, MIC_EXTRA = 1.5, 2.0
+MIC_PCB_T = 2.5          # Thicker PCB section (MEMS mic), rounded up from 2.2
+BUMP_PROUD = 0.3         # Press-fit nub protrusion into board cavity
+BUMP_R = 0.6             # Nub radius (half-sphere)
 BRD_Z = WALL + PLATFORM_H
 
-# Clip arms
-ARM_LEN = 5.0
-ARM_THICK = 1.6
-ARM_H = BRD_Z + PCB_T + 0.8
-CLIP_TOL = 0.35
-
-# USB-C cutout
-USBC_W = 11.0
-USBC_H = 7.0
-USBC_Z = 4.5
-
-# Battery section
-BAT_L = 50.0
-BAT_W = 12.0
-BAT_H = 12.0
-BAT_X = BRD_X + BRD_L + 8.0
-BAT_Y = (W - BAT_W) / 2
+# ─── BUTTON & BATTERY ─────────────────────────────────────────────────────────
+BAT_L, BAT_W, BAT_H = 50.0, 12.0, 12.0
+BAT_X, BAT_Y = BRD_X + BRD_L + 8.0 + 5.0, (W - BAT_W) / 2.0
 BAT_CLIP_Y = 8.0
+BTN_X, BTN_CY, BTN_HOLE_R = 28.0, W / 2.0, 10.0
+CAP_SHAFT_R, CAP_SHAFT_H = 9.6, WALL + 1.0   # +1mm taller shaft so cap sits flush
+CAP_RIM_R, CAP_RIM_H = 12.0, 1.5
+CAP_CAVITY_R, CAP_CAVITY_H = 5.2, 2.5        # Hollow cavity replaces nubbin — clears button dome
+BTN_DOME_R, BTN_DOME_SAG = 14.0, 0.6
 
+PCB_BOT_Z = SPLIT_Z + 1.5
+POST_H = BRD_Z + PCB_T + MIC_EXTRA + 3.0 - 4.0  # Lowered 4mm for button PCB + button thickness
+POST_OFFS_X, POST_OFFS_Y = 4.0, 11.0
+LH_R, LH_X, LH_Y_OFFS = 1.5, L - WALL - 3.0, 4.0
+BPCB_L, BPCB_W = 16.0, 16.0
 
-# Rounded box helper
-def rbox(lx, ly, lz, ox=0, oy=0, oz=0, r=CR):
-    b = Part.makeBox(lx, ly, lz, Base.Vector(ox, oy, oz))
-    try:
-        vert = [e for e in b.Edges
-                if abs(e.Vertexes[0].Z - e.Vertexes[1].Z) > lz * 0.9]
-        if vert:
-            b = b.makeFillet(r, vert)
-    except Exception:
-        pass
-    return b
+# ─── HELPERS ──────────────────────────────────────────────────────────────────
 
-
-# Simple box helper
 def box(lx, ly, lz, ox=0, oy=0, oz=0):
     return Part.makeBox(lx, ly, lz, Base.Vector(ox, oy, oz))
 
+def rbox(lx, ly, lz, ox=0, oy=0, oz=0, r=CR):
+    b = box(lx, ly, lz, ox, oy, oz)
+    try:
+        edges = [e for e in b.Edges if abs(e.Vertexes[0].X - e.Vertexes[1].X) < 1e-3 and abs(e.Vertexes[0].Y - e.Vertexes[1].Y) < 1e-3]
+        return b.makeFillet(r, edges) if edges else b
+    except: return b
 
-# Rounded slot helper
-def rounded_slot(depth, w, h, ox, oy, oz, r=None):
-    if r is None:
-        r = h / 2.0
+def cyl(r, h, cx=0, cy=0, cz=0):
+    return Part.makeCylinder(r, h, Base.Vector(cx, cy, cz))
 
-    r = min(r, h / 2.0, w / 2.0)
+def fillet_horiz(solid, r, z_test):
+    try:
+        edges = [e for e in solid.Edges if abs(e.Vertexes[0].Z - e.Vertexes[1].Z) < 0.2 and abs((e.Vertexes[0].Z + e.Vertexes[1].Z)/2 - z_test) < 1.5]
+        return solid.makeFillet(r, edges) if edges else solid
+    except: return solid
 
-    import math
+def make_slim_corner(cx, cy, ix, iy):
+    pw = 0.8  # Much slimmer wall thickness (was 1.5/1.6)
+    sl = 4.0  # Slightly shorter side length
+    h = PLATFORM_H + PCB_T + 0.5
     
-    cy = oy + w / 2.0
-    cz = oz + h / 2.0
-    hw = w / 2.0 - r
+    x0, y0 = (cx if ix>0 else cx-sl), (cy if iy>0 else cy-pw)
+    w1 = box(sl, pw, h, x0, y0, WALL)
     
-    def pt(cx, cy_v, cz_v, angle_deg, radius):
-        a = math.radians(angle_deg)
-        return Base.Vector(
-            cx,
-            cy_v + radius * math.cos(a),
-            cz_v + radius * math.sin(a)
-        )
+    x1, y1 = (cx if ix>0 else cx-pw), (cy if iy>0 else cy-sl)
+    w2 = box(pw, sl, h, x1, y1, WALL)
     
-    l_start = pt(ox, cy - hw, cz, 270, r)
-    l_mid = pt(ox, cy - hw, cz, 180, r)
-    l_end = pt(ox, cy - hw, cz, 90, r)
-    arc_left = Part.Arc(l_start, l_mid, l_end).toShape()
+    px, py = (cx if ix>0 else cx-sl), (cy if iy>0 else cy-sl)
+    plat = box(sl, sl, PLATFORM_H, px, py, WALL)
     
-    line_top = Part.makeLine(
-        l_end,
-        pt(ox, cy + hw, cz, 90, r)
-    )
+    return plat.fuse(w1).fuse(w2)
 
-    r_start = pt(ox, cy + hw, cz, 90, r)
-    r_mid = pt(ox, cy + hw, cz, 0, r)
-    r_end = pt(ox, cy + hw, cz, 270, r)
-    arc_right = Part.Arc(r_start, r_mid, r_end).toShape()
+# ═════════════════════════════════════════════════════════════════════════════
+#  CONSTRUCTION
+# ═════════════════════════════════════════════════════════════════════════════
 
-    line_bot = Part.makeLine(r_end, l_start)
+# BOTTOM SHELL
+bot_shell = fillet_horiz(rbox(L, W, SPLIT_Z + TONGUE_H), EDGE_FILLET, 0.0)
+bot_shell = bot_shell.cut(rbox(L-WALL*2, W-WALL*2, SPLIT_Z, WALL, WALL, WALL, r=CR_I))
+bot_shell = bot_shell.cut(rbox(L-TONGUE_T*2, W-TONGUE_T*2, TONGUE_H+2, TONGUE_T, TONGUE_T, SPLIT_Z, r=CR-TONGUE_T))
 
-    wire = Part.Wire([arc_left, line_top, arc_right, line_bot])
-    face = Part.Face(wire)
+# Internal Fusions (Using Slim L-bracket style for MCU)
+for cx, cy, ix, iy in [(BRD_X, BRD_Y, 1, 1), (BRD_X+BRD_L, BRD_Y, -1, 1), (BRD_X, BRD_Y+BRD_W, 1, -1), (BRD_X+BRD_L, BRD_Y+BRD_W, -1, -1)]:
+    bot_shell = bot_shell.fuse(make_slim_corner(cx, cy, ix, iy))
 
-    return face.extrude(Base.Vector(depth, 0, 0))
+# Press-fit nubs — half-sphere on each L-bracket's inner Y-facing wall (w1)
+bump_z = BRD_Z + 1.0 + BUMP_R           # Bottom of nub sits 1mm above platform
+pw = 0.8; sl = 4.0                      # Must match make_slim_corner
+for cx, cy, ix, iy in [(BRD_X, BRD_Y, 1, 1), (BRD_X+BRD_L, BRD_Y, -1, 1),
+                        (BRD_X, BRD_Y+BRD_W, 1, -1), (BRD_X+BRD_L, BRD_Y+BRD_W, -1, -1)]:
+    # w1 wall centre X: midpoint of the sl-long wall extending from corner
+    mid_x = cx + ix * sl / 2.0
+    # w1 inner face Y: the face that looks toward the board centre
+    face_y = cy if iy > 0 else cy - pw  # wall origin Y
+    inner_y = face_y + pw if iy > 0 else face_y  # the side facing inward
+    # iy>0 → bump faces +Y (inward), iy<0 → bump faces -Y (inward)
+    # Actually: iy>0 means corner is at low-Y side, wall inner face = face_y+pw, bump goes +Y
+    #           iy<0 means corner is at high-Y side, wall inner face = face_y, bump goes -Y
+    sph = Part.makeSphere(BUMP_R, Base.Vector(mid_x, inner_y, bump_z))
+    cs = BUMP_R + 0.5
+    # Clip: keep only the half protruding inward (toward board centre)
+    if iy > 0:
+        clip = box(cs*2, cs, cs*2, mid_x - cs, inner_y, bump_z - cs)
+    else:
+        clip = box(cs*2, cs, cs*2, mid_x - cs, inner_y - cs, bump_z - cs)
+    half_sph = sph.common(clip)
+    bot_shell = bot_shell.fuse(half_sph)
 
+POST_R = 1.75
+POST_TAPER_EXTRA = 0.3    # Extra radius at base
+POST_TAPER_H = 6.0        # Height over which the taper blends to nominal radius
+BACK_POST_SHIFT = POST_R  # Shift back posts by half a post diameter
+for ox in [-POST_OFFS_X, POST_OFFS_X]:
+  for oy in [-POST_OFFS_Y, POST_OFFS_Y]:
+    px = BTN_X + ox + (BACK_POST_SHIFT if ox > 0 else 0)
+    py = BTN_CY + oy
+    post = cyl(POST_R, POST_H, px, py, WALL)
+    # Tapered cone base: wider at bottom, blends to post radius at POST_TAPER_H
+    taper = Part.makeCone(POST_R + POST_TAPER_EXTRA, POST_R, POST_TAPER_H,
+                          Base.Vector(px, py, WALL))
+    post = post.fuse(taper)
+    post = post.cut(cyl(0.5, POST_H + 1, px, py, WALL))
+    bot_shell = bot_shell.fuse(post)
 
-# Board clip helper
-def make_clip(corner_x, corner_y, inward_x, inward_y):
+# Rounded USB-C Cut (Pill Shape)
+usbc_r = USBC_H / 2.0
+usbc_box = box(WALL*4, USBC_W - 2*usbc_r, USBC_H, -1, W/2 - USBC_W/2 + usbc_r, USBC_Z)
+usbc_cyl1 = Part.makeCylinder(usbc_r, WALL*4, Base.Vector(-1, W/2 - USBC_W/2 + usbc_r, USBC_Z + usbc_r), Base.Vector(1, 0, 0))
+usbc_cyl2 = Part.makeCylinder(usbc_r, WALL*4, Base.Vector(-1, W/2 + USBC_W/2 - usbc_r, USBC_Z + usbc_r), Base.Vector(1, 0, 0))
+usbc_rounded = usbc_box.fuse(usbc_cyl1).fuse(usbc_cyl2)
+bot_shell = bot_shell.cut(usbc_rounded)
 
-    plat_w = ARM_THICK + CLIP_TOL
+# Battery bay + retaining tabs
+bot_shell = bot_shell.cut(box(BAT_L, BAT_W, 3.0, BAT_X, BAT_Y, WALL))
+bat_clip_cy = BAT_Y + BAT_W / 2.0 - BAT_CLIP_Y / 2.0
+bot_shell = bot_shell.fuse(box(2.0, BAT_CLIP_Y, BAT_H * 0.55, BAT_X - 2.0,   bat_clip_cy, WALL))
+bot_shell = bot_shell.fuse(box(2.0, BAT_CLIP_Y, BAT_H * 0.55, BAT_X + BAT_L, bat_clip_cy, WALL))
 
-    plat_x = corner_x if inward_x > 0 else corner_x - plat_w
-    plat_y = corner_y if inward_y > 0 else corner_y - plat_w
+# MICRO-DETENT RIDGES: Buried deep, barely protruding
+rx0, rz0 = L/2 - RIDGE_W/2, SPLIT_Z + RIDGE_Z_OFF
+ridge_bury = 1.5 
+ridge_total_t = ridge_bury + RIDGE_PROUD
+bot_shell = bot_shell.fuse(box(RIDGE_W, ridge_total_t, RIDGE_H, rx0, TONGUE_T - ridge_bury, rz0))
+bot_shell = bot_shell.fuse(box(RIDGE_W, ridge_total_t, RIDGE_H, rx0, W - TONGUE_T - RIDGE_PROUD, rz0))
 
-    platform = box(
-        plat_w, plat_w,
-        PLATFORM_H + PCB_T,
-        plat_x, plat_y, WALL
-    )
+# TOP SHELL
+top_shell = fillet_horiz(rbox(L, W, H-SPLIT_Z, 0, 0, SPLIT_Z), EDGE_FILLET, H)
+top_shell = top_shell.cut(rbox(L-WALL*2, W-WALL*2, H-SPLIT_Z-WALL, WALL, WALL, SPLIT_Z, r=CR_I))
 
-    ax_ox = corner_x if inward_x > 0 else corner_x - ARM_LEN
-    ax_oy = corner_y - ARM_THICK - CLIP_TOL if inward_y > 0 else corner_y + CLIP_TOL
-    arm_x = box(ARM_LEN, ARM_THICK, ARM_H, ax_ox, ax_oy, WALL)
+# Groove and Matching Recesses
+g_band = rbox(L, W, GROOVE_H, 0, 0, SPLIT_Z, r=CR).cut(rbox(L-GROOVE_T*2, W-GROOVE_T*2, GROOVE_H+2, GROOVE_T, GROOVE_T, SPLIT_Z-1, r=CR-GROOVE_T))
+top_shell = top_shell.cut(g_band)
 
-    ay_oy = corner_y if inward_y > 0 else corner_y - ARM_LEN
-    ay_ox = corner_x - ARM_THICK - CLIP_TOL if inward_x > 0 else corner_x + CLIP_TOL
-    arm_y = box(ARM_THICK, ARM_LEN, ARM_H, ay_ox, ay_oy, WALL)
+# Recesses in groove wall — bottom ridges click into these
+rec_w = RIDGE_W + TOL*2
+rec_d = RIDGE_PROUD + TOL  # Slightly deeper than ridge protrusion
+top_shell = top_shell.cut(box(rec_w, rec_d, RIDGE_H+TOL, L/2-rec_w/2, GROOVE_T, rz0-TOL/2))
+top_shell = top_shell.cut(box(rec_w, rec_d, RIDGE_H+TOL, L/2-rec_w/2, W-GROOVE_T-rec_d, rz0-TOL/2))
 
-    corner_block_w = ARM_THICK + CLIP_TOL
-    cb_ox = corner_x - corner_block_w if inward_x > 0 else corner_x
-    cb_oy = corner_y - corner_block_w if inward_y > 0 else corner_y
+# Button & Cap
+top_shell = top_shell.cut(cyl(BTN_HOLE_R, H, BTN_X, BTN_CY, SPLIT_Z))
+top_shell = top_shell.cut(Part.makeSphere(BTN_DOME_R, Base.Vector(BTN_X, BTN_CY, H - WALL - BTN_DOME_R + BTN_DOME_SAG)))
+cap = cyl(CAP_SHAFT_R, CAP_SHAFT_H).fuse(cyl(CAP_RIM_R, CAP_RIM_H, 0, 0, -CAP_RIM_H))
+# Hollow cavity in bottom of shaft — button dome nests inside instead of a protruding nubbin
+cap = cap.cut(cyl(CAP_CAVITY_R, CAP_CAVITY_H, 0, 0, -CAP_RIM_H))
+cap_placed = cap.copy(); cap_placed.translate(Base.Vector(BTN_X, BTN_CY, H - CAP_SHAFT_H))
 
-    corner_block = box(
-        corner_block_w, corner_block_w, ARM_H,
-        cb_ox, cb_oy, WALL
-    )
-
-    return platform.fuse(arm_x.fuse(arm_y).fuse(corner_block))
-
-
-# Base outer body
-base = rbox(L, W, H)
-
-# Inner cavity
-base = base.cut(
-    box(L - WALL * 2, W - WALL * 2, H - WALL,
-        WALL, WALL, WALL)
-)
-
-rail_z = H - RAIL_H
-groove_h = RAIL_H - LIP_H
-
-# Rail grooves
-base = base.cut(
-    box(L - WALL * 2, RAIL_D, groove_h,
-        WALL, WALL - RAIL_D, rail_z)
-)
-
-base = base.cut(
-    box(L - WALL * 2, RAIL_D, groove_h,
-        WALL, W - WALL, rail_z)
-)
-
-# Lid lips
-lip_z = H - LIP_H
-
-base = base.fuse(
-    box(L - WALL * 2, LIP_OVER, LIP_H,
-        WALL, WALL, lip_z)
-)
-
-base = base.fuse(
-    box(L - WALL * 2, LIP_OVER, LIP_H,
-        WALL, W - WALL - LIP_OVER, lip_z)
-)
-
-# Back slot
-slot_y0 = WALL - RAIL_D
-slot_yw = W - WALL * 2 + RAIL_D * 2
-
-base = base.cut(
-    box(WALL + 1.0, slot_yw, RAIL_H,
-        L - WALL, slot_y0, rail_z)
-)
-
-# Entry bump
-BUMP_H = 0.5
-pad_raw = box(WALL, slot_yw, BUMP_H,
-              L - WALL, slot_y0, rail_z)
-
-pad_trimmed = pad_raw.common(rbox(L, W, H))
-base = base.fuse(pad_trimmed)
-
-# Board clips
-clip_corners = [
-    (BRD_X, BRD_Y, +1, +1),
-    (BRD_X + BRD_L, BRD_Y, -1, +1),
-    (BRD_X, BRD_Y + BRD_W, +1, -1),
-    (BRD_X + BRD_L, BRD_Y + BRD_W, -1, -1),
-]
-
-for cx, cy, ix, iy in clip_corners:
-    base = base.fuse(make_clip(cx, cy, ix, iy))
-
-# USB-C opening
-base = base.cut(
-    rounded_slot(
-        WALL * 3,
-        USBC_W,
-        USBC_H,
-        -WALL,
-        W / 2 - USBC_W / 2,
-        USBC_Z
-    )
-)
-
-# Battery recess
-base = base.cut(
-    box(BAT_L, BAT_W, 3.0,
-        BAT_X, BAT_Y, WALL)
-)
-
-clip_y_start = BAT_Y + BAT_W / 2 - BAT_CLIP_Y / 2
-
-base = base.fuse(
-    box(2.0, BAT_CLIP_Y, BAT_H * 0.55,
-        BAT_X - 2.0, clip_y_start, WALL)
-)
-
-base = base.fuse(
-    box(2.0, BAT_CLIP_Y, BAT_H * 0.55,
-        BAT_X + BAT_L, clip_y_start, WALL)
-)
-
-# Lid
-TAB_W = RAIL_D - TOL + 0.5
-LID_L = L - WALL * 2 - TOL
-LID_EXTRA_TOL = 0.5
-
-LID_W = (
-    W - WALL * 2
-    - (TOL + LID_EXTRA_TOL) * 2
-    + TAB_W * 2
-)
-
-lid_y0 = WALL + TOL + LID_EXTRA_TOL - TAB_W
-
-lid = box(LID_L, LID_W, LID_H, 0, lid_y0, 0)
-
-lid = lid.cut(
-    box(WALL * 2, USBC_W + TOL, LID_H + 0.2,
-        LID_L - WALL,
-        W / 2 - (USBC_W + TOL) / 2,
-        -0.1)
-)
-
-lid.translate(Base.Vector(WALL + TOL, 0, rail_z))
-
-# Final objects
-base_obj = doc.addObject("Part::Feature", "Pointer_Base")
-base_obj.Shape = base
-base_obj.ViewObject.ShapeColor = (0.12, 0.12, 0.14)
-
-lid_obj = doc.addObject("Part::Feature", "Pointer_Lid")
-lid_obj.Shape = lid
-lid_obj.ViewObject.ShapeColor = (0.28, 0.28, 0.34)
-lid_obj.ViewObject.Transparency = 25
+# ─── REGISTER ────────────────────────────────────────────────────────────────
+for name, shape, color in [("Shell_Bottom", bot_shell, (0.15, 0.15, 0.18)),
+                           ("Shell_Top", top_shell, (0.25, 0.25, 0.32)),
+                           ("Button_Cap", cap_placed, (0.7, 0.7, 0.7))]:
+    obj = doc.addObject("Part::Feature", name)
+    obj.Shape = shape
+    obj.ViewObject.ShapeColor = color
 
 doc.recompute()
-Gui.activeDocument().activeView().viewIsometric()
 Gui.SendMsgToActiveView("ViewFit")

platformio.ini

@@ -1,4 +1,4 @@
-; ── PlatformIO project configuration ─────────────────────────────────────────
+;  PlatformIO project configuration 
 ; Board  : Seeed XIAO nRF52840 Sense
 ; Core   : Adafruit nRF52 Arduino (via Seeed platform-seeedboards)
 ; Flash  : adafruit-nrfutil over USB serial (same as Arduino IDE)
@@ -6,7 +6,7 @@
 ; First-time setup:
 ;   pip install adafruit-nrfutil          <- upload tool (once, globally)
 ;   pio run -t upload                     <- build + flash
-; ──────────────────────────────────────────────────────────────────────────────
+; 
 
 [platformio]
 src_dir = source
@@ -16,7 +16,7 @@ platform  = https://github.com/Seeed-Studio/platform-seeedboards.git
 board     = seeed-xiao-afruitnrf52-nrf52840
 framework = arduino
 
-; ── Upload ────────────────────────────────────────────────────────────────────
+;  Upload 
 ; The XIAO uses a UF2 bootloader that accepts firmware via adafruit-nrfutil.
 ; Double-tap the reset button to enter bootloader (red LED pulses) before
 ; flashing if the board isn't auto-reset by the tool.
@@ -25,18 +25,23 @@ upload_speed    = 115200
 ; Uncomment and set the correct port if auto-detect fails:
 ; upload_port   = COM3
 
-; ── Build flags ───────────────────────────────────────────────────────────────
+;  Build scripts
+; git_hash.py  - injects short git hash into firmware + web/version.js
+; generate_dfu.py - generates firmware_dfu.zip for OTA upload (requires adafruit-nrfutil)
+extra_scripts = pre:scripts/git_hash.py, post:scripts/generate_dfu.py
+
+;  Build flags 
 build_flags =
     -DARDUINO_Seeed_XIAO_nRF52840_Sense
     -DNRF52840_XXAA
     -DTARGET_SEEED_XIAO_NRF52840_SENSE
 
-; ── Libraries ─────────────────────────────────────────────────────────────────
+;  Libraries 
 ; bluefruit.h, Adafruit_LittleFS.h, InternalFileSystem.h are bundled with
 ; the Adafruit nRF52 core and do NOT need to be listed here.
 ; Only external libraries are listed:
 lib_deps =
     Seeed-Studio/Seeed Arduino LSM6DS3 @ ^2.0.3
 
-; ── Serial monitor ────────────────────────────────────────────────────────────
+;  Serial monitor 
 monitor_speed = 115200

samples/double-clicking.csv

@@ -0,0 +1,111 @@
+ms,gyroX_mDPS,gyroZ_mDPS,accelX_mg,accelY_mg,accelZ_mg,moveX,moveY,flags
+53,2654,-3418,-1914,-2011,7816,1,0,0
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+10058,-2245,-1598,-1968,-1704,7420,0,0,0
+10148,-565,-1948,-1939,-1298,7191,0,0,0
+10253,-17785,6661,-2019,-1053,6933,0,0,8
+10359,3704,4981,-1727,-1169,8802,0,0,8
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+10853,-1615,-6848,-1354,-1528,7591,0,2,0
+10959,-845,-6638,-1054,-1491,7709,1,1,0

samples/normal-movement.csv

@@ -0,0 +1,101 @@
+ms,gyroX_mDPS,gyroZ_mDPS,accelX_mg,accelY_mg,accelZ_mg,moveX,moveY,flags
+22,-1615,-1388,490,-653,8088,0,0,1
+127,-3225,-20638,642,-1626,8062,0,0,8
+232,28134,3231,-4,-2987,9007,0,0,8
+337,23304,32000,-788,-2774,7141,0,0,8
+427,-27375,32000,-1389,-125,4358,0,0,8
+532,32000,32000,-813,1591,8309,0,0,8
+622,11614,32000,-1680,4802,9191,0,0,8
+727,-32000,-32000,-1584,1582,8091,0,0,8
+832,-32000,-32000,-1907,-4841,8164,0,0,8
+922,32000,-32000,-516,-4739,6249,0,0,8
+1027,-32000,32000,1036,-4463,9481,0,0,8
+1132,-32000,32000,1527,-4012,10133,0,0,8
+1222,32000,32000,431,-4558,10679,0,0,8
+1327,32000,7431,-395,-85,1273,0,0,8
+1432,32000,-32000,-2574,-1669,6583,0,0,8
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+9532,32000,-18398,2451,1601,15220,1,2,0
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+9922,32000,-32000,-888,-1647,7156,0,0,8

scripts/generate_dfu.py

@@ -0,0 +1,53 @@
+"""
+PlatformIO post-build script: generates a Nordic DFU package (.zip) from the
+built firmware .hex using adafruit-nrfutil.
+
+The resulting firmware_dfu.zip can be uploaded to the device via:
+  - nRF Connect mobile app (iOS / Android) after triggering OTA mode
+  - nRF Connect for Desktop
+  - adafruit-nrfutil over BLE (advanced)
+
+Trigger OTA mode on the device:
+  - Send BLE command 0x02 to cfgCommand (0x1236), OR
+  - Type 'o' in the serial monitor
+
+Usage: referenced from platformio.ini as:
+    extra_scripts = pre:scripts/git_hash.py, post:scripts/generate_dfu.py
+"""
+import subprocess, os
+
+Import("env")  # noqa: F821 - PlatformIO injects this
+
+def generate_dfu_package(source, target, env):
+    build_dir   = env.subst("$BUILD_DIR")
+    project_dir = env.subst("$PROJECT_DIR")
+    hex_path    = os.path.join(build_dir, "firmware.hex")
+
+    if not os.path.exists(hex_path):
+        print(f"[generate_dfu] firmware.hex not found at {hex_path}, skipping")
+        return
+
+    out_path = os.path.join(project_dir, "firmware_dfu.zip")
+
+    try:
+        result = subprocess.run(
+            [
+                "adafruit-nrfutil", "dfu", "genpkg",
+                "--dev-type", "0x0052",   # nRF52840
+                "--application", hex_path,
+                out_path,
+            ],
+            capture_output=True,
+            text=True,
+        )
+        if result.returncode == 0:
+            size_kb = os.path.getsize(out_path) / 1024
+            print(f"[generate_dfu] DFU package ready: firmware_dfu.zip ({size_kb:.1f} KB)")
+            print(f"[generate_dfu] Upload with nRF Connect after sending OTA command (0x02) via BLE")
+        else:
+            print(f"[generate_dfu] adafruit-nrfutil error: {result.stderr.strip()}")
+    except FileNotFoundError:
+        print("[generate_dfu] adafruit-nrfutil not found - skipping DFU package generation")
+        print("[generate_dfu] Install with: pip install adafruit-nrfutil")
+
+env.AddPostAction("$BUILD_DIR/firmware.hex", generate_dfu_package)  # noqa: F821

scripts/git_hash.py

@@ -0,0 +1,40 @@
+"""
+PlatformIO pre-build script: injects the short git commit hash into firmware
+as GIT_HASH (a C string literal), and writes web/version.js so the web UI
+can compare against it.
+
+Usage: referenced from platformio.ini as:
+    extra_scripts = pre:scripts/git_hash.py
+"""
+import subprocess, os, re
+
+Import("env")  # noqa: F821 - PlatformIO injects this
+
+def get_git_hash():
+    try:
+        h = subprocess.check_output(
+            ["git", "rev-parse", "--short=7", "HEAD"],
+            cwd=env.subst("$PROJECT_DIR"),    # noqa: F821
+            stderr=subprocess.DEVNULL,
+        ).decode().strip()
+        # Verify it looks like a hex hash (safety check)
+        if re.fullmatch(r"[0-9a-f]{4,12}", h):
+            return h
+    except Exception:
+        pass
+    return "unknown"
+
+git_hash = get_git_hash()
+print(f"[git_hash] short hash = {git_hash}")
+
+#  Inject into firmware build 
+env.Append(CPPDEFINES=[("GIT_HASH", f'\\"{git_hash}\\"')])  # noqa: F821
+
+#  Write web/version.js 
+web_dir  = os.path.join(env.subst("$PROJECT_DIR"), "web")  # noqa: F821
+ver_file = os.path.join(web_dir, "version.js")
+os.makedirs(web_dir, exist_ok=True)
+with open(ver_file, "w") as f:
+    f.write(f"// Auto-generated by scripts/git_hash.py - do not edit\n")
+    f.write(f"const FIRMWARE_BUILD_HASH = '{git_hash}';\n")
+print(f"[git_hash] wrote {ver_file}")

source/battery.cpp

@@ -13,14 +13,17 @@ void initBatteryADC() {
   pinMode(PIN_VBAT_ENABLE, OUTPUT); digitalWrite(PIN_VBAT_ENABLE, LOW);
   pinMode(PIN_VBAT_READ, INPUT);
   analogReference(AR_INTERNAL_3_0); analogReadResolution(12);
-  // Warm up with a few reads (no delay — just discard results)
+  // Warm up with a few reads (no delay - just discard results)
   for (int i=0; i<8; i++) analogRead(PIN_VBAT_READ);
 }
 
 float readBatteryVoltage() {
   // 8 quick reads, no delay() calls, no analogReference() change
   int32_t raw=0; for (int i=0; i<8; i++) raw += analogRead(PIN_VBAT_READ); raw /= 8;
-  return (raw / 4096.0f) * 3.0f * 2.0f;
+  // Seeed XIAO nRF52840 Sense: 1MΩ + 510kΩ voltage divider on VBAT.
+  // Theoretical ratio is 1510/510 = 2.961, but real resistor tolerances
+  // shift the actual ratio.  Calibrated: 3.90V actual / 3.78V reported → ×1.0317.
+  return (raw / 4096.0f) * 3.0f * (1510.0f / 510.0f) * 1.0317f;
 }
 
 int batteryPercent(float v) {
@@ -31,15 +34,20 @@ void updateBattery() {
   float v = readBatteryVoltage(); int pct = batteryPercent(v);
   bool chg = (digitalRead(PIN_CHG) == LOW);
   ChargeStatus status = chg ? (pct >= 99 ? CHGSTAT_FULL : CHGSTAT_CHARGING) : CHGSTAT_DISCHARGING;
-  blebas.write(pct);
+  // Only write BLE Battery Service when connected - blebas.write() blocks on the
+  // SoftDevice ATT layer and causes 30-40ms loop stalls when called during advertising.
+  if (Bluefruit.connected()) blebas.notify(pct);
   lastChargeStatus = status;
   #ifdef FEATURE_TELEMETRY
     telem.chargeStatus = (uint8_t)status;
   #endif
   const char* st[] = {"discharging","charging","full"};
   Serial.print("[BATT] "); Serial.print(v,2); Serial.print("V ");
-  Serial.print(pct); Serial.print("% "); Serial.println(st[status]);
-  if (status == CHGSTAT_DISCHARGING && v < BATT_CRITICAL)
+  Serial.print(pct); Serial.print("% "); Serial.print(st[status]);
+  Serial.print(" (PIN_CHG="); Serial.print(digitalRead(PIN_CHG)); Serial.println(")");
+  // Critical battery alert - only blink when not connected to avoid blocking BLE scheduler.
+  // 6 × 160ms = 960ms hard block; skip during active connection.
+  if (status == CHGSTAT_DISCHARGING && v < BATT_CRITICAL && !Bluefruit.connected())
     for (int i=0; i<6; i++) { digitalWrite(LED_RED,LOW); delay(80); digitalWrite(LED_RED,HIGH); delay(80); }
 }
 

source/ble_config.cpp

@@ -1,16 +1,23 @@
 #include "ble_config.h"
 #include "tap.h"
+#include "battery.h"
+#include "buttons.h"
 #include <Adafruit_LittleFS.h>
 #include <InternalFileSystem.h>
 
 using namespace Adafruit_LittleFS_Namespace;
 extern File cfgFile;
 
-// ─── BLE Config Service objects ───────────────────────────────────────────────
+// BLE Config Service objects 
+#ifndef GIT_HASH
+  #define GIT_HASH "unknown"
+#endif
+
 #ifdef FEATURE_CONFIG_SERVICE
 BLEService        cfgService   (0x1234);
 BLECharacteristic cfgBlob      (0x1235);  // ConfigBlob  R/W  20 bytes
 BLECharacteristic cfgCommand   (0x1236);  // Command       W   1 byte
+BLECharacteristic cfgGitHash   (0x1239);  // GitHash     R    8 bytes (7-char hash + NUL)
 #ifdef FEATURE_TELEMETRY
   BLECharacteristic cfgTelemetry(0x1237); // Telemetry   R/N  24 bytes
 #endif
@@ -19,18 +26,17 @@ BLECharacteristic cfgCommand   (0x1236);  // Command       W   1 byte
 #endif
 #endif
 
-// ─── Charge mode ──────────────────────────────────────────────────────────────
+// Charge mode
 void applyChargeMode(ChargeMode mode) {
   switch (mode) {
-    case CHARGE_OFF:  pinMode(PIN_HICHG, INPUT_PULLUP);                          break;
-    case CHARGE_SLOW: pinMode(PIN_HICHG, OUTPUT); digitalWrite(PIN_HICHG, HIGH); break;
+    case CHARGE_SLOW: pinMode(PIN_HICHG, INPUT);                                break;
     case CHARGE_FAST: pinMode(PIN_HICHG, OUTPUT); digitalWrite(PIN_HICHG, LOW); break;
   }
-  const char* n[] = {"OFF (~0mA)", "SLOW (50mA)", "FAST (100mA)"};
+  const char* n[] = {"SLOW (50mA)", "FAST (100mA)"};
   Serial.print("[CHG] "); Serial.println(n[mode]);
 }
 
-// ─── Config persistence ───────────────────────────────────────────────────────
+// Config persistence 
 void loadConfig() {
   InternalFS.begin();
   cfgFile.open(CONFIG_FILENAME, FILE_O_READ);
@@ -45,13 +51,16 @@ void loadConfig() {
 }
 
 void saveConfig() {
+  unsigned long t0 = millis();
   InternalFS.remove(CONFIG_FILENAME);
   cfgFile.open(CONFIG_FILENAME, FILE_O_WRITE);
-  if (cfgFile) { cfgFile.write((uint8_t*)&cfg, sizeof(cfg)); cfgFile.close(); Serial.println("[CFG] Saved"); }
-  else          { Serial.println("[CFG] ERROR: write failed"); }
+  if (cfgFile) { cfgFile.write((uint8_t*)&cfg, sizeof(cfg)); cfgFile.close(); }
+  unsigned long elapsed = millis() - t0;
+  if (elapsed > 5) { Serial.print("[CFG] Saved ("); Serial.print(elapsed); Serial.println("ms - flash block)"); }
+  else               { Serial.println("[CFG] Saved"); }
 }
 
-// ─── ConfigBlob push ─────────────────────────────────────────────────────────
+// ConfigBlob push 
 #ifdef FEATURE_CONFIG_SERVICE
 void pushConfigBlob() {
   ConfigBlob b;
@@ -65,7 +74,9 @@ void pushConfigBlob() {
   b.tapAction     = (uint8_t)cfg.tapAction;
   b.tapKey           = cfg.tapKey;
   b.tapMod           = cfg.tapMod;
-  b._pad          = 0;
+  b.tapFreezeEnabled = cfg.tapFreezeEnabled;
+  b.jerkThreshold    = cfg.jerkThreshold;
+  b.featureFlags     = cfg.featureFlags;
   cfgBlob.write((uint8_t*)&b, sizeof(b));
 }
 #endif
@@ -88,7 +99,7 @@ void factoryReset() {
   Serial.println("[CFG] Factory reset complete");
 }
 
-// ─── BLE callbacks ────────────────────────────────────────────────────────────
+// BLE callbacks 
 #ifdef FEATURE_CONFIG_SERVICE
 void onConfigBlobWrite(uint16_t h, BLECharacteristic* c, uint8_t* d, uint16_t l) {
   if (l != sizeof(ConfigBlob)) { Serial.println("[CFG] Bad blob length"); return; }
@@ -98,7 +109,7 @@ void onConfigBlobWrite(uint16_t h, BLECharacteristic* c, uint8_t* d, uint16_t l)
   cfg.accelStrength = b->accelStrength;
   if (b->curve     <= 2) cfg.curve = (CurveType)b->curve;
   cfg.axisFlip = b->axisFlip;
-  if (b->chargeMode <= 2) { cfg.chargeMode = (ChargeMode)b->chargeMode; applyChargeMode(cfg.chargeMode); }
+  if (b->chargeMode <= 1) { cfg.chargeMode = (ChargeMode)b->chargeMode; applyChargeMode(cfg.chargeMode); }
   #ifdef FEATURE_TAP_DETECTION
     if (b->tapThreshold >= 1 && b->tapThreshold <= 31) {
       cfg.tapThreshold = b->tapThreshold;
@@ -108,8 +119,11 @@ void onConfigBlobWrite(uint16_t h, BLECharacteristic* c, uint8_t* d, uint16_t l)
     cfg.tapKey = b->tapKey;
     cfg.tapMod = b->tapMod;
   #endif
+  cfg.tapFreezeEnabled = b->tapFreezeEnabled ? 1 : 0;
+  if (b->jerkThreshold >= 100.0f && b->jerkThreshold <= 50000.0f) cfg.jerkThreshold = b->jerkThreshold;
+  cfg.featureFlags = b->featureFlags & (FLAG_TAP_ENABLED | FLAG_TEMP_COMP_ENABLED | FLAG_AUTO_RECAL_ENABLED);
   saveConfig();
-  Serial.print("[CFG] Written — sens="); Serial.print(cfg.sensitivity,0);
+  Serial.print("[CFG] Written - sens="); Serial.print(cfg.sensitivity,0);
   Serial.print(" dz="); Serial.print(cfg.deadZone,3);
   Serial.print(" tapThr="); Serial.print(cfg.tapThreshold);
   Serial.print(" tapAction="); Serial.println(cfg.tapAction);
@@ -119,6 +133,9 @@ void onCommandWrite(uint16_t h, BLECharacteristic* c, uint8_t* d, uint16_t l) {
   if (l < 1) return;
   if (d[0] == 0x01) pendingCal   = true;
   if (d[0] == 0xFF) pendingReset = true;
+  #ifdef FEATURE_OTA
+    if (d[0] == 0x02) pendingOTA = true;
+  #endif
 }
 
 #ifdef FEATURE_IMU_STREAM
@@ -128,7 +145,7 @@ void onImuStreamCccd(uint16_t conn_hdl, BLECharacteristic* chr, uint16_t value)
 }
 #endif
 
-// ─── BLE config service setup ─────────────────────────────────────────────────
+// BLE config service setup 
 void setupConfigService() {
   cfgService.begin();
 
@@ -139,12 +156,20 @@ void setupConfigService() {
   cfgBlob.begin();
   pushConfigBlob();
 
-  cfgCommand.setProperties(CHR_PROPS_WRITE);
+  cfgCommand.setProperties(CHR_PROPS_WRITE | CHR_PROPS_WRITE_WO_RESP);
   cfgCommand.setPermission(SECMODE_OPEN, SECMODE_OPEN);
   cfgCommand.setFixedLen(1);
   cfgCommand.setWriteCallback(onCommandWrite);
   cfgCommand.begin();
 
+  // Git hash - 8-byte fixed field (7 hex chars + NUL), read-only
+  cfgGitHash.setProperties(CHR_PROPS_READ);
+  cfgGitHash.setPermission(SECMODE_OPEN, SECMODE_NO_ACCESS);
+  cfgGitHash.setFixedLen(8);
+  cfgGitHash.begin();
+  { uint8_t buf[8] = {}; strncpy((char*)buf, GIT_HASH, 7); cfgGitHash.write(buf, 8); }
+  Serial.print("[BUILD] git="); Serial.println(GIT_HASH);
+
   #ifdef FEATURE_TELEMETRY
     cfgTelemetry.setProperties(CHR_PROPS_READ | CHR_PROPS_NOTIFY);
     cfgTelemetry.setPermission(SECMODE_OPEN, SECMODE_NO_ACCESS);
@@ -173,7 +198,7 @@ void setupConfigService() {
 }
 #endif // FEATURE_CONFIG_SERVICE
 
-// ─── Telemetry push ───────────────────────────────────────────────────────────
+// Telemetry push 
 #ifdef FEATURE_TELEMETRY
 void pushTelemetry(unsigned long now) {
   telem.uptimeSeconds = now / 1000;
@@ -184,6 +209,9 @@ void pushTelemetry(unsigned long now) {
     telem.leftClicks  = statLeftClicks;
     telem.rightClicks = statRightClicks;
   #endif
+  #ifdef FEATURE_BATTERY_MONITOR
+    telem.battVoltage = readBatteryVoltage();
+  #endif
   cfgTelemetry.write ((uint8_t*)&telem, sizeof(telem));
   cfgTelemetry.notify((uint8_t*)&telem, sizeof(telem));
 }

source/ble_config.h

@@ -7,6 +7,7 @@
 extern BLEService        cfgService;
 extern BLECharacteristic cfgBlob;
 extern BLECharacteristic cfgCommand;
+extern BLECharacteristic cfgGitHash;
 #ifdef FEATURE_TELEMETRY
   extern BLECharacteristic cfgTelemetry;
 #endif

source/buttons.cpp

@@ -0,0 +1,96 @@
+#include "buttons.h"
+
+#ifdef FEATURE_PHYSICAL_BUTTONS
+#include <bluefruit.h>
+
+extern BLEHidAdafruit blehid;
+extern Config cfg;
+
+static uint8_t physBtnMask = 0;
+static uint8_t rawMaskPrev = 0;
+static unsigned long debounceMs = 0;
+static const unsigned long DEBOUNCE_MS = 20;
+
+// Double-press detection for left button
+static const unsigned long DOUBLE_PRESS_MS = 400;   // max gap between two releases
+static const unsigned long KEY_HOLD_MS     = 60;    // how long to hold the key down
+static unsigned long lastLeftReleaseMs = 0;
+static unsigned long keyDownUntil      = 0;
+
+// Setup 
+void setupPhysicalButtons() {
+  // Release any held physical buttons before reconfiguring
+  if (physBtnMask && Bluefruit.connected()) { blehid.mouseButtonRelease(); }
+  physBtnMask = 0;
+
+  if (BTN_LEFT_PIN   != BTN_PIN_NONE) pinMode(BTN_LEFT_PIN,   INPUT_PULLUP);
+  if (BTN_RIGHT_PIN  != BTN_PIN_NONE) pinMode(BTN_RIGHT_PIN,  INPUT_PULLUP);
+  if (BTN_MIDDLE_PIN != BTN_PIN_NONE) pinMode(BTN_MIDDLE_PIN, INPUT_PULLUP);
+
+  bool any = (BTN_LEFT_PIN != BTN_PIN_NONE) || (BTN_RIGHT_PIN != BTN_PIN_NONE)
+          || (BTN_MIDDLE_PIN != BTN_PIN_NONE);
+  if (any) {
+    Serial.print("[BTN] L=");
+    BTN_LEFT_PIN   == BTN_PIN_NONE ? Serial.print("--") : Serial.print(BTN_LEFT_PIN);
+    Serial.print(" R=");
+    BTN_RIGHT_PIN  == BTN_PIN_NONE ? Serial.print("--") : Serial.print(BTN_RIGHT_PIN);
+    Serial.print(" M=");
+    BTN_MIDDLE_PIN == BTN_PIN_NONE ? Serial.print("--") : Serial.print(BTN_MIDDLE_PIN);
+    Serial.println();
+  }
+}
+
+// Poll and report 
+// Called every loop iteration (before rate limiter) for immediate response.
+// Uses active-low logic: INPUT_PULLUP, button connects pin to GND.
+void processPhysicalButtons() {
+  if (!Bluefruit.connected()) return;
+
+  unsigned long now = millis();
+
+  // Release held key combo after KEY_HOLD_MS
+  if (keyDownUntil && now >= keyDownUntil) {
+    uint8_t noKeys[6] = {};
+    blehid.keyboardReport(0, noKeys);
+    keyDownUntil = 0;
+    Serial.println("[BTN] key release");
+  }
+
+  uint8_t rawMask = 0;
+  if (BTN_LEFT_PIN   != BTN_PIN_NONE && digitalRead(BTN_LEFT_PIN)   == LOW) rawMask |= MOUSE_BUTTON_LEFT;
+  if (BTN_RIGHT_PIN  != BTN_PIN_NONE && digitalRead(BTN_RIGHT_PIN)  == LOW) rawMask |= MOUSE_BUTTON_RIGHT;
+  if (BTN_MIDDLE_PIN != BTN_PIN_NONE && digitalRead(BTN_MIDDLE_PIN) == LOW) rawMask |= MOUSE_BUTTON_MIDDLE;
+
+  if (rawMask != rawMaskPrev) { rawMaskPrev = rawMask; debounceMs = now; }
+  if (rawMask != physBtnMask && (now - debounceMs >= DEBOUNCE_MS)) {
+    uint8_t newMask = rawMask;
+    uint8_t pressed  = newMask & ~physBtnMask;
+    uint8_t released = physBtnMask & ~newMask;
+    physBtnMask = newMask;
+    if (physBtnMask) blehid.mouseButtonPress(physBtnMask);
+    else             blehid.mouseButtonRelease();
+    if (pressed & MOUSE_BUTTON_LEFT)    Serial.println("[BTN] L press");
+    if (pressed & MOUSE_BUTTON_RIGHT)   Serial.println("[BTN] R press");
+    if (pressed & MOUSE_BUTTON_MIDDLE)  Serial.println("[BTN] M press");
+    if (released & MOUSE_BUTTON_LEFT) {
+      unsigned long gap = lastLeftReleaseMs ? (now - lastLeftReleaseMs) : 0;
+      Serial.print("[BTN] L release - gap="); Serial.print(gap);
+      Serial.print("ms (max="); Serial.print(DOUBLE_PRESS_MS); Serial.println("ms)");
+      // Double-press detection: two short presses → fire key combo
+      if (lastLeftReleaseMs && (gap <= DOUBLE_PRESS_MS)) {
+        uint8_t keys[6] = {cfg.tapKey, 0, 0, 0, 0, 0};
+        blehid.keyboardReport(cfg.tapMod, keys);
+        keyDownUntil = now + KEY_HOLD_MS;
+        lastLeftReleaseMs = 0;
+        Serial.print("[BTN] Double-press → key 0x"); Serial.print(cfg.tapKey, HEX);
+        Serial.print(" mod 0x"); Serial.println(cfg.tapMod, HEX);
+      } else {
+        lastLeftReleaseMs = now;
+      }
+    }
+    if (released & MOUSE_BUTTON_RIGHT)  Serial.println("[BTN] R release");
+    if (released & MOUSE_BUTTON_MIDDLE) Serial.println("[BTN] M release");
+  }
+}
+
+#endif // FEATURE_PHYSICAL_BUTTONS

source/buttons.h

@@ -0,0 +1,7 @@
+#pragma once
+#include "config.h"
+
+#ifdef FEATURE_PHYSICAL_BUTTONS
+void setupPhysicalButtons();
+void processPhysicalButtons();
+#endif

source/config.h

@@ -1,23 +1,25 @@
 #pragma once
 #include <Arduino.h>
 
-// ─── Feature Flags ────────────────────────────────────────────────────────────
+// Feature Flags 
 #define FEATURE_CONFIG_SERVICE
 #define FEATURE_TELEMETRY
 #define FEATURE_IMU_STREAM
-#define FEATURE_TAP_DETECTION
+// #define FEATURE_TAP_DETECTION
 #define FEATURE_TEMP_COMPENSATION
 #define FEATURE_AUTO_RECAL
 #define FEATURE_BATTERY_MONITOR
 #define FEATURE_BOOT_LOOP_DETECT
+#define FEATURE_PHYSICAL_BUTTONS
+#define FEATURE_OTA
 
-// ─── Debug ────────────────────────────────────────────────────────────────────
+// Debug 
 // #define DEBUG
 
-// ─── ATT table size ───────────────────────────────────────────────────────────
+// ATT table size 
 #define _ATT_BASE 900
 #ifdef FEATURE_CONFIG_SERVICE
-  #define _ATT_CFG 80
+  #define _ATT_CFG 100   // +20 for cfgGitHash characteristic
 #else
   #define _ATT_CFG 0
 #endif
@@ -34,7 +36,7 @@
 #define ATT_TABLE_SIZE_CALC (_ATT_BASE + _ATT_CFG + _ATT_TELEM + _ATT_STREAM)
 #define ATT_TABLE_SIZE (ATT_TABLE_SIZE_CALC < 1536 ? 1536 : ATT_TABLE_SIZE_CALC)
 
-// ─── IMU register addresses ───────────────────────────────────────────────────
+// IMU register addresses 
 #define REG_CTRL1_XL    0x10
 #define REG_TAP_CFG     0x58
 #define REG_TAP_THS_6D  0x59
@@ -45,22 +47,37 @@
 #define REG_OUT_TEMP_L  0x20
 #define REG_OUT_TEMP_H  0x21
 
-// ─── Pins ─────────────────────────────────────────────────────────────────────
+// Pins 
 #define PIN_VBAT_ENABLE (14)
 #define PIN_VBAT_READ   (32)
 #define PIN_CHG         (23)
 #define PIN_HICHG       (22)
 
-// ─── Persistence ──────────────────────────────────────────────────────────────
+// Persistence 
 #define CONFIG_FILENAME  "/imu_mouse_cfg.bin"
-#define CONFIG_MAGIC     0xDEAD1239UL
+#define CONFIG_MAGIC     0xDEAD123EUL
 
-// ─── Enums ────────────────────────────────────────────────────────────────────
+// Physical button pin assignments (hardcoded - set to 0xFF to disable a button)
+// Valid pin numbers: 0-10 (Arduino D0-D10 on XIAO nRF52840 Sense)
+#define BTN_PIN_NONE   0xFF
+#define BTN_LEFT_PIN   1              // D1, active-low to GND
+#define BTN_RIGHT_PIN  BTN_PIN_NONE   // e.g. 1 for D1
+#define BTN_MIDDLE_PIN BTN_PIN_NONE   // e.g. 2 for D2
+
+// Runtime feature-override flags (cfg.featureFlags bitmask) 
+// These mirror the compile-time FEATURE_* defines but can be toggled at runtime
+// via the web UI and persisted in flash.  Bits not listed here are reserved = 0.
+#define FLAG_TAP_ENABLED        0x01  // Tap detection active (requires restart)
+#define FLAG_TEMP_COMP_ENABLED  0x02  // Temperature gyro-drift compensation
+#define FLAG_AUTO_RECAL_ENABLED 0x04  // Auto-recalibrate after long idle
+#define FLAG_ALL_DEFAULT        (FLAG_TAP_ENABLED | FLAG_TEMP_COMP_ENABLED | FLAG_AUTO_RECAL_ENABLED)
+
+// Enums 
 enum CurveType   : uint8_t { CURVE_LINEAR=0, CURVE_SQUARE=1, CURVE_SQRT=2 };
-enum ChargeMode  : uint8_t { CHARGE_OFF=0,   CHARGE_SLOW=1,  CHARGE_FAST=2 };
+enum ChargeMode  : uint8_t { CHARGE_SLOW=0, CHARGE_FAST=1 };
 enum ChargeStatus: uint8_t { CHGSTAT_DISCHARGING=0, CHGSTAT_CHARGING=1, CHGSTAT_FULL=2 };
 
-// ─── Tap action types ─────────────────────────────────────────────────────────
+// Tap action types 
 // TAP_ACTION_KEY: fires a raw HID keycode (tapKey) with optional modifier (tapMod).
 // Modifier byte: bit0=Ctrl, bit1=Shift, bit2=Alt, bit3=GUI (same as HID modifier byte).
 enum TapAction : uint8_t {
@@ -70,7 +87,7 @@ enum TapAction : uint8_t {
   TAP_ACTION_KEY    = 3,
 };
 
-// ─── Config (stored in flash) ─────────────────────────────────────────────────
+// Config (stored in flash) 
 struct Config {
   uint32_t   magic;
   float      sensitivity;
@@ -83,11 +100,14 @@ struct Config {
   TapAction  tapAction;    // what a double-tap does
   uint8_t    tapKey;       // HID keycode (used when tapAction == TAP_ACTION_KEY)
   uint8_t    tapMod;       // HID modifier byte (used when tapAction == TAP_ACTION_KEY)
+  float      jerkThreshold;    // jerk² threshold for tap-freeze detection
+  uint8_t    tapFreezeEnabled; // 1 = enable jerk-based cursor freeze during taps
+  uint8_t    featureFlags;     // bitmask of FLAG_* - runtime feature overrides
 };
 extern Config cfg;
 extern const Config CFG_DEFAULTS;
 
-// ─── ConfigBlob (over BLE, 20 bytes) ─────────────────────────────────────────
+// ConfigBlob (over BLE, 25 bytes) 
 struct __attribute__((packed)) ConfigBlob {
   float   sensitivity;       // [0]
   float   deadZone;          // [4]
@@ -99,11 +119,13 @@ struct __attribute__((packed)) ConfigBlob {
   uint8_t tapAction;         // [16]  TapAction enum
   uint8_t tapKey;            // [17]  HID keycode
   uint8_t tapMod;            // [18]  HID modifier
-  uint8_t _pad;           // [19]
+  uint8_t tapFreezeEnabled;  // [19]  1 = enable jerk-based cursor freeze during taps
+  float   jerkThreshold;     // [20]  jerk² tap-freeze threshold
+  uint8_t featureFlags;      // [24]  FLAG_* bitmask - runtime feature overrides
 };
-static_assert(sizeof(ConfigBlob) == 20, "ConfigBlob must be 20 bytes");
+static_assert(sizeof(ConfigBlob) == 25, "ConfigBlob must be 25 bytes");
 
-// ─── TelemetryPacket (24 bytes) ───────────────────────────────────────────────
+// TelemetryPacket (24 bytes) 
 #ifdef FEATURE_TELEMETRY
 struct __attribute__((packed)) TelemetryPacket {
   uint32_t uptimeSeconds;   // [0]
@@ -114,16 +136,17 @@ struct __attribute__((packed)) TelemetryPacket {
   uint16_t recalCount;      // [20]
   uint8_t  chargeStatus;    // [22]
   uint8_t  _pad;            // [23]
+  float    battVoltage;     // [24]  raw battery voltage (V)
 };
-static_assert(sizeof(TelemetryPacket) == 24, "TelemetryPacket must be 24 bytes");
+static_assert(sizeof(TelemetryPacket) == 28, "TelemetryPacket must be 28 bytes");
 extern TelemetryPacket telem;
 #endif
 
-// ─── ImuPacket (14 bytes) ─────────────────────────────────────────────────────
+// ImuPacket (14 bytes) 
 #ifdef FEATURE_IMU_STREAM
 struct __attribute__((packed)) ImuPacket {
-  int16_t  gyroY_mDPS;  // [0]
-  int16_t  gyroZ_mDPS;  // [2]
+  int16_t  gyroX_mDPS;  // [0]  pitch axis (nod up/down → cursor Y)
+  int16_t  gyroZ_mDPS;  // [2]  yaw axis   (pan left/right → cursor X)
   int16_t  accelX_mg;   // [4]
   int16_t  accelY_mg;   // [6]
   int16_t  accelZ_mg;   // [8]
@@ -135,8 +158,7 @@ struct __attribute__((packed)) ImuPacket {
 static_assert(sizeof(ImuPacket) == 14, "ImuPacket must be 14 bytes");
 #endif
 
-// ─── Tuning constants ─────────────────────────────────────────────────────────
-extern const float ALPHA;
+// Tuning constants
 extern const int   LOOP_RATE_MS;
 extern const int   BIAS_SAMPLES;
 extern const int   IDLE_FRAMES;
@@ -161,8 +183,7 @@ extern const float BATT_CRITICAL;
   extern const unsigned long AUTO_RECAL_MS;
 #endif
 
-// ─── Global state ─────────────────────────────────────────────────────────────
-extern float angleX, angleY;
+// Global state
 extern float accumX, accumY;
 extern float biasGX, biasGY, biasGZ;
 extern float calTempC;
@@ -182,6 +203,9 @@ extern float cachedTempC;
 
 extern bool pendingCal;
 extern bool pendingReset;
+#ifdef FEATURE_OTA
+  extern bool pendingOTA;
+#endif
 extern ChargeStatus lastChargeStatus;
 extern int           idleFrames;
 extern unsigned long idleStartMs;

source/imu.cpp

@@ -1,9 +1,10 @@
 #include "imu.h"
 #include "Wire.h"
+#include <math.h>
 
 LSM6DS3 imu(I2C_MODE, 0x6A);
 
-// ─── I2C helpers ──────────────────────────────────────────────────────────────
+// I2C helpers 
 void imuWriteReg(uint8_t reg, uint8_t val) {
   // LSM6DS3 is on Wire1 (internal I2C, SDA=P0.17, SCL=P0.16), NOT Wire (external pins 4/5)
   Wire1.beginTransmission(0x6A); Wire1.write(reg); Wire1.write(val); Wire1.endTransmission();
@@ -15,13 +16,13 @@ uint8_t imuReadReg(uint8_t reg) {
   return Wire1.available() ? Wire1.read() : 0;
 }
 
-// ─── Temperature ──────────────────────────────────────────────────────────────
+// Temperature 
 float readIMUTemp() {
   int16_t raw = (int16_t)((imuReadReg(REG_OUT_TEMP_H) << 8) | imuReadReg(REG_OUT_TEMP_L));
   return 25.0f + (float)raw / 256.0f;
 }
 
-// ─── Calibration ──────────────────────────────────────────────────────────────
+// Calibration 
 void calibrateGyroBias() {
   Serial.println("[CAL] Hold still...");
   double sx=0, sy=0, sz=0;
@@ -33,7 +34,7 @@ void calibrateGyroBias() {
   biasGY = (float)(sy/BIAS_SAMPLES);
   biasGZ = (float)(sz/BIAS_SAMPLES);
   calTempC = readIMUTemp();
-  angleX = angleY = accumX = accumY = 0.0f;
+  accumX = accumY = 0.0f;
 
   #ifdef FEATURE_TELEMETRY
     statRecalCount++;
@@ -48,7 +49,7 @@ void calibrateGyroBias() {
   Serial.print(","); Serial.println(biasGZ,4);
 }
 
-// ─── Motion curve ─────────────────────────────────────────────────────────────
+// Motion curve 
 float applyCurve(float v) {
   switch (cfg.curve) {
     case CURVE_SQUARE: return (v >= 0 ? 1.f : -1.f) * v * v;

source/main.cpp

@@ -1,27 +1,12 @@
 /*
- * IMU BLE Mouse — Seeed XIAO nRF52840 Sense  (v3.4)
+ * IMU BLE Mouse - Seeed XIAO nRF52840 Sense  (v3.4)
  * ================================================================
- * Feature flags — comment out any line to disable that feature.
- * ATT table size is computed automatically from enabled features.
- * Start with minimal flags to isolate the SoftDevice RAM issue,
- * then re-enable one at a time.
- *
  * MINIMUM (just working mouse, no BLE config):
  *   leave only FEATURE_BATTERY_MONITOR + FEATURE_BOOT_LOOP_DETECT
  *
  * RECOMMENDED first test:
  *   enable FEATURE_CONFIG_SERVICE, keep TAP + STREAM + TELEMETRY off
  *
- * ── Feature flag index ───────────────────────────────────────────
- *   FEATURE_CONFIG_SERVICE    Custom GATT service (ConfigBlob + Command)
- *   FEATURE_TELEMETRY         +24-byte notify characteristic, 1 Hz
- *   FEATURE_IMU_STREAM        +14-byte notify characteristic, ~100 Hz
- *   FEATURE_TAP_DETECTION     LSM6DS3 hardware tap engine → L/R clicks
- *   FEATURE_TEMP_COMPENSATION Gyro drift correction by temperature delta
- *   FEATURE_AUTO_RECAL        Recalibrate after AUTO_RECAL_MS idle
- *   FEATURE_BATTERY_MONITOR   ADC battery read + BLE Battery Service
- *   FEATURE_BOOT_LOOP_DETECT  .noinit crash counter → safe mode
- *
  * Dependencies:
  *   FEATURE_TELEMETRY  requires FEATURE_CONFIG_SERVICE
  *   FEATURE_IMU_STREAM requires FEATURE_CONFIG_SERVICE
@@ -32,44 +17,46 @@
 #include "imu.h"
 #include "ble_config.h"
 #include "battery.h"
-#include "tap.h"
+#include "buttons.h"
 #include <bluefruit.h>
 #include <Adafruit_LittleFS.h>
 #include <InternalFileSystem.h>
 #include "Wire.h"
+#include "sleep.h"
 
-// ─── Boot-loop detection ──────────────────────────────────────────────────────
+// Boot-loop detection 
 #ifdef FEATURE_BOOT_LOOP_DETECT
   static uint32_t __attribute__((section(".noinit"))) bootCount;
   static uint32_t __attribute__((section(".noinit"))) bootMagic;
 #endif
 
-// ─── BLE Standard Services ────────────────────────────────────────────────────
+// BLE Standard Services 
 BLEDis         bledis;
 BLEHidAdafruit blehid;
 #ifdef FEATURE_BATTERY_MONITOR
   BLEBas blebas;
 #endif
 
-// ─── Persistence ──────────────────────────────────────────────────────────────
+// Persistence 
 using namespace Adafruit_LittleFS_Namespace;
 File cfgFile(InternalFS);
 
-// ─── Config definitions ───────────────────────────────────────────────────────
+// Config definitions 
 Config cfg;
 const Config CFG_DEFAULTS = {
   CONFIG_MAGIC, 600.0f, 0.060f, 0.08f, CURVE_LINEAR, 0x00, CHARGE_SLOW,
-  /*tapThreshold=*/12, /*tapAction=*/TAP_ACTION_LEFT, /*tapKey=*/0, /*tapMod=*/0
+  /*tapThreshold=*/12, /*tapAction=*/TAP_ACTION_KEY, /*tapKey=*/0x04, /*tapMod=*/0x03,  // Ctrl+Shift+A
+  /*jerkThreshold=*/2000.0f, /*tapFreezeEnabled=*/1, /*featureFlags=*/FLAG_ALL_DEFAULT
 };
 
-// ─── Telemetry definition ─────────────────────────────────────────────────────
+// Telemetry definition 
 #ifdef FEATURE_TELEMETRY
 TelemetryPacket telem = {};
 #endif
 
-// ─── Tuning constants ─────────────────────────────────────────────────────────
-const float ALPHA              = 0.96f;
+// Tuning constants
 const int   LOOP_RATE_MS       = 10;
+const float SMOOTH_ALPHA       = 0.65f;  // single-pole low-pass for cursor smoothing
 const int   BIAS_SAMPLES       = 200;
 const int   IDLE_FRAMES        = 150;
 const unsigned long BATT_REPORT_MS       = 20000;
@@ -78,7 +65,7 @@ const unsigned long HEARTBEAT_MS         = 10000;
 const int           HEARTBEAT_DUR        = 30;
 const unsigned long BOOT_SAFE_MS         = 5000;
 #ifdef FEATURE_IMU_STREAM
-  const unsigned long IMU_STREAM_RATE_MS = 50;
+  const unsigned long IMU_STREAM_RATE_MS = 20;
 #endif
 const float BATT_FULL                    = 4.20f;
 const float BATT_EMPTY                   = 3.00f;
@@ -93,8 +80,7 @@ const float BATT_CRITICAL                = 3.10f;
   const unsigned long AUTO_RECAL_MS = 5UL * 60UL * 1000UL;
 #endif
 
-// ─── Global state definitions ─────────────────────────────────────────────────
-float angleX = 0, angleY = 0;
+// Global state definitions
 float accumX = 0, accumY = 0;
 float biasGX = 0, biasGY = 0, biasGZ = 0;
 float calTempC    = 25.0f;
@@ -110,10 +96,25 @@ float cachedTempC = 25.0f;
 
 #ifdef FEATURE_IMU_STREAM
   bool imuStreamEnabled = false;
+  uint32_t streamNotifyFails = 0;
+  uint32_t streamNotifyOk   = 0;
+  unsigned long lastStreamDiag = 0;
+  // Back-off state: after STREAM_BACKOFF_THRESH consecutive fails, skip notifies
+  // for STREAM_BACKOFF_MS to let the SoftDevice HVN TX semaphore drain.
+  // Without this, every notify() blocks for BLE_GENERIC_TIMEOUT (100ms).
+  uint8_t       streamConsecFails = 0;
+  unsigned long streamBackoffUntil = 0;
+  const uint8_t        STREAM_BACKOFF_THRESH = 2;    // fails before backing off
+  const unsigned long  STREAM_BACKOFF_MS     = 500;  // cooldown window
 #endif
 
+uint32_t loopStalls = 0;          // loop iterations where dt > 20ms (behind schedule)
 bool pendingCal   = false;
 bool pendingReset = false;
+#ifdef FEATURE_OTA
+  bool pendingOTA = false;
+#endif
+
 
 ChargeStatus lastChargeStatus = CHGSTAT_DISCHARGING;
 
@@ -136,7 +137,7 @@ unsigned long bootStartMs   = 0;
 bool safeMode         = false;
 bool bootCountCleared = false;
 
-// ─── Advertising ─────────────────────────────────────────────────────────────
+// Advertising 
 static void startAdvertising() {
   Bluefruit.Advertising.addFlags(BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE);
   Bluefruit.Advertising.addTxPower();
@@ -152,7 +153,7 @@ static void startAdvertising() {
   Bluefruit.Advertising.start(0);
 }
 
-// ─── Setup ────────────────────────────────────────────────────────────────────
+// Setup 
 void setup() {
   Serial.begin(115200);
   unsigned long serialWait = millis();
@@ -163,14 +164,14 @@ void setup() {
   pinMode(LED_GREEN, OUTPUT); digitalWrite(LED_GREEN, HIGH);
   pinMode(LED_BLUE,  OUTPUT); digitalWrite(LED_BLUE,  HIGH);
 
-  // ── Boot-loop detection ───────────────────────────────────────────────────
+  // Boot-loop detection 
   #ifdef FEATURE_BOOT_LOOP_DETECT
     if (bootMagic != 0xCAFEBABE) { bootMagic = 0xCAFEBABE; bootCount = 0; }
     bootCount++;
     Serial.print("[BOOT] count="); Serial.println(bootCount);
     if (bootCount >= 3) {
       bootCount = 0; safeMode = true;
-      Serial.println("[BOOT] Boot loop — safe mode (no config service)");
+      Serial.println("[BOOT] Boot loop - safe mode (no config service)");
       InternalFS.begin(); InternalFS.remove(CONFIG_FILENAME);
       for (int i=0; i<3; i++) { digitalWrite(LED_RED,LOW); delay(150); digitalWrite(LED_RED,HIGH); delay(150); }  // fault: red
     }
@@ -189,7 +190,7 @@ void setup() {
   Bluefruit.begin(1, 0);
   Bluefruit.setTxPower(4);
   Bluefruit.setName(safeMode ? "IMU Mouse (safe)" : "IMU Mouse");
-  Bluefruit.Periph.setConnInterval(12, 24);  // 15-30ms — less aggressive, prevents stream disconnect
+  Bluefruit.Periph.setConnInterval(16, 32);  // 20-40ms - wider interval reduces SoftDevice TX stalls
 
   Wire1.begin();  // LSM6DS3 is on internal I2C bus (Wire1), must init before imu.begin()
   if (imu.begin() != 0) {
@@ -199,7 +200,11 @@ void setup() {
   Serial.println("[OK] IMU ready");
 
   #ifdef FEATURE_TAP_DETECTION
-    setupTapDetection();
+    if (cfg.featureFlags & FLAG_TAP_ENABLED) setupTapDetection();
+  #endif
+
+  #ifdef FEATURE_PHYSICAL_BUTTONS
+    setupPhysicalButtons();
   #endif
 
   cachedTempC = readIMUTemp();
@@ -211,6 +216,8 @@ void setup() {
 
   calibrateGyroBias();
 
+  sleepManagerInit();
+
   bledis.setManufacturer("Seeed Studio");
   bledis.setModel("XIAO nRF52840 Sense");
   bledis.begin();
@@ -218,7 +225,7 @@ void setup() {
   blehid.begin();
 
   #ifdef FEATURE_BATTERY_MONITOR
-    blebas.begin(); blebas.write(100);
+    blebas.begin(); blebas.write(batteryPercent(readBatteryVoltage()));
   #endif
 
   #ifdef FEATURE_CONFIG_SERVICE
@@ -231,7 +238,7 @@ void setup() {
   #endif
 
   startAdvertising();
-  Serial.print("[OK] Advertising — features:");
+  Serial.print("[OK] Advertising - features:");
   #ifdef FEATURE_CONFIG_SERVICE
     Serial.print(" CFG");
   #endif
@@ -256,13 +263,17 @@ void setup() {
   #ifdef FEATURE_BOOT_LOOP_DETECT
     Serial.print(" BOOTDET");
   #endif
+  #ifdef FEATURE_PHYSICAL_BUTTONS
+    Serial.print(" PHYSBTN");
+  #endif
+  Serial.print(" SLEEP");
   Serial.println();
 
   bootStartMs = millis();
   lastTime = lastBattTime = lastHeartbeat = lastTelemetry = millis();
 }
 
-// ─── Loop ─────────────────────────────────────────────────────────────────────
+// Loop 
 void loop() {
   unsigned long now = millis();
 
@@ -270,19 +281,39 @@ void loop() {
   #ifdef FEATURE_BOOT_LOOP_DETECT
     if (!bootCountCleared && (now - bootStartMs >= BOOT_SAFE_MS)) {
       bootCount = 0; bootCountCleared = true;
-      Serial.println("[BOOT] Stable — counter cleared");
+      Serial.println("[BOOT] Stable - counter cleared");
     }
   #endif
 
-  // Serial commands: 'c' = calibrate, 'r' = factory reset
+  // Serial commands: 'c' = calibrate, 'r' = factory reset, 'd' = axis diagnostic
+  static unsigned long diagUntil = 0;
   while (Serial.available()) {
     char cmd = Serial.read();
     if (cmd == 'c') { Serial.println("[SERIAL] Calibrate"); pendingCal   = true; }
     if (cmd == 'r') { Serial.println("[SERIAL] Reset");     pendingReset = true; }
+    if (cmd == 'd') { Serial.println("[DIAG] Printing raw gyro for 10s — pan, nod, roll one at a time"); diagUntil = now + 10000; }
+    #ifdef FEATURE_OTA
+      if (cmd == 'o') { Serial.println("[SERIAL] OTA DFU"); pendingOTA = true; }
+    #endif
   }
 
   if (pendingCal)   { pendingCal = false; calibrateGyroBias(); }
   if (pendingReset) { pendingReset = false; factoryReset(); }
+  #ifdef FEATURE_OTA
+    if (pendingOTA) {
+      pendingOTA = false;
+      Serial.println("[OTA] Disconnecting BLE and entering bootloader DFU mode...");
+      Serial.flush();
+      // Gracefully close the BLE connection first so the host can detect the
+      // disconnect and be ready to see DfuTarg advertise after the reboot.
+      if (Bluefruit.connected()) {
+        Bluefruit.disconnect(0);
+        delay(300);
+      }
+      delay(200);
+      enterOTADfu();  // Adafruit nRF52 core: sets GPREGRET correctly and resets into bootloader OTA mode
+    }
+  #endif
 
   // Heartbeat LED
   if (now - lastHeartbeat >= HEARTBEAT_MS) {
@@ -296,13 +327,25 @@ void loop() {
   #endif
 
   #ifdef FEATURE_TAP_DETECTION
-    processTaps(now);
+    if (cfg.featureFlags & FLAG_TAP_ENABLED) processTaps(now);
   #endif
 
+  #ifdef FEATURE_PHYSICAL_BUTTONS
+    processPhysicalButtons();
+  #endif
+  {
+    bool idle_for_sleep = (sleepStage == SLEEP_IMU_LP) ? true
+                          : (idleFrames >= IDLE_FRAMES);
+    if (sleepManagerUpdate(now, idle_for_sleep, Bluefruit.connected())) return;
+  }
+
   if (now - lastTime < (unsigned long)LOOP_RATE_MS) return;
   float dt = (now - lastTime) / 1000.0f;
   lastTime = now;
   if (dt <= 0.0f || dt > 0.5f) return;
+  // Threshold 50ms: intentional heartbeat blink (30ms) won't false-trigger;
+  // real SoftDevice stalls (100ms+) and unexpected delays still get flagged.
+  if (dt > 0.050f) { loopStalls++; Serial.print("[STALL] dt="); Serial.print(dt*1000.f,1); Serial.print("ms stalls="); Serial.println(loopStalls); }
 
   cachedTempC = readIMUTemp();
 
@@ -312,38 +355,51 @@ void loop() {
     }
   #endif
 
-  // Gyro reads with optional temperature compensation
-  float gx, gy, gz;
+  // Gyro reads with optional temperature compensation.
+  float correction = 0.0f;
   #ifdef FEATURE_TEMP_COMPENSATION
-    float correction = TEMP_COMP_COEFF_DPS_C * (cachedTempC - calTempC);
-    gx = (imu.readFloatGyroX() - biasGX - correction) * (PI/180.0f);
-    gy = (imu.readFloatGyroY() - biasGY - correction) * (PI/180.0f);
-    gz = (imu.readFloatGyroZ() - biasGZ - correction) * (PI/180.0f);
-  #else
-    gx = (imu.readFloatGyroX() - biasGX) * (PI/180.0f);
-    gy = (imu.readFloatGyroY() - biasGY) * (PI/180.0f);
-    gz = (imu.readFloatGyroZ() - biasGZ) * (PI/180.0f);
+    if (cfg.featureFlags & FLAG_TEMP_COMP_ENABLED)
+      correction = TEMP_COMP_COEFF_DPS_C * (cachedTempC - calTempC);
+  #endif
+  float gx = (imu.readFloatGyroX() - biasGX) * (PI/180.0f);             // roll (unused for cursor)
+  float gy = (imu.readFloatGyroY() - biasGY - correction) * (PI/180.0f); // pitch → cursor Y
+  float gz = (imu.readFloatGyroZ() - biasGZ - correction) * (PI/180.0f); // yaw   → cursor X
+
+  // Axis diagnostic — send 'd' over serial to enable
+  if (diagUntil && now < diagUntil) {
+    static unsigned long lastDiagPrint = 0;
+    if (now - lastDiagPrint >= 100) { lastDiagPrint = now;
+      Serial.print("[DIAG] gx="); Serial.print(gx,3);
+      Serial.print(" gy="); Serial.print(gy,3);
+      Serial.print(" gz="); Serial.println(gz,3);
+    }
+  } else if (diagUntil) { diagUntil = 0; Serial.println("[DIAG] Done"); }
+
+  // Direct axis mapping (empirically verified via diagnostic)
+  float yawRate   =  gz;  // gyroZ = pan left/right → cursor X
+  float pitchRate =  gy;  // gyroY = nod up/down    → cursor Y
+
+  // Dead zone (equal for both axes)
+  float fYaw   = (fabsf(yawRate)   > cfg.deadZone) ? yawRate   : 0.0f;
+  float fPitch = (fabsf(pitchRate) > cfg.deadZone) ? pitchRate : 0.0f;
+
+  #ifdef DEBUG
+  { static unsigned long lastDiag = 0;
+    if (now - lastDiag >= 500) { lastDiag = now;
+      Serial.print("[IMU] gyro="); Serial.print(gx,2); Serial.print(","); Serial.print(gy,2); Serial.print(","); Serial.print(gz,2);
+      Serial.print(" yaw="); Serial.print(yawRate,3); Serial.print(" pitch="); Serial.println(pitchRate,3);
+    }
+  }
   #endif
 
-  float ax = imu.readFloatAccelX();
-  float ay = imu.readFloatAccelY();
-  float az = imu.readFloatAccelZ();
-
-  // Complementary filter
-  angleX = ALPHA*(angleX + gx*dt) + (1.0f - ALPHA)*atan2f(ax, sqrtf(ay*ay + az*az));
-  angleY = ALPHA*(angleY + gy*dt) + (1.0f - ALPHA)*atan2f(ay, sqrtf(ax*ax + az*az));
-
-  float fGy = (fabsf(gy) > cfg.deadZone) ? gy : 0.0f;
-  float fGz = (fabsf(gz) > cfg.deadZone) ? gz : 0.0f;
-
-  bool moving = (fGy != 0.0f || fGz != 0.0f);
+  bool moving = (fPitch != 0.0f || fYaw != 0.0f);
   if  (moving) { idleFrames = 0; idleStartMs = 0; }
   else         { idleFrames++; if (idleStartMs == 0) idleStartMs = now; }
   bool idle = (idleFrames >= IDLE_FRAMES);
 
   #ifdef FEATURE_AUTO_RECAL
-    if (idle && idleStartMs != 0 && (now - idleStartMs >= AUTO_RECAL_MS)) {
-      Serial.println("[AUTO-CAL] Long idle — recalibrating...");
+    if ((cfg.featureFlags & FLAG_AUTO_RECAL_ENABLED) && idle && idleStartMs != 0 && (now - idleStartMs >= AUTO_RECAL_MS)) {
+      Serial.println("[AUTO-CAL] Long idle - recalibrating...");
       idleStartMs = 0; calibrateGyroBias(); return;
     }
   #endif
@@ -351,15 +407,21 @@ void loop() {
   int8_t  moveX = 0, moveY = 0;
   uint8_t flags = 0;
 
+  static float smoothX = 0.0f, smoothY = 0.0f;
+
   if (idle) {
+    smoothX = smoothY = 0.0f;
     accumX = accumY = 0.0f;
     flags |= 0x01;
   } else {
-    float rawX = applyAcceleration(applyCurve(-fGz * cfg.sensitivity * dt));
-    float rawY = applyAcceleration(applyCurve(-fGy * cfg.sensitivity * dt));
+    float rawX = applyAcceleration(applyCurve(-fYaw   * cfg.sensitivity * dt));
+    float rawY = applyAcceleration(applyCurve(-fPitch * cfg.sensitivity * dt));
     if (cfg.axisFlip & 0x01) rawX = -rawX;
     if (cfg.axisFlip & 0x02) rawY = -rawY;
-    accumX += rawX; accumY += rawY;
+    // Single-pole low-pass smoothing
+    smoothX = smoothX * (1.0f - SMOOTH_ALPHA) + rawX * SMOOTH_ALPHA;
+    smoothY = smoothY * (1.0f - SMOOTH_ALPHA) + rawY * SMOOTH_ALPHA;
+    accumX += smoothX; accumY += smoothY;
     moveX = (int8_t)constrain((int)accumX, -127, 127);
     moveY = (int8_t)constrain((int)accumY, -127, 127);
     accumX -= moveX; accumY -= moveY;
@@ -370,8 +432,13 @@ void loop() {
     if (!safeMode && imuStreamEnabled && Bluefruit.connected()
         && (now - lastImuStream >= IMU_STREAM_RATE_MS)) {
       lastImuStream = now;
+
+      if (now < streamBackoffUntil) {
+        // Backing off - host TX buffer congested, skip to avoid 100ms block
+      } else {
+        float ax = imu.readFloatAccelX(), ay = imu.readFloatAccelY(), az = imu.readFloatAccelZ();
         ImuPacket pkt;
-      pkt.gyroY_mDPS = (int16_t)constrain(gy*(180.f/PI)*1000.f, -32000, 32000);
+        pkt.gyroX_mDPS = (int16_t)constrain(gx*(180.f/PI)*1000.f, -32000, 32000);
         pkt.gyroZ_mDPS = (int16_t)constrain(gz*(180.f/PI)*1000.f, -32000, 32000);
         pkt.accelX_mg  = (int16_t)constrain(ax*1000.f, -32000, 32000);
         pkt.accelY_mg  = (int16_t)constrain(ay*1000.f, -32000, 32000);
@@ -380,15 +447,29 @@ void loop() {
         pkt.moveY      = moveY;
         pkt.flags      = flags;
         pkt._pad       = 0;
-      cfgImuStream.notify((uint8_t*)&pkt, sizeof(pkt));
+        if (cfgImuStream.notify((uint8_t*)&pkt, sizeof(pkt))) {
+          streamNotifyOk++;
+          streamConsecFails = 0;
+        } else {
+          streamNotifyFails++;
+          streamConsecFails++;
+          if (streamConsecFails >= STREAM_BACKOFF_THRESH) {
+            streamBackoffUntil = now + STREAM_BACKOFF_MS;
+            streamConsecFails  = 0;
+            Serial.print("[STREAM] TX congested - backing off ");
+            Serial.print(STREAM_BACKOFF_MS); Serial.println("ms");
+          }
+        }
+      }
+
+      // Periodic stream health report every 10 seconds
+      if (now - lastStreamDiag >= 10000) {
+        lastStreamDiag = now;
+        Serial.print("[STREAM] ok="); Serial.print(streamNotifyOk);
+        Serial.print(" fail="); Serial.print(streamNotifyFails);
+        Serial.print(" rate="); Serial.print((streamNotifyOk * 1000UL) / 10000); Serial.println("pkt/s");
+        streamNotifyOk = 0; streamNotifyFails = 0;
+      }
     }
   #endif
-
-  #ifdef DEBUG
-    Serial.print("T="); Serial.print(cachedTempC,1);
-    Serial.print(" gy="); Serial.print(gy,3);
-    Serial.print(" gz="); Serial.print(gz,3);
-    Serial.print(" mx="); Serial.print(moveX);
-    Serial.print(" my="); Serial.println(moveY);
-  #endif
 }

source/sleep.cpp

@@ -0,0 +1,364 @@
+#include "sleep.h"
+#include "imu.h"       // config.h REG_* macros
+#include <bluefruit.h> // sd_app_evt_wait()
+#include "Wire.h"
+
+// Registers not in config.h 
+#define SLP_CTRL2_G      0x11
+#define SLP_CTRL6_C      0x15
+#define SLP_CTRL7_G      0x16
+#define SLP_WAKE_UP_DUR  0x5C
+#define SLP_WAKE_UP_SRC  0x1B
+
+#define LSM_ADDR     0x6A
+
+#define XL_ODR_26HZ  0x20
+#define XL_ODR_416HZ 0x60
+#define G_ODR_416HZ  0x60
+
+// Module state 
+volatile SleepStage sleepStage  = SLEEP_AWAKE;
+volatile bool       imuWakeFlag = false;
+
+static unsigned long idleEnteredMs  = 0;  // when motion pipeline first went idle
+static unsigned long wakeSettleMs   = 0;  // when sleepManagerWakeIMU() was called
+static unsigned long lpEnteredMs    = 0;  // when IMU LP was entered (for recal decision)
+
+static bool          wasIdle        = false;
+static uint8_t       savedCtrl1XL   = XL_ODR_416HZ;
+static uint8_t       savedCtrl2G    = G_ODR_416HZ;
+static volatile bool pendingWakeSettle = false;  // always set on wake - 120ms blackout
+static volatile bool pendingWakeRecal  = false;  // set only when recal is also needed
+
+// Only force recalibration after waking from deep sleep, or after the gyro
+// has been off long enough for thermal drift to matter (~5 minutes).
+static constexpr unsigned long RECAL_AFTER_LP_MS = 5UL * 60UL * 1000UL;
+
+// Post-wake stillness gate: don't calibrate while the device is moving.
+// Each axis of the gyro must stay below RECAL_STILL_DPS for RECAL_STILL_FRAMES
+// consecutive loop ticks before calibration fires. If the device keeps moving
+// past RECAL_WAIT_MAX_MS, recal is skipped and the pre-sleep bias is kept.
+static constexpr float         RECAL_STILL_DPS    = 10.0f;  // deg/s per axis
+static constexpr uint8_t       RECAL_STILL_FRAMES = 10;     // ~100 ms at 10 ms/frame
+static constexpr unsigned long RECAL_WAIT_MAX_MS  = 3000;   // give up after 3 s
+
+static uint8_t       recalStillFrames = 0;
+static unsigned long recalLastWarnMs  = 0;
+
+// I2C helpers - Wire1 at 0x6A (SA0 LOW on XIAO nRF52840 Sense) 
+static uint8_t lsmRead(uint8_t reg) {
+  Wire1.beginTransmission(LSM_ADDR);
+  Wire1.write(reg);
+  Wire1.endTransmission(false);
+  Wire1.requestFrom(LSM_ADDR, (uint8_t)1);
+  return Wire1.available() ? Wire1.read() : 0xFF;
+}
+
+static void lsmWrite(uint8_t reg, uint8_t val) {
+  Wire1.beginTransmission(LSM_ADDR);
+  Wire1.write(reg);
+  Wire1.write(val);
+  Wire1.endTransmission();
+}
+
+// ISR
+static void imuInt1ISR() {
+  imuWakeFlag = true;
+}
+
+static volatile bool btnWakeFlag = false;
+static void btnWakeISR() {
+  btnWakeFlag = true;
+}
+
+// Arm wakeup interrupt 
+static void armWakeupInterrupt() {
+  lsmWrite(SLP_WAKE_UP_DUR, (uint8_t)((SLEEP_WAKEUP_DUR & 0x03) << 4));
+
+  // Preserve bit7 (tap single/double enable)
+  uint8_t wuth = lsmRead(REG_WAKE_UP_THS);
+  wuth = (wuth & 0xC0) | (SLEEP_WAKEUP_THS & 0x3F);
+  lsmWrite(REG_WAKE_UP_THS, wuth);
+
+  // INTERRUPTS_ENABLE=1, SLOPE_FDS=0 (HP filter is gated in LP - must be 0)
+  uint8_t tcfg = lsmRead(REG_TAP_CFG);
+  tcfg |=  (1 << 7);
+  tcfg &= ~(1 << 4);
+  lsmWrite(REG_TAP_CFG, tcfg);
+
+  uint8_t md1 = lsmRead(REG_MD1_CFG);
+  md1 |= (1 << 5);
+  lsmWrite(REG_MD1_CFG, md1);
+
+  // Clear any stale latch BEFORE re-arming the edge interrupt.
+  (void)lsmRead(SLP_WAKE_UP_SRC);
+  delay(2);
+
+  // Re-attach with RISING - guaranteed clean edge now that latch is cleared
+  detachInterrupt(digitalPinToInterrupt(IMU_INT1_PIN));
+  attachInterrupt(digitalPinToInterrupt(IMU_INT1_PIN), imuInt1ISR, RISING);
+  imuWakeFlag = false;
+
+#ifdef DEBUG
+  Serial.print("[SLEEP] armWakeup - TAP_CFG=0x"); Serial.print(lsmRead(REG_TAP_CFG), HEX);
+  Serial.print(" MD1_CFG=0x"); Serial.print(lsmRead(REG_MD1_CFG), HEX);
+  Serial.print(" WAKE_UP_THS=0x"); Serial.println(lsmRead(REG_WAKE_UP_THS), HEX);
+#endif
+}
+
+static void disarmWakeupInterrupt() {
+  // Restore SLOPE_FDS=1 for tap detection HP filter path
+  uint8_t tcfg = lsmRead(REG_TAP_CFG);
+  tcfg |= (1 << 4);
+  lsmWrite(REG_TAP_CFG, tcfg);
+
+  // Clear INT1_WU to stop wakeup engine driving INT1 at full rate
+  uint8_t md1 = lsmRead(REG_MD1_CFG);
+  md1 &= ~(1 << 5);
+  lsmWrite(REG_MD1_CFG, md1);
+}
+
+// Enter IMU LP 
+static void enterImuLP() {
+  if (sleepStage >= SLEEP_IMU_LP) return;
+
+  savedCtrl1XL = lsmRead(REG_CTRL1_XL);
+  savedCtrl2G  = lsmRead(SLP_CTRL2_G);
+
+  lsmWrite(SLP_CTRL2_G,  savedCtrl2G & 0x0F);                      // gyro off
+  lsmWrite(REG_CTRL1_XL, (savedCtrl1XL & 0x0F) | XL_ODR_26HZ);    // accel 26 Hz
+  lsmWrite(SLP_CTRL6_C,  lsmRead(SLP_CTRL6_C) | (1 << 4));         // XL_HM_MODE=1
+  lsmWrite(SLP_CTRL7_G,  lsmRead(SLP_CTRL7_G) | (1 << 7));         // G_HM_MODE=1
+
+  armWakeupInterrupt();
+
+  // Arm button wake interrupt
+  #if BTN_LEFT_PIN != BTN_PIN_NONE
+    btnWakeFlag = false;
+    attachInterrupt(digitalPinToInterrupt(BTN_LEFT_PIN), btnWakeISR, FALLING);
+  #endif
+
+  // Turn off all LEDs for sleep
+  digitalWrite(LED_RED, HIGH); digitalWrite(LED_GREEN, HIGH); digitalWrite(LED_BLUE, HIGH);
+
+  lpEnteredMs = millis();
+  sleepStage = SLEEP_IMU_LP;
+  Serial.print("[SLEEP] IMU LP entered - idle for ");
+  Serial.print((millis() - idleEnteredMs) / 1000); Serial.println("s");
+
+#ifdef DEBUG
+  Serial.print("[SLEEP] CTRL1_XL=0x"); Serial.print(lsmRead(REG_CTRL1_XL), HEX);
+  Serial.print(" CTRL2_G=0x");  Serial.print(lsmRead(SLP_CTRL2_G), HEX);
+  Serial.print(" CTRL6_C=0x");  Serial.print(lsmRead(SLP_CTRL6_C), HEX);
+  Serial.print(" CTRL7_G=0x");  Serial.println(lsmRead(SLP_CTRL7_G), HEX);
+  Serial.print("[SLEEP] TAP_CFG=0x");    Serial.print(lsmRead(REG_TAP_CFG), HEX);
+  Serial.print(" MD1_CFG=0x");          Serial.print(lsmRead(REG_MD1_CFG), HEX);
+  Serial.print(" WAKE_UP_THS=0x");      Serial.print(lsmRead(REG_WAKE_UP_THS), HEX);
+  Serial.print(" WAKE_UP_DUR=0x");      Serial.println(lsmRead(SLP_WAKE_UP_DUR), HEX);
+#endif
+}
+
+// Enter deep sleep 
+static void enterDeepSleep() {
+  if (sleepStage >= SLEEP_DEEP) return;
+  if (sleepStage < SLEEP_IMU_LP) enterImuLP();
+
+  sleepStage = SLEEP_DEEP;
+  Serial.println("[SLEEP] Deep sleep - WFE on INT1");
+  Serial.flush();
+
+  digitalWrite(LED_RED, HIGH); digitalWrite(LED_GREEN, HIGH); digitalWrite(LED_BLUE, HIGH);
+
+  while (!imuWakeFlag && !btnWakeFlag) {
+    (void)lsmRead(SLP_WAKE_UP_SRC);
+    sd_app_evt_wait();
+  }
+}
+
+// Public: wake 
+void sleepManagerWakeIMU() {
+  (void)lsmRead(SLP_WAKE_UP_SRC);
+
+  lsmWrite(SLP_CTRL6_C, lsmRead(SLP_CTRL6_C) & ~(1 << 4));
+  lsmWrite(SLP_CTRL7_G, lsmRead(SLP_CTRL7_G) & ~(1 << 7));
+  lsmWrite(REG_CTRL1_XL, savedCtrl1XL);
+  lsmWrite(SLP_CTRL2_G,  savedCtrl2G);
+
+  disarmWakeupInterrupt();
+
+  // Detach button wake interrupt — normal polling takes over
+  #if BTN_LEFT_PIN != BTN_PIN_NONE
+    detachInterrupt(digitalPinToInterrupt(BTN_LEFT_PIN));
+  #endif
+
+  // Only recalibrate if gyro was off long enough for thermal drift to accumulate,
+  // or if waking from full deep sleep. Short LP naps reuse the existing bias.
+  unsigned long lpDuration = millis() - lpEnteredMs;
+  bool needsRecal = (sleepStage == SLEEP_DEEP) || (lpDuration >= RECAL_AFTER_LP_MS);
+
+  wakeSettleMs      = millis();
+  pendingWakeSettle = true;          // always block output for 120ms
+  pendingWakeRecal  = needsRecal;    // additionally recalibrate if needed
+
+  wasIdle       = false;
+  idleEnteredMs = 0;
+  lpEnteredMs   = 0;
+
+  // Reset motion filter state to prevent a cursor jump on the first frame.
+  extern float accumX, accumY;
+  extern unsigned long lastTime;
+  accumX = accumY = 0.0f;
+  lastTime = millis();
+
+  sleepStage = SLEEP_AWAKE;
+  if (needsRecal)
+    Serial.println("[SLEEP] Awake - gyro settling, recal needed");
+  else
+    Serial.println("[SLEEP] Awake - short LP, reusing existing bias");
+}
+
+// Public: init 
+void sleepManagerInit() {
+  pinMode(IMU_INT1_PIN, INPUT);
+  attachInterrupt(digitalPinToInterrupt(IMU_INT1_PIN), imuInt1ISR, RISING);
+
+  // Sanity check: WHO_AM_I should return 0x6A for LSM6DS3
+  uint8_t whoami = imuReadReg(0x0F);
+  Serial.print("[SLEEP] WHO_AM_I=0x"); Serial.print(whoami, HEX);
+  if (whoami == 0x6A) Serial.println(" (OK)");
+  else                Serial.println(" (WRONG - I2C not working, sleep disabled)");
+
+  if (whoami != 0x6A) return;  // don't arm anything if we can't talk to the IMU
+
+  Serial.print("[SLEEP] Init - INT1 pin="); Serial.print(IMU_INT1_PIN);
+  Serial.print(", WU_THS="); Serial.print(SLEEP_WAKEUP_THS);
+  Serial.print(" (~"); Serial.print(SLEEP_WAKEUP_THS * 7.8f, 0); Serial.print(" mg)");
+  Serial.print(", IMU_LP after "); Serial.print(SLEEP_IMU_IDLE_MS / 1000); Serial.print("s");
+  Serial.print(", deep after ");   Serial.print(SLEEP_DEEP_IDLE_MS / 1000); Serial.println("s");
+}
+
+// Public: per-loop update 
+// Must be called AFTER idleFrames/idle is updated by the motion pipeline.
+// Returns true → caller must skip IMU reads this iteration.
+bool sleepManagerUpdate(unsigned long nowMs, bool idle, bool bleConnected) {
+
+  // ISR wakeup (IMU motion or button press)
+  bool woke = false;
+  if (imuWakeFlag) {
+    imuWakeFlag = false;
+    Serial.print("[SLEEP] INT1 fired - stage="); Serial.println((int)sleepStage);
+    woke = true;
+  }
+  if (btnWakeFlag) {
+    btnWakeFlag = false;
+    Serial.print("[SLEEP] Button fired - stage="); Serial.println((int)sleepStage);
+    woke = true;
+  }
+  if (woke) {
+    if (sleepStage == SLEEP_DEEP || sleepStage == SLEEP_IMU_LP) {
+      sleepManagerWakeIMU();
+    } else {
+      (void)lsmRead(SLP_WAKE_UP_SRC);
+    }
+  }
+
+  // Post-wake recalibration — gated on device being still
+  if (pendingWakeRecal) {
+    if (nowMs - wakeSettleMs < 120) return true;  // initial hardware settle
+
+    // Sample gyro magnitude; each axis must be below threshold
+    float gx = fabsf(imu.readFloatGyroX());
+    float gy = fabsf(imu.readFloatGyroY());
+    float gz = fabsf(imu.readFloatGyroZ());
+    bool still = (gx < RECAL_STILL_DPS && gy < RECAL_STILL_DPS && gz < RECAL_STILL_DPS);
+
+    if (!still) {
+      recalStillFrames = 0;
+      // Rate-limited log so we don't flood serial while waiting
+      if (nowMs - recalLastWarnMs >= 500) {
+        recalLastWarnMs = nowMs;
+        Serial.print("[SLEEP] Waiting for still: gx="); Serial.print(gx, 1);
+        Serial.print(" gy="); Serial.print(gy, 1);
+        Serial.print(" gz="); Serial.println(gz, 1);
+      }
+      if (nowMs - wakeSettleMs >= RECAL_WAIT_MAX_MS) {
+        // Device never settled — keep pre-sleep bias rather than corrupt it
+        pendingWakeRecal = false;
+        recalStillFrames = 0;
+        recalLastWarnMs  = 0;
+        Serial.println("[SLEEP] Recal skipped — device still moving after timeout");
+      }
+      return true;
+    }
+
+    // Device is still — accumulate consecutive still frames
+    if (++recalStillFrames < RECAL_STILL_FRAMES) return true;
+
+    pendingWakeRecal = false;
+    recalStillFrames = 0;
+    recalLastWarnMs  = 0;
+    calibrateGyroBias();
+    Serial.println("[SLEEP] Post-wake recal done");
+    return true;
+  }
+
+  // IMU_LP path 
+  // main.cpp returns early when we return true, so idleFrames never increments
+  // and the motion pipeline's `idle` flag is stale. Use our own idleEnteredMs
+  // (captured before LP entry) to drive the deep-sleep countdown independently.
+  if (sleepStage == SLEEP_IMU_LP) {
+    // Periodic log: confirms loop is running, shows live INT1 pin level and
+    // WAKE_UP_SRC register. If INT1_pin never goes high after movement, the
+    // wakeup engine is not generating an interrupt - check register values.
+    static unsigned long lastLpLog = 0;
+    if (nowMs - lastLpLog >= 5000) {
+      lastLpLog = nowMs;
+      unsigned long lpSecs = idleEnteredMs ? (nowMs - idleEnteredMs) / 1000 : 0;
+      Serial.print("[SLEEP] LP tick - idle="); Serial.print(lpSecs);
+      Serial.print("s INT1="); Serial.print(digitalRead(IMU_INT1_PIN));
+      Serial.print(" WAKE_UP_SRC=0x"); Serial.println(lsmRead(SLP_WAKE_UP_SRC), HEX);
+    }
+    if (!bleConnected && idleEnteredMs != 0
+        && (nowMs - idleEnteredMs >= SLEEP_DEEP_IDLE_MS))
+    {
+      Serial.println("[SLEEP] Deep sleep threshold reached");
+      enterDeepSleep();
+    }
+    return true;
+  }
+
+  // AWAKE path 
+  if (!idle) {
+    if (wasIdle) {
+      Serial.println("[SLEEP] Motion - idle timer reset");
+    }
+    wasIdle       = false;
+    idleEnteredMs = 0;
+    return false;
+  }
+
+  if (!wasIdle) {
+    wasIdle       = true;
+    idleEnteredMs = nowMs;
+    Serial.println("[SLEEP] Idle started");
+  }
+
+  unsigned long idleElapsed = nowMs - idleEnteredMs;
+
+  // Progress report every 5 s while waiting for LP threshold
+  #ifdef DEBUG
+  { static unsigned long lastReport = 0;
+    if (nowMs - lastReport >= 5000) { lastReport = nowMs;
+      Serial.print("[SLEEP] idle="); Serial.print(idleElapsed/1000);
+      Serial.print("s / LP@"); Serial.print(SLEEP_IMU_IDLE_MS/1000); Serial.println("s");
+    }
+  }
+  #endif
+
+  if (idleElapsed >= SLEEP_IMU_IDLE_MS) {
+    enterImuLP();
+    return true;
+  }
+
+  return false;
+}

source/sleep.h

@@ -0,0 +1,39 @@
+#pragma once
+#include <Arduino.h>
+
+// Tuning 
+#ifndef SLEEP_IMU_IDLE_MS
+  #define SLEEP_IMU_IDLE_MS   (10UL * 1000UL)   // 10 s  → gyro off, accel LP
+#endif
+#ifndef SLEEP_DEEP_IDLE_MS
+  #define SLEEP_DEEP_IDLE_MS  (60UL * 1000UL)   // 60 s  → system deep sleep (no-BLE only)
+#endif
+
+// LSM6DS3 wakeup threshold: 1 LSB = 7.8 mg at ±2 g FS (±2g range).
+#ifndef SLEEP_WAKEUP_THS
+  #define SLEEP_WAKEUP_THS   6    // 0–63
+#endif
+
+// Number of consecutive 26 Hz samples that must exceed the threshold.
+#ifndef SLEEP_WAKEUP_DUR
+  #define SLEEP_WAKEUP_DUR   1    // 0–3
+#endif
+
+// GPIO pin connected to LSM6DS3 INT1.
+#ifndef IMU_INT1_PIN
+  #define IMU_INT1_PIN  PIN_LSM6DS3TR_C_INT1
+#endif
+
+// Public state (read-only from main.cpp) 
+enum SleepStage : uint8_t {
+  SLEEP_AWAKE  = 0,   // normal full-rate operation
+  SLEEP_IMU_LP = 1,   // gyro off, accel LP - nRF awake
+  SLEEP_DEEP   = 2,   // system WFE - BLE disconnected only
+};
+
+extern volatile SleepStage sleepStage;
+extern volatile bool       imuWakeFlag;
+
+void sleepManagerInit();
+bool sleepManagerUpdate(unsigned long nowMs, bool idle, bool bleConnected);
+void sleepManagerWakeIMU();

source/tap.cpp

@@ -6,7 +6,7 @@
 
 extern BLEHidAdafruit blehid;
 
-// ─── Tap detection setup ──────────────────────────────────────────────────────
+// Tap detection setup 
 // REG_TAP_THS_6D bits[4:0] = tapThreshold (1–31); 1 LSB = FS/32 = 62.5 mg at ±2g.
 // REG_INT_DUR2 at ODR=416 Hz:
 //  SHOCK[7:6] = 2 → 38 ms max tap duration
@@ -30,18 +30,7 @@ void setupTapDetection() {
   Serial.print(" (~"); Serial.print(cfg.tapThreshold * 62.5f, 0); Serial.println(" mg)");
 }
 
-// ─── Tap processing ───────────────────────────────────────────────────────────
-// Only double-tap is mapped to an action. Single-tap is ignored (it always fires
-// before the double is confirmed and cannot be reliably disambiguated on this
-// hardware without an unacceptable latency penalty).
-//
-// The LSM6DS3 sets SINGLE_TAP immediately on first contact — we wait until
-// DOUBLE_TAP is set (within the hardware DUR window of 115 ms) before acting.
-// An additional TAP_CONFIRM_MS guard ensures the TAP_SRC register has settled.
-//
-// IMPORTANT: call mouseButtonPress(bitmask) — single arg only. The two-arg
-// overload takes (conn_hdl, buttons) and sends the wrong button value.
-
+// Tap processing 
 static enum { TAP_IDLE, TAP_PENDING, TAP_EXECUTING } tapState = TAP_IDLE;
 static unsigned long tapPendingMs  = 0;
 static uint8_t       pendingButton = 0;   // 0 = key action pending
@@ -83,7 +72,7 @@ static void fireTapAction(unsigned long now) {
 }
 
 void processTaps(unsigned long now) {
-  // ── Release ───────────────────────────────────────────────────────────────
+  // Release 
   if (tapState == TAP_EXECUTING) {
     if (now - clickDownMs >= CLICK_HOLD_MS) {
       if (pendingButton) {
@@ -99,7 +88,7 @@ void processTaps(unsigned long now) {
     return;
   }
 
-  // ── Poll TAP_SRC ──────────────────────────────────────────────────────────
+  // Poll TAP_SRC 
   uint8_t tapSrc = imuReadReg(REG_TAP_SRC);
   bool tapIA     = !!(tapSrc & 0x40);
   bool doubleTap = !!(tapSrc & 0x10);

web/app.js

@@ -1,34 +1,73 @@
-// ── UUIDs ────────────────────────────────────────────────────────────────────
+// UUIDs 
 // v3.3: 4 characteristics instead of 10
 const SVC_UUID = '00001234-0000-1000-8000-00805f9b34fb';
 const CHR = {
-  configBlob:  '00001235-0000-1000-8000-00805f9b34fb',  // ConfigBlob R/W 16 bytes
+  configBlob:  '00001235-0000-1000-8000-00805f9b34fb',  // ConfigBlob R/W 20 bytes
   command:     '00001236-0000-1000-8000-00805f9b34fb',  // Command    W   1 byte
   telemetry:   '00001237-0000-1000-8000-00805f9b34fb',  // Telemetry  R/N 24 bytes
   imuStream:   '00001238-0000-1000-8000-00805f9b34fb',  // ImuStream  N   14 bytes
+  gitHash:     '00001239-0000-1000-8000-00805f9b34fb',  // GitHash    R   8 bytes
 };
 
+// Runtime feature-override flag bitmask constants (mirror firmware FLAG_* defines)
+const FLAG_TAP_ENABLED        = 0x01;
+const FLAG_TEMP_COMP_ENABLED  = 0x02;
+const FLAG_AUTO_RECAL_ENABLED = 0x04;
+const FLAG_ALL_DEFAULT        = FLAG_TAP_ENABLED | FLAG_TEMP_COMP_ENABLED | FLAG_AUTO_RECAL_ENABLED;
+
 // Local shadow of the current config (kept in sync with device)
-const config = { sensitivity:600, deadZone:0.06, accelStrength:0.08, curve:0, axisFlip:0, chargeMode:1,
-                 tapThreshold:12, tapAction:0, tapKey:0, tapMod:0 };
+const config = { sensitivity:600, deadZone:0.06, accelStrength:0.08, curve:0, axisFlip:0, chargeMode:0,
+                 tapThreshold:12, tapAction:0, tapKey:0, tapMod:0, tapFreezeEnabled:1, jerkThreshold:2000,
+                 featureFlags:FLAG_ALL_DEFAULT,
+                };
 
 let device=null, server=null, chars={}, userDisconnected=false;
-let currentChargeStatus=0, currentBattPct=null;
+let currentChargeStatus=0, currentBattPct=null, currentBattVoltage=null;
+let advancedMode = localStorage.getItem('advanced') === 'true';
 
-// ── GATT write queue (prevents "operation already in progress") ───────────────
+// GATT write queue (prevents "operation already in progress") 
+// Serialises all GATT writes. Features:
+//  • Per-operation 3s timeout - hangs don't block the queue forever
+//  • Max depth of 2 pending ops - drops excess writes when device goes silent
+//  • gattQueueReset() flushes on disconnect so a reconnect starts clean
+const GATT_TIMEOUT_MS = 3000;
+const GATT_MAX_DEPTH  = 2;
 let _gattQueue = Promise.resolve();
-function gattWrite(char, value) {
-  const p = _gattQueue.then(() => char.writeValueWithResponse(value));
-  _gattQueue = p.catch(() => {});
-  return p;
+let _gattDepth = 0;
+
+function _withTimeout(promise, ms) {
+  return new Promise((resolve, reject) => {
+    const t = setTimeout(() => {
+      console.warn(`[GATT] operation timed out after ${ms}ms`);
+      reject(new Error(`GATT timeout (${ms}ms)`));
+    }, ms);
+    promise.then(v => { clearTimeout(t); resolve(v); },
+                 e => { clearTimeout(t); reject(e); });
+  });
 }
-function gattCmd(char, value) {
-  const p = _gattQueue.then(() => char.writeValueWithoutResponse(value));
-  _gattQueue = p.catch(() => {});
+
+function _enqueue(fn) {
+  if (_gattDepth >= GATT_MAX_DEPTH) {
+    console.warn(`[GATT] write dropped - queue depth ${_gattDepth} >= max ${GATT_MAX_DEPTH}`);
+    return Promise.reject(new Error('GATT queue full - device unreachable?'));
+  }
+  _gattDepth++;
+  const p = _gattQueue.then(() => _withTimeout(fn(), GATT_TIMEOUT_MS));
+  _gattQueue = p.catch(() => {}).finally(() => { _gattDepth = Math.max(0, _gattDepth - 1); });
   return p;
 }
 
-// ── Logging ──────────────────────────────────────────────────────────────────
+function gattWrite(char, value) { return _enqueue(() => char.writeValueWithResponse(value)); }
+function gattCmd (char, value)  { return _enqueue(() => char.writeValueWithoutResponse(value)); }
+
+function gattQueueReset() {
+  console.log('[GATT] queue reset');
+  // Drain the chain so a reconnect starts with a fresh resolved promise
+  _gattQueue = Promise.resolve();
+  _gattDepth = 0;
+}
+
+// Logging 
 (function() {
   const _methods = { log: '', warn: 'warn', error: 'err' };
   for (const [method, type] of Object.entries(_methods)) {
@@ -51,7 +90,7 @@ function log(msg, type='') {
 const p2=n=>String(n).padStart(2,'0'), p3=n=>String(n).padStart(3,'0');
 function cssVar(n) { return getComputedStyle(document.documentElement).getPropertyValue(n).trim(); }
 
-// ── Connection ───────────────────────────────────────────────────────────────
+// Connection 
 async function doConnect() {
   if (!navigator.bluetooth) { log('Web Bluetooth not supported.','err'); return; }
   userDisconnected = false;
@@ -89,27 +128,34 @@ async function discoverServices() {
     chars.command    = await svc.getCharacteristic(CHR.command);
     chars.telemetry  = await svc.getCharacteristic(CHR.telemetry);
     chars.imuStream  = await svc.getCharacteristic(CHR.imuStream);
+    chars.gitHash    = await svc.getCharacteristic(CHR.gitHash);
 
     // Read config blob and populate UI
     await readConfigBlob();
 
-    // Telemetry notify (1 Hz) — also carries chargeStatus
-    chars.telemetry.addEventListener('characteristicvaluechanged', e => parseTelemetry(e.target.value));
-    await chars.telemetry.startNotifications();
-    // Initial read so values show immediately
-    parseTelemetry(await chars.telemetry.readValue());
+    // Read firmware git hash and check against web build hash
+    await checkHashMatch();
 
-    // IMU stream — subscribed on demand via play button
+    // Telemetry notify (1 Hz) - also carries chargeStatus
+    chars.telemetry.addEventListener('characteristicvaluechanged', e => {
+      const val = e.target.value;  // capture immediately — Chrome reuses the DataView buffer on next notify
+      parseTelemetry(val);
+    });
+    await chars.telemetry.startNotifications();
+    parseTelemetry(await chars.telemetry.readValue());
+    updateChargeUI();
+
+    // IMU stream - subscribed on demand via play button
     chars.imuStream.addEventListener('characteristicvaluechanged', e => parseImuStream(e.target.value));
 
     log('Config service ready (4 chars)','ok');
   } catch(e) {
     log(`Service discovery failed: ${e.message}`,'err');
     // Safe mode device might not have config service
-    if (e.message.includes('not found')) log('Device may be in safe mode — basic mouse only','warn');
+    if (e.message.includes('not found')) log('Device may be in safe mode - basic mouse only','warn');
   }
 
-  // Battery service (standard — always present)
+  // Battery service (standard - always present)
   try {
     const bsvc = await server.getPrimaryService('battery_service');
     const bch  = await bsvc.getCharacteristic('battery_level');
@@ -125,11 +171,52 @@ async function discoverServices() {
   } catch(e) { log('Battery service unavailable','warn'); }
 }
 
-// ── ConfigBlob read / write ──────────────────────────────────────────────────
-// ConfigBlob layout (20 bytes LE):
+// Firmware / web hash mismatch banner 
+async function checkHashMatch() {
+  const banner = document.getElementById('hashMismatchBanner');
+  if (!chars.gitHash) return;
+  let fwHash = 'unknown';
+  try {
+    const dv = await chars.gitHash.readValue();
+    const bytes = new Uint8Array(dv.buffer, dv.byteOffset, dv.byteLength);
+    // Find NUL terminator or use full length
+    let end = bytes.indexOf(0);
+    if (end === -1) end = bytes.length;
+    fwHash = new TextDecoder().decode(bytes.subarray(0, end));
+  } catch(e) { log(`Hash read failed: ${e.message}`, 'warn'); }
+
+  // FIRMWARE_BUILD_HASH comes from web/version.js (written by scripts/git_hash.py at build time)
+  const webHash = (typeof FIRMWARE_BUILD_HASH !== 'undefined') ? FIRMWARE_BUILD_HASH : 'unknown';
+
+  log(`Firmware hash: ${fwHash}  ·  Web hash: ${webHash}`, fwHash === webHash ? 'ok' : 'warn');
+
+  if (fwHash === 'unknown' || webHash === 'unknown' || fwHash === webHash) {
+    banner.style.display = 'none';
+    return;
+  }
+
+  banner.style.cssText = [
+    'display:flex', 'align-items:center', 'justify-content:center', 'gap:12px',
+    'background:#7a2020', 'color:#ffd0d0', 'font-family:var(--mono)',
+    'font-size:11px', 'padding:6px 16px', 'border-bottom:1px solid #c04040',
+    'position:sticky', 'top:0', 'z-index:100',
+  ].join(';');
+  banner.innerHTML =
+    `<span style="font-size:14px">⚠</span>` +
+    `<span>FIRMWARE / WEB MISMATCH - ` +
+    `firmware <b>${fwHash}</b> · web <b>${webHash}</b> - ` +
+    `flash firmware or reload the page after a <code>pio run</code></span>` +
+    `<button onclick="document.getElementById('hashMismatchBanner').style.display='none'" ` +
+    `style="margin-left:8px;background:none;border:1px solid #c04040;color:#ffd0d0;` +
+    `cursor:pointer;padding:2px 8px;font-family:var(--mono);font-size:10px">✕</button>`;
+}
+
+// ConfigBlob read / write 
+// ConfigBlob layout (25 bytes LE):
 //  float sensitivity [0], float deadZone [4], float accelStrength [8]
-//   uint8 curve [12], uint8 axisFlip [13], uint8 chargeMode [14]
-//   uint8 tapThreshold [15], uint8 tapAction [16], uint8 tapKey [17], uint8 tapMod [18], uint8 pad [19]
+//  uint8 curve [12], uint8 axisFlip [13], uint8 chargeMode [14] (0=SLOW 1=FAST)
+//  uint8 tapThreshold [15], uint8 tapAction [16], uint8 tapKey [17], uint8 tapMod [18], uint8 tapFreezeEnabled [19]
+//  float jerkThreshold [20], uint8 featureFlags [24]
 
 async function readConfigBlob() {
   if (!chars.configBlob) return;
@@ -147,9 +234,18 @@ async function readConfigBlob() {
       config.tapAction       = view.getUint8(16);
       config.tapKey          = view.getUint8(17);
       config.tapMod          = view.getUint8(18);
+      config.tapFreezeEnabled = view.getUint8(19);
+    }
+    if (view.byteLength >= 24) {
+      config.jerkThreshold = view.getFloat32(20, true);
+    }
+    if (view.byteLength >= 25) {
+      config.featureFlags = view.getUint8(24);
+    } else {
+      config.featureFlags = FLAG_ALL_DEFAULT;  // old firmware - assume all on
     }
     applyConfigToUI();
-    log(`Config loaded — sens=${config.sensitivity.toFixed(0)} dz=${config.deadZone.toFixed(3)} tapThr=${config.tapThreshold}`,'ok');
+    log(`Config loaded - sens=${config.sensitivity.toFixed(0)} dz=${config.deadZone.toFixed(3)} tapThr=${config.tapThreshold}`,'ok');
   } catch(e) { log(`Config read error: ${e.message}`,'err'); }
 }
 
@@ -164,6 +260,10 @@ function applyConfigToUI() {
   document.getElementById('flipX').checked = !!(config.axisFlip & 1);
   document.getElementById('flipY').checked = !!(config.axisFlip & 2);
   setChargeModeUI(config.chargeMode);
+  document.getElementById('tapFreezeEnabled').checked = !!config.tapFreezeEnabled;
+  document.getElementById('slJerkThreshold').value = config.jerkThreshold;
+  updateDisplay('jerkThreshold', config.jerkThreshold);
+  updateTapFreezeUI(!!config.tapFreezeEnabled);
   document.getElementById('slTapThreshold').value = config.tapThreshold;
   updateDisplay('tapThreshold', config.tapThreshold);
   setTapActionUI(config.tapAction);
@@ -172,8 +272,12 @@ function applyConfigToUI() {
   document.getElementById('tapModShift').checked = !!(config.tapMod & 0x02);
   document.getElementById('tapModAlt').checked   = !!(config.tapMod & 0x04);
   document.getElementById('tapModGui').checked   = !!(config.tapMod & 0x08);
+  document.getElementById('capTapEnabled').checked  = !!(config.featureFlags & FLAG_TAP_ENABLED);
+  document.getElementById('capTempComp').checked    = !!(config.featureFlags & FLAG_TEMP_COMP_ENABLED);
+  document.getElementById('capAutoRecal').checked   = !!(config.featureFlags & FLAG_AUTO_RECAL_ENABLED);
 }
 
+
 let _writeConfigTimer = null;
 function writeConfigBlob() {
   clearTimeout(_writeConfigTimer);
@@ -193,9 +297,14 @@ async function _doWriteConfigBlob() {
                        | (document.getElementById('tapModShift').checked ? 0x02 : 0)
                        | (document.getElementById('tapModAlt').checked   ? 0x04 : 0)
                        | (document.getElementById('tapModGui').checked   ? 0x08 : 0);
+  config.tapFreezeEnabled = document.getElementById('tapFreezeEnabled').checked ? 1 : 0;
+  config.jerkThreshold = +document.getElementById('slJerkThreshold').value;
+  config.featureFlags  = (document.getElementById('capTapEnabled').checked  ? FLAG_TAP_ENABLED        : 0)
+                       | (document.getElementById('capTempComp').checked    ? FLAG_TEMP_COMP_ENABLED  : 0)
+                       | (document.getElementById('capAutoRecal').checked   ? FLAG_AUTO_RECAL_ENABLED : 0);
   // config.curve, config.chargeMode, config.tapAction, config.tapKey updated directly
 
-  const buf  = new ArrayBuffer(20);
+  const buf  = new ArrayBuffer(25);
   const view = new DataView(buf);
   view.setFloat32(0,  config.sensitivity,   true);
   view.setFloat32(4,  config.deadZone,      true);
@@ -207,15 +316,17 @@ async function _doWriteConfigBlob() {
   view.setUint8(16, config.tapAction);
   view.setUint8(17, config.tapKey);
   view.setUint8(18, config.tapMod);
-  view.setUint8(19, 0);
+  view.setUint8(19, config.tapFreezeEnabled);
+  view.setFloat32(20, config.jerkThreshold, true);
+  view.setUint8(24, config.featureFlags);
 
   try {
     await gattWrite(chars.configBlob, buf);
-    log(`Config written — sens=${config.sensitivity.toFixed(0)} tapThr=${config.tapThreshold} tapAction=${config.tapAction}`,'ok');
+    log(`Config written - sens=${config.sensitivity.toFixed(0)} tapThr=${config.tapThreshold} tapAction=${config.tapAction}`,'ok');
   } catch(e) { log(`Config write failed: ${e.message}`,'err'); }
 }
 
-// ── Individual control handlers ───────────────────────────────────────────────
+// Individual control handlers 
 // These update the local config shadow then write the full blob
 
 function setCurve(val) {
@@ -233,15 +344,31 @@ function setChargeMode(val) {
   config.chargeMode = val;
   setChargeModeUI(val);
   writeConfigBlob();
-  log(`Charge → ${['OFF','SLOW 50mA','FAST 100mA'][val]}`,'warn');
+  log(`Charge → ${['SLOW 50mA','FAST 100mA'][val]}`,'warn');
 }
 function setChargeModeUI(val) {
-  [['chgOff','off'],['chgSlow','slow'],['chgFast','fast']].forEach(([id,cls],i) => {
+  [['chgSlow','slow'],['chgFast','fast']].forEach(([id,cls],i) => {
     const b = document.getElementById(id);
-    b.classList.remove('active','off','slow','fast');
+    b.classList.remove('active','slow','fast');
     if (i===val) b.classList.add('active', cls);
   });
-  document.getElementById('ciMode').textContent = ['Off (0mA)','50 mA','100 mA'][val] ?? '--';
+  document.getElementById('ciMode').textContent = ['50 mA','100 mA'][val] ?? '--';
+}
+
+function onCapTapChange(enabled) {
+  writeConfigBlob();
+  log('Tap detection ' + (enabled ? 'enabled' : 'disabled') + ' - restart device to apply', 'warn');
+}
+
+function onTapFreezeChange(enabled) {
+  config.tapFreezeEnabled = enabled ? 1 : 0;
+  updateTapFreezeUI(enabled);
+  writeConfigBlob();
+}
+function updateTapFreezeUI(enabled) {
+  const slider = document.getElementById('slJerkThreshold');
+  // Only grey out when connected (on disconnect, setStatus handles all inputs)
+  if (device) slider.disabled = !enabled;
 }
 
 function setTapAction(val) {
@@ -263,7 +390,7 @@ function onTapKeyInput() {
 
 async function sendCalibrate() {
   if (!chars.command) return;
-  try { await gattCmd(chars.command, new Uint8Array([0x01])); log('Calibration sent — hold still!','warn'); }
+  try { await gattCmd(chars.command, new Uint8Array([0x01])); log('Calibration sent - hold still!','warn'); }
   catch(e) { log(`Calibrate failed: ${e.message}`,'err'); }
 }
 function confirmReset() { document.getElementById('overlay').classList.add('show'); }
@@ -277,25 +404,26 @@ async function doReset() {
   } catch(e) { log(`Reset failed: ${e.message}`,'err'); }
 }
 
-// ── Telemetry ────────────────────────────────────────────────────────────────
-// TelemetryPacket (24 bytes LE):
+// Telemetry 
+// TelemetryPacket (28 bytes LE - backwards compatible with 24-byte v3.3):
 //  uint32 uptime [0], uint32 leftClicks [4], uint32 rightClicks [8]
 //  float  temp   [12], float biasRms    [16]
 //  uint16 recalCount [20], uint8 chargeStatus [22], uint8 pad [23]
+//  float  battVoltage [24]  (new in v3.4, absent on older firmware)
 function parseTelemetry(dv) {
   let view;
   try {
     view = dv instanceof DataView ? new DataView(dv.buffer, dv.byteOffset, dv.byteLength) : new DataView(dv);
-  } catch(e) { log(`parseTelemetry: DataView wrap failed — ${e.message}`,'err'); return; }
+  } catch(e) { log(`parseTelemetry: DataView wrap failed - ${e.message}`,'err'); return; }
 
   if (view.byteLength < 24) {
     const bytes = new Uint8Array(view.buffer, view.byteOffset, view.byteLength);
     const hex = Array.from(bytes).map(b=>b.toString(16).padStart(2,'0')).join(' ');
-    log(`TELEM: expected 24B, got ${view.byteLength}B — MTU too small? raw: ${hex}`,'err');
+    log(`TELEM: expected 24-28B, got ${view.byteLength}B - MTU too small? raw: ${hex}`,'err');
     return;
   }
 
-  let uptime, leftClicks, rightClicks, temp, biasRms, recalCount, chargeStatus;
+  let uptime, leftClicks, rightClicks, temp, biasRms, recalCount, chargeStatus, battVoltage=null;
   try {
     uptime      = view.getUint32(0,  true);
     leftClicks  = view.getUint32(4,  true);
@@ -304,7 +432,8 @@ function parseTelemetry(dv) {
     biasRms     = view.getFloat32(16,true);
     recalCount  = view.getUint16(20, true);
     chargeStatus= view.getUint8(22);
-  } catch(e) { log(`parseTelemetry: parse error at offset — ${e.message}`,'err'); return; }
+    if (view.byteLength >= 28) battVoltage = view.getFloat32(24, true);
+  } catch(e) { log(`parseTelemetry: parse error at offset - ${e.message}`,'err'); return; }
 
   document.getElementById('telTemp').textContent   = temp.toFixed(1)+'°';
   document.getElementById('telUptime').textContent = formatUptime(uptime);
@@ -315,11 +444,17 @@ function parseTelemetry(dv) {
   const tEl = document.getElementById('telTemp');
   tEl.className = 'telem-val '+(temp>40?'warn':'accent');
 
-  // chargeStatus is now delivered via telemetry (no separate characteristic)
   if (chargeStatus !== currentChargeStatus) {
     currentChargeStatus = chargeStatus;
     updateChargeUI();
   }
+
+  if (battVoltage !== null) {
+    currentBattVoltage = battVoltage;
+    document.getElementById('ciVolt').textContent = battVoltage.toFixed(2) + 'V';
+    const pct = Math.round(Math.min(100, Math.max(0, (battVoltage - 3.00) / (4.20 - 3.00) * 100)));
+    if (pct !== currentBattPct) { currentBattPct = pct; updateBatteryBar(pct, currentChargeStatus); }
+  }
 }
 function formatUptime(s) {
   const h=Math.floor(s/3600), m=Math.floor((s%3600)/60), ss=s%60;
@@ -330,7 +465,7 @@ function clearTelemetry() {
     document.getElementById(id).textContent='--');
 }
 
-// ── Battery & Charge UI ───────────────────────────────────────────────────────
+// Battery & Charge UI 
 function updateBatteryBar(pct, status) {
   document.getElementById('battBar').style.display='flex';
   document.getElementById('battPct').textContent=pct+'%';
@@ -354,19 +489,125 @@ function updateChargeUI() {
   if (currentBattPct!==null) updateBatteryBar(currentBattPct, currentChargeStatus);
 }
 
-// ── Param display ─────────────────────────────────────────────────────────────
+// Advanced toggle 
+function toggleAdvanced(on) {
+  advancedMode = on;
+  localStorage.setItem('advanced', on);
+  document.getElementById('ciVoltItem').style.display = on ? '' : 'none';
+  document.getElementById('debugBtn').style.display = on ? '' : 'none';
+  // Switch charge-info grid between 3 and 4 columns
+  document.getElementById('chargeInfo').style.gridTemplateColumns = on ? '1fr 1fr 1fr 1fr' : '1fr 1fr 1fr';
+}
+
+// IMU Debug Recorder 
+let debugModalOpen = false;
+let debugRecording = false;
+let debugBuffer = [];
+const DEBUG_LIVE_ROWS = 40;
+let debugLiveRing = [];
+let debugT0 = 0;
+
+function openDebugModal() {
+  console.log('[DEBUG] modal opened (imuSubscribed=' + imuSubscribed + ')');
+  debugModalOpen = true;
+  debugT0 = Date.now();
+  debugLiveRing = [];
+  document.getElementById('debugOverlay').classList.add('show');
+  // Auto-start IMU stream if not already running
+  if (!imuSubscribed && chars.imuStream) vizSetPaused(false);
+}
+function closeDebugModal() {
+  console.log('[DEBUG] modal closed');
+  debugModalOpen = false;
+  document.getElementById('debugOverlay').classList.remove('show');
+}
+
+function feedDebugRow(gyroX, gyroZ, accelX, accelY, accelZ, moveX, moveY, flags) {
+  if (!debugModalOpen) return;
+  const ms = Date.now() - debugT0;
+  const row = { ms, gyroX, gyroZ, accelX, accelY, accelZ, moveX, moveY, flags };
+
+  // Live ring buffer
+  debugLiveRing.push(row);
+  if (debugLiveRing.length > DEBUG_LIVE_ROWS) debugLiveRing.shift();
+
+  // Recording buffer
+  if (debugRecording) {
+    debugBuffer.push(row);
+    document.getElementById('debugRecCount').textContent = debugBuffer.length + ' samples';
+  }
+
+  // Shock indicator
+  const shocked = !!(flags & 0x08);
+  const badge = document.getElementById('debugShockBadge');
+  badge.classList.toggle('active', shocked);
+
+  // Render live table
+  const tbody = document.getElementById('debugRows');
+  tbody.innerHTML = '';
+  for (const r of debugLiveRing) {
+    const f = [];
+    if (r.flags & 0x01) f.push('idle');
+    if (r.flags & 0x02) f.push('tap1');
+    if (r.flags & 0x04) f.push('tap2');
+    if (r.flags & 0x08) f.push('shock');
+    const tr = document.createElement('tr');
+    if (r.flags & 0x08) tr.className = 'shock-row';
+    tr.innerHTML =
+      `<td>${r.ms}</td><td>${r.gyroX}</td><td>${r.gyroZ}</td>` +
+      `<td>${r.accelX}</td><td>${r.accelY}</td><td>${r.accelZ}</td>` +
+      `<td>${r.moveX}</td><td>${r.moveY}</td><td>${f.join(' ')}</td>`;
+    tbody.appendChild(tr);
+  }
+  tbody.parentElement.parentElement.scrollTop = tbody.parentElement.parentElement.scrollHeight;
+}
+
+function toggleDebugRec() {
+  debugRecording = !debugRecording;
+  const btn = document.getElementById('debugRecBtn');
+  btn.classList.toggle('recording', debugRecording);
+  btn.textContent = debugRecording ? '■ STOP' : '● REC';
+  if (debugRecording) { debugBuffer = []; debugT0 = Date.now(); }
+  document.getElementById('debugRecCount').textContent = debugBuffer.length + ' samples';
+}
+
+function saveDebugCSV() {
+  if (!debugBuffer.length) { log('No recorded data to save','warn'); return; }
+  const header = 'ms,gyroX_mDPS,gyroZ_mDPS,accelX_mg,accelY_mg,accelZ_mg,moveX,moveY,flags\n';
+  const rows = debugBuffer.map(r =>
+    `${r.ms},${r.gyroX},${r.gyroZ},${r.accelX},${r.accelY},${r.accelZ},${r.moveX},${r.moveY},${r.flags}`
+  ).join('\n');
+  const blob = new Blob([header + rows], { type: 'text/csv' });
+  const url = URL.createObjectURL(blob);
+  const a = document.createElement('a');
+  a.href = url; a.download = `imu_debug_${new Date().toISOString().slice(0,19).replace(/:/g,'-')}.csv`;
+  a.click(); URL.revokeObjectURL(url);
+  log(`Saved ${debugBuffer.length} samples as CSV`,'ok');
+}
+
+function clearDebugRec() {
+  debugBuffer = [];
+  debugRecording = false;
+  const btn = document.getElementById('debugRecBtn');
+  btn.classList.remove('recording');
+  btn.textContent = '● REC';
+  document.getElementById('debugRecCount').textContent = '0 samples';
+}
+
+// Param display 
 function updateDisplay(key, val) {
   const map = {
     sensitivity:  ['valSensitivity',  v=>parseFloat(v).toFixed(0)],
     deadZone:     ['valDeadZone',     v=>parseFloat(v).toFixed(3)],
     accel:        ['valAccel',        v=>parseFloat(v).toFixed(2)],
+    jerkThreshold:['valJerkThreshold',v=>parseFloat(v).toFixed(0)],
     tapThreshold: ['valTapThreshold', v=>(parseFloat(v)*62.5).toFixed(0)+' mg'],
   };
   const [id,fmt] = map[key];
   document.getElementById(id).textContent = fmt(val);
 }
 
-// ── Status UI ────────────────────────────────────────────────────────────────
+// Status UI 
 function setStatus(state) {
   const pill=document.getElementById('statusPill');
   document.getElementById('statusText').textContent={connected:'CONNECTED',connecting:'CONNECTING…',disconnected:'DISCONNECTED'}[state];
@@ -388,12 +629,15 @@ function setStatus(state) {
 function onDisconnected() {
   log('Device disconnected','warn');
   const savedDevice = device;
+  gattQueueReset();
   chars={}; device=null; server=null;
   setStatus('disconnected');
   document.getElementById('battBar').style.display='none';
   document.getElementById('badgeCharging').classList.remove('show');
   document.getElementById('badgeFull').classList.remove('show');
-  imuSubscribed = false; vizPaused = true; vizUpdateIndicator();
+  imuSubscribed = false; vizPaused = true; vizUpdateIndicator(); streamDiagReset();
+  document.getElementById('orientLabel').textContent = '- not streaming -';
+  document.getElementById('hashMismatchBanner').style.display = 'none';
   clearTelemetry();
   if (!userDisconnected && document.getElementById('autoReconnect').checked && savedDevice) {
     log('Auto-reconnecting…','info');
@@ -414,9 +658,9 @@ function onDisconnected() {
   }
 }
 
-// ── IMU Stream + Visualiser ──────────────────────────────────────────────────
+// IMU Stream + Visualiser 
 // ImuPacket (14 bytes LE):
-//   int16 gyroY_mDPS [0], int16 gyroZ_mDPS [2]
+//  int16 gyroX_mDPS [0], int16 gyroZ_mDPS [2]
 //  int16 accelX_mg  [4], int16 accelY_mg  [6], int16 accelZ_mg [8]
 //  int8  moveX [10], int8 moveY [11], uint8 flags [12], uint8 pad [13]
 const canvas = document.getElementById('vizCanvas');
@@ -425,6 +669,55 @@ const TRAIL_LEN = 120;
 let cursorX = canvas.width/2, cursorY = canvas.height/2, trail = [];
 let vizPaused = true;
 let imuSubscribed = false;
+let _prevIdle = false;
+
+// Stream diagnostics 
+let streamPktCount  = 0;      // packets received this second
+let streamPktTotal  = 0;      // lifetime packet count
+let streamLastPktT  = 0;      // timestamp of last packet (for gap detection)
+let streamLastRateT = 0;      // timestamp of last rate log
+let streamFreezeTimer = null; // fires if no packet for >1s while subscribed
+
+function streamDiagReset() {
+  console.log('[STREAM] diagnostics reset');
+  streamPktCount = streamPktTotal = streamLastPktT = streamLastRateT = 0;
+  _prevIdle = false;
+  if (streamFreezeTimer) { clearTimeout(streamFreezeTimer); streamFreezeTimer = null; }
+}
+
+function streamDiagPkt() {
+  const now = Date.now();
+
+  // Gap detection - warn if >300ms since last packet while streaming
+  if (streamLastPktT) {
+    const gap = now - streamLastPktT;
+    if (gap > 300) log(`[STREAM] gap ${gap}ms (pkt #${streamPktTotal})`, 'warn');
+  }
+  streamLastPktT = now;
+  streamPktCount++;
+  streamPktTotal++;
+
+  // Reset freeze watchdog - 1.5s without a packet = freeze
+  if (streamFreezeTimer) clearTimeout(streamFreezeTimer);
+  streamFreezeTimer = setTimeout(() => {
+    log(`[STREAM] FROZEN - no packet for 1.5s (total rx: ${streamPktTotal})`, 'err');
+    streamFreezeTimer = null;
+  }, 1500);
+
+  // Log rate every 5s
+  if (streamLastRateT === 0) streamLastRateT = now;
+  if (now - streamLastRateT >= 5000) {
+    const rate = (streamPktCount / ((now - streamLastRateT) / 1000)).toFixed(1);
+    log(`[STREAM] ${rate} pkt/s · total ${streamPktTotal}`, 'info');
+    streamPktCount = 0;
+    streamLastRateT = now;
+  }
+}
+
+// Roll compensation is done entirely in firmware (calibrateGyroBias computes
+// rollSin/rollCos from boot-pose accel and applies the rotation before moveX/moveY).
+// The web visualiser just uses moveX/moveY directly - no re-rotation needed here.
+function resetOrient() {}  // kept for call-site compatibility
 
 function vizUpdateIndicator() {
   const el = document.getElementById('vizLive');
@@ -444,26 +737,32 @@ function vizUpdateIndicator() {
 async function vizSetPaused(paused) {
   vizPaused = paused;
   if (!paused && chars.imuStream && !imuSubscribed) {
+    console.log('[STREAM] requesting subscribe');
     try {
       await chars.imuStream.startNotifications();
       imuSubscribed = true;
+      document.getElementById('orientLabel').textContent = 'roll correction active (firmware)';
       log('IMU stream subscribed','ok');
     } catch(e) { log(`IMU stream start failed: ${e.message}`,'err'); vizPaused = true; }
   } else if (paused && imuSubscribed) {
+    console.log(`[STREAM] requesting unsubscribe (total rx: ${streamPktTotal})`);
     try {
       await chars.imuStream.stopNotifications();
       imuSubscribed = false;
+      streamDiagReset();
+      document.getElementById('orientLabel').textContent = '- not streaming -';
     } catch(e) { log(`IMU stream stop failed: ${e.message}`,'err'); }
+  } else {
+    console.log(`[STREAM] vizSetPaused(${paused}) - no action (imuSubscribed=${imuSubscribed})`);
   }
   vizUpdateIndicator();
 }
 
 function parseImuStream(dv) {
-  if (vizPaused) return;
   let view;
   try {
     view = dv instanceof DataView ? new DataView(dv.buffer, dv.byteOffset, dv.byteLength) : new DataView(dv);
-  } catch(e) { log(`parseImuStream: DataView wrap failed — ${e.message}`,'err'); return; }
+  } catch(e) { log(`parseImuStream: DataView wrap failed - ${e.message}`,'err'); return; }
 
   if (view.byteLength < 14) {
     const bytes = new Uint8Array(view.buffer, view.byteOffset, view.byteLength);
@@ -472,31 +771,53 @@ function parseImuStream(dv) {
     return;
   }
 
-  let gyroY, gyroZ, moveX, moveY, flags;
+  let gyroX, gyroZ, accelX, accelY, accelZ, moveX, moveY, flags;
   try {
-    gyroY = view.getInt16(0, true);
-    gyroZ = view.getInt16(2, true);
+    gyroX  = view.getInt16(0, true);  // GX = pitch axis (nod → cursor Y)
+    gyroZ  = view.getInt16(2, true);  // GZ = yaw axis   (pan → cursor X)
+    accelX = view.getInt16(4, true);
+    accelY = view.getInt16(6, true);
+    accelZ = view.getInt16(8, true);
     moveX  = view.getInt8(10);
     moveY  = view.getInt8(11);
     flags  = view.getUint8(12);
-  } catch(e) { log(`parseImuStream: parse error — ${e.message}`,'err'); return; }
+  } catch(e) { log(`parseImuStream: parse error - ${e.message}`,'err'); return; }
+
+  // Feed debug recorder (even when viz is paused)
+  feedDebugRow(gyroX, gyroZ, accelX, accelY, accelZ, moveX, moveY, flags);
+
+  if (vizPaused) return;
+
   const idle   = !!(flags & 0x01);
   const single = !!(flags & 0x02);
   const dbl    = !!(flags & 0x04);
 
-  updateAxisBar('gy', gyroY, 30000);
-  updateAxisBar('gz', gyroZ, 30000);
+  // Axis bars: show raw gyro (firmware convention: Z→screen-X, X→screen-Y)
+  updateAxisBar('gy', -gyroZ, 30000);
+  updateAxisBar('gz', -gyroX, 30000);
 
   if (!idle) {
+    // moveX/moveY are already roll-corrected by firmware - use them directly
     cursorX = Math.max(4, Math.min(canvas.width  - 4, cursorX + moveX * 1.5));
     cursorY = Math.max(4, Math.min(canvas.height - 4, cursorY + moveY * 1.5));
   }
   trail.push({x:cursorX, y:cursorY, t:Date.now(), idle});
   if (trail.length > TRAIL_LEN) trail.shift();
 
+  streamDiagPkt();
+
+  if (idle !== _prevIdle) {
+    console.log(`[STREAM] idle → ${idle ? 'idle' : 'active'} (pkt #${streamPktTotal})`);
+    _prevIdle = idle;
+  }
+  if (single) console.log(`[STREAM] single tap (pkt #${streamPktTotal})`);
+  if (dbl)    console.log(`[STREAM] double tap (pkt #${streamPktTotal})`);
+
   if (single) flashTap('Left');
   if (dbl)    flashTap('Right');
   drawViz(idle);
+
+  orientFeedIMU(accelX, accelY, accelZ, gyroX, gyroZ);
 }
 
 function updateAxisBar(axis, val, max) {
@@ -551,7 +872,114 @@ function drawInitState() {
   ctx.fillStyle=cssVar('--canvas-idle-text');ctx.font='10px Share Tech Mono,monospace';
   ctx.textAlign='center';ctx.fillText('connect to activate stream',W/2,H/2+4);ctx.textAlign='left';
 }
-// ── Theme ─────────────────────────────────────────────────────────────────────
+// 3D Orientation Viewer 
+// Device box: L=115mm (X), W=36mm (Y), H=20mm (Z)
+// Complementary filter mirrors firmware: α=0.96, dt from packet rate (~50ms)
+const ORIENT_ALPHA = 0.96;
+const DEVICE_L = 1.15, DEVICE_W = 0.36, DEVICE_H = 0.20;  // metres (Three.js units)
+
+let orientScene, orientCamera, orientRenderer, orientMesh, orientEdges;
+let orientQ = new THREE.Quaternion();   // current estimated orientation
+let orientLastT = 0;
+
+function initOrientViewer() {
+  const el = document.getElementById('orientCanvas');
+  const W = el.clientWidth || 340, H = el.clientHeight || W;
+  el.width = W; el.height = H;
+
+  orientScene    = new THREE.Scene();
+  orientCamera   = new THREE.PerspectiveCamera(55, W / H, 0.01, 10);
+  orientCamera.position.set(0.75, 0.60, 1.10);
+  orientCamera.lookAt(0, 0, 0);
+
+  orientRenderer = new THREE.WebGLRenderer({ canvas: el, antialias: true, alpha: true });
+  orientRenderer.setSize(W, H);
+  orientRenderer.setClearColor(0x000000, 0);
+
+  // Box geometry
+  const geo  = new THREE.BoxGeometry(DEVICE_L, DEVICE_H, DEVICE_W);
+  const mat  = new THREE.MeshPhongMaterial({
+    color: 0x1a2230, emissive: 0x050a10, specular: 0x00e5ff,
+    shininess: 60, transparent: true, opacity: 0.85,
+  });
+  orientMesh = new THREE.Mesh(geo, mat);
+  orientScene.add(orientMesh);
+
+  // Wireframe edges
+  const edgeMat = new THREE.LineBasicMaterial({ color: 0x00e5ff, linewidth: 1 });
+  orientEdges = new THREE.LineSegments(new THREE.EdgesGeometry(geo), edgeMat);
+  orientMesh.add(orientEdges);
+
+  // "Front" face marker - small arrow along +X (length axis)
+  const arrowGeo = new THREE.ConeGeometry(0.02, 0.07, 6);
+  arrowGeo.rotateZ(-Math.PI / 2);
+  arrowGeo.translate(DEVICE_L / 2 + 0.04, 0, 0);
+  const arrowMesh = new THREE.Mesh(arrowGeo,
+    new THREE.MeshBasicMaterial({ color: 0x00e5ff }));
+  orientMesh.add(arrowMesh);
+
+  // Lighting
+  orientScene.add(new THREE.AmbientLight(0xffffff, 0.4));
+  const dlight = new THREE.DirectionalLight(0xffffff, 0.9);
+  dlight.position.set(1, 2, 2);
+  orientScene.add(dlight);
+
+  orientRenderer.render(orientScene, orientCamera);
+}
+
+function orientUpdateColors() {
+  // Re-read CSS variables so it adapts to theme changes
+  const accent = cssVar('--accent').replace('#','');
+  const c = parseInt(accent, 16);
+  if (orientEdges) orientEdges.material.color.setHex(c);
+}
+
+function orientFeedIMU(ax, ay, az, gyX_mDPS, gyZ_mDPS) {
+  if (!orientRenderer) return;
+  const now = Date.now();
+  const dt  = orientLastT ? Math.min((now - orientLastT) / 1000, 0.1) : 0.05;
+  orientLastT = now;
+
+  // Accel in g (packet is in mg)
+  const axG = ax / 1000, ayG = ay / 1000, azG = az / 1000;
+  const aNorm = Math.sqrt(axG*axG + ayG*ayG + azG*azG);
+
+  // Accel-derived quaternion (gravity reference). LSM6DS3 axes:
+  // device flat, face up: az ≈ +1g
+  // Pitch (tilt front up): ay changes; Roll (tilt right side up): ax changes
+  let qAccel = new THREE.Quaternion();
+  if (aNorm > 0.5 && aNorm < 2.0) {
+    // gravity unit vector in device frame
+    const gx = axG / aNorm, gy = ayG / aNorm, gz = azG / aNorm;
+    // Align device -Z (down face) with gravity
+    const up = new THREE.Vector3(0, 1, 0);          // Three.js world up
+    const gVec = new THREE.Vector3(-gx, -gz, gy);   // map device→Three axes
+    gVec.normalize();
+    qAccel.setFromUnitVectors(gVec, up);
+  } else {
+    qAccel.copy(orientQ);
+  }
+
+  // Gyro integration - firmware sends gyroX (pitch) and gyroZ (yaw), mDPS
+  // Map to Three.js axes: gyroZ→world Y, gyroX→world X
+  const gyRad = gyX_mDPS * (Math.PI / 180) / 1000;
+  const gzRad = gyZ_mDPS * (Math.PI / 180) / 1000;
+  const dq = new THREE.Quaternion(
+    gyRad * dt * 0.5,   // x
+    -gzRad * dt * 0.5,  // y
+    0, 1
+  ).normalize();
+  const qGyro = orientQ.clone().multiply(dq);
+
+  // Complementary filter
+  orientQ.copy(qGyro).slerp(qAccel, 1 - ORIENT_ALPHA);
+  orientQ.normalize();
+
+  orientMesh.quaternion.copy(orientQ);
+  orientRenderer.render(orientScene, orientCamera);
+}
+
+// Theme 
 const THEMES = ['auto','dark','light'];
 const THEME_LABELS = {auto:'AUTO',dark:'DARK',light:'LIGHT'};
 let themeIdx = 0;
@@ -567,11 +995,16 @@ function applyTheme(t) {
   document.getElementById('themeBtn').querySelector('span').textContent = THEME_LABELS[t];
   localStorage.setItem('theme', t);
   if (!chars.imuStream) drawInitState();
+  orientUpdateColors();
 }
 (function(){
   const saved = localStorage.getItem('theme') ?? 'auto';
   themeIdx = Math.max(0, THEMES.indexOf(saved));
   applyTheme(saved);
+  initOrientViewer();
+  // Restore advanced toggle state
+  document.getElementById('advancedToggle').checked = advancedMode;
+  if (advancedMode) toggleAdvanced(true);
 })();
 
 if (!navigator.bluetooth) {
@@ -579,3 +1012,35 @@ if (!navigator.bluetooth) {
 } else {
   log('Web Bluetooth ready. Click CONNECT to pair your IMU Mouse.','info');
 }
+
+// ─────────────────────────────────────────────────────────────────────────────
+//  OTA firmware update
+//
+//  The OTAFIX bootloader uses Nordic Legacy DFU (service 00001530-...) which is
+//  blocklisted in Chrome's Web Bluetooth implementation.  Browser-side upload is
+//  therefore not possible without special flags or a native app wrapper.
+//
+//  What the UI does instead:
+//    • "Enter DFU Mode" sends command 0x02 via BLE → device reboots as XIAO_DFU
+//    • User then uploads firmware_dfu.zip via nRF Connect (mobile or desktop)
+// ─────────────────────────────────────────────────────────────────────────────
+
+function otaLog(msg, type = 'info') {
+  log('[OTA] ' + msg, type);
+  const el = document.getElementById('otaStatus');
+  if (el) { el.textContent = msg; el.className = 'ota-status' + (type !== 'info' ? ' ota-' + type : ''); }
+}
+
+// Send command 0x02 → firmware reboots into XIAO_DFU bootloader mode.
+// User then uploads firmware_dfu.zip via nRF Connect.
+async function sendOTATrigger() {
+  if (!chars.command) { otaLog('Not connected', 'err'); return; }
+  document.getElementById('btnOTA').disabled = true;
+  try {
+    await chars.command.writeValueWithResponse(new Uint8Array([0x02]));
+    otaLog('Device rebooting into DFU mode — connect to XIAO_DFU in nRF Connect', 'ok');
+  } catch (e) {
+    otaLog('Failed: ' + e.message, 'err');
+    document.getElementById('btnOTA').disabled = false;
+  }
+}

web/index.html

@@ -6,9 +6,13 @@
 <title>IMU Mouse // Config Terminal</title>
 <link href="https://fonts.googleapis.com/css2?family=Share+Tech+Mono&family=Barlow+Condensed:wght@300;400;600;700;900&display=swap" rel="stylesheet">
 <link rel="stylesheet" href="style.css">
+<script src="https://cdn.jsdelivr.net/npm/three@0.128.0/build/three.min.js"></script>
+<script src="version.js"></script>
 </head>
 <body class="disconnected">
 
+<div id="hashMismatchBanner" style="display:none"></div>
+
 <header>
   <div>
     <div class="logo">IMU<span>·</span>Mouse</div>
@@ -21,16 +25,21 @@
       <div class="batt-cells" id="battCells"></div>
       <span id="battPct">--%</span>
     </div>
+    <button class="btn btn-debug" id="debugBtn" onclick="openDebugModal()" style="display:none" title="IMU Debug Recorder"><span>DBG</span></button>
     <button class="btn btn-theme" id="themeBtn" onclick="cycleTheme()"><span>AUTO</span></button>
     <div class="status-pill" id="statusPill"><div class="dot"></div><span id="statusText">DISCONNECTED</span></div>
     <button class="btn btn-connect"    id="connectBtn"    onclick="doConnect()"><span>Connect</span></button>
     <button class="btn btn-disconnect" id="disconnectBtn" onclick="doDisconnect()" style="display:none"><span>Disconnect</span></button>
     <label class="toggle" title="Auto-Reconnect" style="margin-left:6px;flex-shrink:0"><input type="checkbox" id="autoReconnect"><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
     <span style="font-family:var(--mono);font-size:9px;color:var(--label);white-space:nowrap">AUTO-RECONNECT</span>
+    <label class="toggle" style="margin-left:10px;flex-shrink:0" title="Advanced"><input type="checkbox" id="advancedToggle" onchange="toggleAdvanced(this.checked)"><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
+    <span style="font-family:var(--mono);font-size:9px;color:var(--label);white-space:nowrap">ADVANCED</span>
   </div>
 </header>
 
 <main id="mainContent">
+
+  <!--  col-left: cursor motion  -->
   <div class="col-left">
 
     <div class="section-label">Motion Parameters</div>
@@ -42,7 +51,7 @@
         <div class="param-value" id="valSensitivity">600</div>
       </div>
       <div class="param">
-        <div><div class="param-label">Dead Zone</div><div class="param-desc">Noise floor (rad/s) — raise to reduce drift</div></div>
+        <div><div class="param-label">Dead Zone</div><div class="param-desc">Noise floor (rad/s) - raise to reduce drift</div></div>
         <input type="range" id="slDeadZone" min="0.005" max="0.2" step="0.005" value="0.06"
           oninput="updateDisplay('deadZone',this.value)" onchange="writeConfigBlob()">
         <div class="param-value" id="valDeadZone">0.060</div>
@@ -77,20 +86,70 @@
       <div class="param" style="border-bottom:none;padding:0">
         <div><div class="param-label">Charge Mode</div><div class="param-desc">BQ25100 ISET via P0.13 (HICHG)</div></div>
         <div class="segmented charge-seg" style="grid-column:2/4">
-          <button class="seg-btn off"  id="chgOff"  onclick="setChargeMode(0)" disabled>OFF</button>
-          <button class="seg-btn slow" id="chgSlow" onclick="setChargeMode(1)" disabled>SLOW · 50mA</button>
-          <button class="seg-btn fast" id="chgFast" onclick="setChargeMode(2)" disabled>FAST · 100mA</button>
+          <button class="seg-btn slow" id="chgSlow" onclick="setChargeMode(0)" disabled>SLOW · 50mA</button>
+          <button class="seg-btn fast" id="chgFast" onclick="setChargeMode(1)" disabled>FAST · 100mA</button>
         </div>
       </div>
-      <div class="charge-info">
+      <div class="charge-info" id="chargeInfo">
         <div class="ci-item"><div class="ci-val" id="ciStatus">--</div><div class="ci-lbl">Status</div></div>
         <div class="ci-item"><div class="ci-val" id="ciMode">--</div><div class="ci-lbl">Current</div></div>
         <div class="ci-item"><div class="ci-val" id="ciPct">--%</div><div class="ci-lbl">Level</div></div>
+        <div class="ci-item ci-advanced" id="ciVoltItem" style="display:none"><div class="ci-val accent" id="ciVolt">--</div><div class="ci-lbl">Voltage</div></div>
       </div>
     </div>
 
+    <div class="section-label">Axis Configuration</div>
+    <div class="card">
+      <div class="flip-row">
+        <div class="flip-label">Flip X Axis</div>
+        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Invert left / right</div>
+        <label class="toggle"><input type="checkbox" id="flipX" onchange="writeConfigBlob()" disabled><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
+      </div>
+      <div class="flip-row" style="border-bottom:none">
+        <div class="flip-label">Flip Y Axis</div>
+        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Invert up / down</div>
+        <label class="toggle"><input type="checkbox" id="flipY" onchange="writeConfigBlob()" disabled><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
+      </div>
+    </div>
+
+    <div class="section-label">Device Capabilities</div>
+    <div class="card">
+      <div class="flip-row">
+        <div class="flip-label">Tap Detection</div>
+        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Double-tap click action &nbsp;<span class="restart-note">· restart to apply</span></div>
+        <label class="toggle"><input type="checkbox" id="capTapEnabled" onchange="onCapTapChange(this.checked)" disabled><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
+      </div>
+      <div class="flip-row">
+        <div class="flip-label">Temp Compensation</div>
+        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Gyro drift correction by temperature</div>
+        <label class="toggle"><input type="checkbox" id="capTempComp" onchange="writeConfigBlob()" disabled><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
+      </div>
+      <div class="flip-row" style="border-bottom:none">
+        <div class="flip-label">Auto Recalibration</div>
+        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Recalibrate gyro after long idle period</div>
+        <label class="toggle"><input type="checkbox" id="capAutoRecal" onchange="writeConfigBlob()" disabled><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
+      </div>
+    </div>
+
+  </div><!-- /col-left -->
+
+  <!--  col-mid: button configuration  -->
+  <div class="col-mid">
+
     <div class="section-label">Tap Configuration</div>
     <div class="card">
+      <div class="param">
+        <div><div class="param-label">Tap Freeze</div><div class="param-desc">Freeze cursor during tap impacts (jerk detection)</div></div>
+        <div style="grid-column:2/4;display:flex;justify-content:flex-end;align-items:center">
+          <label class="toggle"><input type="checkbox" id="tapFreezeEnabled" onchange="onTapFreezeChange(this.checked)" disabled><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
+        </div>
+      </div>
+      <div class="param">
+        <div><div class="param-label">Tap Freeze Sensitivity</div><div class="param-desc">Jerk² threshold - lower = more aggressive cursor freeze during taps</div></div>
+        <input type="range" id="slJerkThreshold" min="500" max="10000" step="100" value="2000"
+          oninput="updateDisplay('jerkThreshold',this.value)" onchange="writeConfigBlob()">
+        <div class="param-value" id="valJerkThreshold">2000</div>
+      </div>
       <div class="param">
         <div><div class="param-label">Tap Threshold</div><div class="param-desc">Impact force needed · 1 LSB ≈ 62.5 mg at ±2g</div></div>
         <input type="range" id="slTapThreshold" min="1" max="31" step="1" value="12"
@@ -121,25 +180,11 @@
       </div>
     </div>
 
-    <div class="section-label">Axis Configuration</div>
-    <div class="card">
-      <div class="flip-row">
-        <div class="flip-label">Flip X Axis</div>
-        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Invert left / right</div>
-        <label class="toggle"><input type="checkbox" id="flipX" onchange="writeConfigBlob()" disabled><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
-      </div>
-      <div class="flip-row" style="border-bottom:none">
-        <div class="flip-label">Flip Y Axis</div>
-        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Invert up / down</div>
-        <label class="toggle"><input type="checkbox" id="flipY" onchange="writeConfigBlob()" disabled><div class="toggle-track"></div><div class="toggle-thumb"></div></label>
-      </div>
-    </div>
-
     <div class="section-label">Device Commands</div>
     <div class="cmd-grid">
       <button class="cmd-btn calibrate" id="btnCal" onclick="sendCalibrate()" disabled>
         <span class="cmd-icon">⊕</span><span>Calibrate Gyro</span>
-        <span class="cmd-desc">Hold device still — recalculates bias + records cal temperature.</span>
+        <span class="cmd-desc">Hold device still - recalculates bias + records cal temperature.</span>
       </button>
       <button class="cmd-btn reset" id="btnReset" onclick="confirmReset()" disabled>
         <span class="cmd-icon">⚠</span><span>Factory Reset</span>
@@ -147,11 +192,35 @@
       </button>
     </div>
 
+    <div class="section-label" style="margin-top:8px">Firmware Update (OTA)</div>
+    <div class="card ota-card" id="otaCard">
+      <div class="ota-notice">
+        <div class="ota-notice-icon">⚠</div>
+        <div>
+          <div class="ota-notice-title">Browser OTA not available</div>
+          <div class="ota-notice-body">Chrome blocks the Nordic Legacy DFU service UUID used by this bootloader. Use <strong>nRF Connect</strong> (mobile or desktop) to upload firmware instead.</div>
+        </div>
+      </div>
+      <ol class="ota-steps">
+        <li>Build firmware: <code>pio run</code> → produces <code>firmware_dfu.zip</code></li>
+        <li>Click <strong>Enter DFU Mode</strong> below — device reboots as <em>XIAO_DFU</em></li>
+        <li>Open nRF Connect → connect to <em>XIAO_DFU</em> → DFU → select <code>firmware_dfu.zip</code></li>
+      </ol>
+      <div class="ota-btn-row" style="grid-template-columns:1fr">
+        <button class="cmd-btn ota-trigger" id="btnOTA" onclick="sendOTATrigger()" disabled>
+          <span class="cmd-icon">⟳</span><span>Enter DFU Mode</span>
+          <span class="cmd-desc">Reboots device into XIAO_DFU so nRF Connect can upload firmware.</span>
+        </button>
+      </div>
+      <div class="ota-status-row"><div class="ota-status" id="otaStatus"></div></div>
+    </div>
+
     <div class="section-label" style="margin-top:8px">Event Log</div>
     <div class="console" id="console"></div>
 
-  </div>
+  </div><!-- /col-mid -->
 
+  <!--  col-right: live monitoring  -->
   <div class="col-right">
 
     <div class="section-label">Live Cursor Visualiser</div>
@@ -171,11 +240,11 @@
       </div>
       <div class="viz-axes">
         <div class="axis-bar-wrap">
-          <div class="axis-bar-label"><span>GY (up/down)</span><span id="gyVal">0</span></div>
+          <div class="axis-bar-label"><span>X (left/right)</span><span id="gyVal">0</span></div>
           <div class="axis-bar-track"><div class="axis-bar-fill" id="gyBar"></div><div class="axis-bar-center"></div></div>
         </div>
         <div class="axis-bar-wrap">
-          <div class="axis-bar-label"><span>GZ (left/right)</span><span id="gzVal">0</span></div>
+          <div class="axis-bar-label"><span>Y (up/down)</span><span id="gzVal">0</span></div>
           <div class="axis-bar-track"><div class="axis-bar-fill" id="gzBar"></div><div class="axis-bar-center"></div></div>
         </div>
       </div>
@@ -184,6 +253,12 @@
       </div>
     </div>
 
+    <div class="section-label">Device Orientation</div>
+    <div class="card orient-card">
+      <canvas id="orientCanvas"></canvas>
+      <div style="font-size:9px;color:var(--label);text-align:center;margin-top:6px" id="orientLabel">- not streaming -</div>
+    </div>
+
     <div class="section-label">Live Telemetry</div>
     <div class="telem-grid">
       <div class="telem-cell"><div class="telem-val accent" id="telTemp">--</div><div class="telem-lbl">Temperature °C</div></div>
@@ -197,6 +272,7 @@
   </div>
 </main>
 
+
 <div class="overlay" id="overlay">
   <div class="modal">
     <h3>⚠ Factory Reset</h3>
@@ -208,6 +284,32 @@
   </div>
 </div>
 
+<div class="overlay" id="debugOverlay">
+  <div class="modal debug-modal">
+    <div class="debug-header">
+      <h3>IMU Debug Recorder</h3>
+      <div style="display:flex;align-items:center;gap:8px">
+        <span class="debug-shock-badge" id="debugShockBadge">SHOCK</span>
+        <button class="debug-close" onclick="closeDebugModal()">✕</button>
+      </div>
+    </div>
+    <div class="debug-live" id="debugLive">
+      <table class="debug-table">
+        <thead><tr>
+          <th>ms</th><th>gX</th><th>gZ</th><th>aX</th><th>aY</th><th>aZ</th><th>mX</th><th>mY</th><th>flags</th>
+        </tr></thead>
+        <tbody id="debugRows"></tbody>
+      </table>
+    </div>
+    <div class="debug-controls">
+      <button class="debug-rec-btn" id="debugRecBtn" onclick="toggleDebugRec()">● REC</button>
+      <span class="debug-rec-count" id="debugRecCount">0 samples</span>
+      <button class="debug-ctrl-btn" onclick="saveDebugCSV()">Save CSV</button>
+      <button class="debug-ctrl-btn" onclick="clearDebugRec()">Clear</button>
+    </div>
+  </div>
+</div>
+
 <script src="app.js"></script>
 </body>
 </html>

web/style.css

@@ -34,7 +34,7 @@
     --tap-right:        rgba(255,61,113,0.35);
   }
 
-  /* ── Light theme (explicit) ──────────────────────────────────────────────── */
+  /*  Light theme (explicit)  */
   :root.theme-light {
     --bg:      #f0f2f5;
     --panel:   #ffffff;
@@ -66,7 +66,7 @@
   }
 
 
-  /* ── Auto light (OS hint; explicit class overrides) ──────────────────────── */
+  /*  Auto light (OS hint; explicit class overrides)  */
   @media (prefers-color-scheme: light) {
     :root:not(.theme-dark) {
       --bg:      #f0f2f5;
@@ -110,7 +110,7 @@
   .logo-sub { font-size:10px; color:var(--label); letter-spacing:0.25em; text-transform:uppercase; margin-top:3px; }
   .header-right { margin-left:auto; display:flex; align-items:center; gap:10px; flex-wrap:wrap; justify-content:flex-end; }
 
-  .status-pill { display:flex; align-items:center; gap:8px; padding:6px 12px; border:1px solid var(--border); font-size:11px; letter-spacing:0.15em; text-transform:uppercase; color:var(--label); transition:all 0.3s; white-space:nowrap; }
+  .status-pill { display:flex; align-items:center; gap:8px; height:34px; padding:0 14px; border:1px solid var(--border); font-size:11px; letter-spacing:0.15em; text-transform:uppercase; color:var(--label); transition:all 0.3s; white-space:nowrap; }
   .status-pill.connected  { border-color:var(--ok);   color:var(--ok); }
   .status-pill.connecting { border-color:var(--warn); color:var(--warn); }
   .dot { width:7px; height:7px; border-radius:50%; background:var(--dim); flex-shrink:0; }
@@ -131,6 +131,8 @@
   .btn:disabled { border-color:var(--dim); color:var(--dim); cursor:not-allowed; }
   .btn:disabled::before { display:none; }
   .btn:disabled:hover { color:var(--dim); }
+  .btn-debug { border:1px solid var(--dim); color:var(--label); min-width:52px; text-align:center; font-size:10px; height:34px; padding:0 10px; }
+  .btn-debug::before { background:var(--accent); }
   .btn-theme { border:1px solid var(--dim); color:var(--label); min-width:72px; text-align:center; }
   .btn-theme::before { background:var(--text); }
 
@@ -146,10 +148,25 @@
   .chg-badge.full     { border-color:var(--ok);     color:var(--ok); }
   .chg-badge.show     { display:flex; }
 
-  main { max-width:1100px; margin:0 auto; padding:32px 20px 80px; display:grid; grid-template-columns:1fr 380px; gap:16px; align-items:start; }
+  main { max-width:1440px; margin:0 auto; padding:32px 20px 80px; display:grid; grid-template-columns:1fr 1fr 380px; gap:16px; align-items:start; }
   .col-left  { display:grid; gap:12px; }
+  .col-mid   { display:grid; gap:12px; }
   .col-right { display:grid; gap:12px; position:sticky; top:80px; }
 
+
+  /*  Responsive  */
+  @media (max-width:1100px) {
+    main { grid-template-columns:1fr 380px; grid-template-rows:auto auto; }
+    .col-left  { grid-column:1; grid-row:1; }
+    .col-mid   { grid-column:1; grid-row:2; }
+    .col-right { grid-column:2; grid-row:1/3; }
+  }
+  @media (max-width:700px) {
+    main { grid-template-columns:1fr; }
+    .col-left, .col-mid, .col-right { grid-column:1; grid-row:auto; }
+    .col-right { position:static; }
+  }
+
   .section-label { font-family:var(--sans); font-size:11px; font-weight:600; letter-spacing:0.3em; text-transform:uppercase; color:var(--label); padding:4px 0; border-bottom:1px solid var(--border); margin-bottom:4px; display:flex; align-items:center; gap:8px; }
   .section-label::before { content:'//'; color:var(--accent); font-family:var(--mono); font-size:10px; }
 
@@ -175,7 +192,6 @@
   .seg-btn:last-child { border-right:none; }
   .seg-btn.active { background:var(--accent); color:var(--bg); font-weight:bold; }
   .seg-btn:disabled { cursor:not-allowed; opacity:0.35; }
-  .charge-seg .seg-btn.active.off  { background:var(--dim);    color:#fff; }
   .charge-seg .seg-btn.active.slow { background:var(--warn);   color:var(--bg); }
   .charge-seg .seg-btn.active.fast { background:var(--accent2);color:#fff; }
 
@@ -222,6 +238,8 @@
   .viz-panel { background:var(--panel2); border:1px solid var(--border); padding:16px; }
   .viz-header { display:flex; justify-content:space-between; align-items:center; margin-bottom:12px; }
   .viz-title { font-family:var(--sans); font-size:11px; font-weight:600; letter-spacing:0.25em; text-transform:uppercase; color:var(--label); }
+  .orient-card { padding:12px; display:flex; flex-direction:column; align-items:center; }
+  #orientCanvas { display:block; width:100%; aspect-ratio:1; }
   .viz-ctrl-btn { background:none; border:1px solid var(--border); color:var(--label); font-size:11px; line-height:1; padding:3px 8px; cursor:pointer; letter-spacing:0.05em; }
   .viz-ctrl-btn:hover { border-color:var(--accent); color:var(--accent); }
   .viz-live { font-size:9px; letter-spacing:0.2em; display:block; }
@@ -262,11 +280,35 @@
   .btn-confirm { border-color:var(--accent2); color:var(--accent2); }
   .btn-confirm:hover { background:var(--accent2); color:var(--bg); }
 
+  /*  Debug modal  */
+  .debug-modal { max-width:720px; padding:20px; border-color:var(--accent); }
+  .debug-modal h3 { color:var(--accent); margin-bottom:0; }
+  .debug-header { display:flex; justify-content:space-between; align-items:center; margin-bottom:14px; }
+  .debug-close { background:none; border:1px solid var(--border); color:var(--label); font-size:14px; cursor:pointer; padding:2px 8px; font-family:var(--mono); }
+  .debug-close:hover { border-color:var(--text); color:var(--text); }
+  .debug-live { max-height:340px; overflow-y:auto; border:1px solid var(--border); margin-bottom:12px; }
+  .debug-table { width:100%; border-collapse:collapse; font-family:var(--mono); font-size:10px; }
+  .debug-table thead { position:sticky; top:0; background:var(--panel); z-index:1; }
+  .debug-table th { padding:4px 6px; text-align:right; color:var(--label); font-weight:400; border-bottom:1px solid var(--border); letter-spacing:0.1em; text-transform:uppercase; }
+  .debug-table td { padding:2px 6px; text-align:right; color:var(--text); border-bottom:1px solid color-mix(in srgb, var(--border) 40%, transparent); white-space:nowrap; }
+  .debug-table td:last-child { text-align:left; color:var(--label); }
+  .debug-table .shock-row td { color:var(--accent2); }
+  .debug-controls { display:flex; align-items:center; gap:10px; }
+  .debug-rec-btn { font-family:var(--mono); font-size:12px; font-weight:700; padding:6px 14px; cursor:pointer; border:1px solid var(--accent2); color:var(--accent2); background:transparent; letter-spacing:0.1em; }
+  .debug-rec-btn.recording { background:var(--accent2); color:var(--bg); animation:rec-pulse 1s infinite; }
+  @keyframes rec-pulse { 0%,100%{opacity:1} 50%{opacity:0.6} }
+  .debug-rec-count { font-family:var(--mono); font-size:10px; color:var(--label); }
+  .debug-ctrl-btn { font-family:var(--mono); font-size:10px; padding:5px 10px; cursor:pointer; border:1px solid var(--border); color:var(--label); background:transparent; }
+  .debug-ctrl-btn:hover { border-color:var(--text); color:var(--text); }
+  .debug-shock-badge { font-family:var(--mono); font-size:9px; letter-spacing:0.15em; padding:2px 8px; border:1px solid var(--border); color:var(--border); opacity:0.3; transition:all 0.15s; }
+  .debug-shock-badge.active { border-color:var(--accent2); color:var(--accent2); opacity:1; }
+
   .no-ble { grid-column:1/-1; text-align:center; padding:80px 24px; }
   .no-ble h2 { font-family:var(--sans); font-size:28px; font-weight:700; color:var(--accent2); margin-bottom:12px; }
   .no-ble p { font-size:13px; color:var(--label); line-height:1.8; }
 
   body.disconnected .card { opacity:0.45; pointer-events:none; transition:opacity 0.3s; }
+  body.disconnected .card.ota-card { opacity:1; pointer-events:auto; }  /* OTA works when disconnected too */
   body.disconnected .cmd-grid { opacity:0.45; pointer-events:none; transition:opacity 0.3s; }
 
   .tap-key-row { display:flex; align-items:center; gap:10px; padding-top:12px; flex-wrap:wrap; }
@@ -276,8 +318,29 @@
   .mod-btn input:checked + span { background:var(--accent); color:var(--bg); border-color:var(--accent); font-weight:bold; }
   .mod-btn input:disabled + span { opacity:0.35; cursor:not-allowed; }
 
+  .restart-note { color:var(--warn); font-family:var(--mono); font-size:9px; }
+
+
   .tap-flash { position:absolute; inset:0; pointer-events:none; opacity:0; transition:opacity 0.25s; }
   .tap-flash.left { background:radial-gradient(circle at center, var(--tap-left)  0%, transparent 70%); }
   .tap-flash.right { background:radial-gradient(circle at center, var(--tap-right) 0%, transparent 70%); }
   .tap-flash.show { opacity:1; }
   .viz-wrap { position:relative; }
+
+  /* ── OTA Firmware Update ── */
+  .ota-card { display:flex; flex-direction:column; gap:14px; }
+  .ota-notice { display:flex; gap:12px; align-items:flex-start; padding:10px 12px; background:color-mix(in srgb, var(--warn) 8%, var(--bg)); border-left:3px solid var(--warn); }
+  .ota-notice-icon { font-size:16px; color:var(--warn); flex-shrink:0; line-height:1.4; }
+  .ota-notice-title { font-family:var(--sans); font-size:11px; font-weight:700; color:var(--warn); letter-spacing:0.08em; text-transform:uppercase; margin-bottom:4px; }
+  .ota-notice-body { font-family:var(--mono); font-size:10px; color:var(--label); line-height:1.6; }
+  .ota-steps { font-family:var(--mono); font-size:10px; color:var(--label); line-height:1.9; margin:0; padding-left:18px; }
+  .ota-steps code { color:var(--text); }
+  .ota-steps strong { color:var(--text); }
+  .ota-steps em { color:var(--accent); font-style:normal; }
+  .ota-btn-row { display:grid; gap:8px; }
+  .ota-status-row { min-height:14px; }
+  .ota-status { font-family:var(--mono); font-size:10px; color:var(--label); }
+  .ota-status.ota-ok  { color:var(--ok); }
+  .ota-status.ota-err { color:var(--accent2); }
+  .cmd-btn.ota-trigger::before { background:var(--accent); }
+  .cmd-btn.ota-trigger:hover   { border-color:var(--accent); }