Implement BLE OTA

.gitignore

@@ -5,4 +5,5 @@
 *.claude
 *.vscode
 web/version.js
-samples/
+samples/
+firmware_dfu.zip

model/pointer.FCMacro

@@ -1,290 +1,430 @@
-# IMU Pointer Enclosure
+"""
+IMU Pointer Enclosure  —  v6
+============================
+Fixes from v5 (diagnosed from rendered images):
+
+  1. BOTTOM HOLE:
+     v5 built the bottom shell from a full-height box (0→H) then trimmed
+     at SPLIT_Z. The taper wedge interacted badly with the split cut near
+     X=0 leaving a hole in the floor. Fix: build bottom outer solid only
+     to SPLIT_Z height — no trimming step needed, no interaction.
+
+  2. TOP SHELL WALLS PROTRUDING BELOW SPLIT:
+     v5 top_outer started at SPLIT_Z but the cavity inside started at
+     SPLIT_Z + WALL, leaving WALL=3.5mm of solid wall below the groove —
+     visually protruding past the bottom shell. Fix: the top shell outer
+     solid starts at SPLIT_Z. The groove is cut starting exactly at SPLIT_Z
+     so there is zero protrusion below the split line.
+
+  3. BUTTON CAP NOT FLUSH / SITTING PROUD:
+     Aperture cylinder had arithmetic-derived Z that could miss the top wall
+     faces after filleting. Fix: aperture runs from Z=SPLIT_Z (well inside
+     the cavity) all the way to Z=H+2 — brute-force punch, impossible to miss.
+
+  4. CAP RIM SITS UNDER OUTER FACE (not above it):
+     Cap is placed so shaft top = H (flush). Rim hangs BELOW the top face
+     inside the cavity — correct retention geometry. The cap shaft top is
+     exactly flush with H. No part of the cap protrudes above H.
+
+Split joint design:
+  - Bottom shell has a TONGUE that projects UP from SPLIT_Z.
+    The tongue is a thin rectangular frame (inner perimeter of the walls).
+  - Top shell has a matching GROOVE cut into the inside of its lower edge,
+    starting exactly at SPLIT_Z (the bottom face of the top shell).
+  - Two flex notches cut through the tongue on the long sides allow snap fit.
+"""
 
 import FreeCAD as App
 import FreeCADGui as Gui
 import Part
+import math
 from FreeCAD import Base
 
-doc = App.newDocument("pointer")
+doc = App.newDocument("pointer_v7")
 
-# Global dimensions
-L = 115.0
-W = 36.0
-H = 20.0
-WALL = 3.5
-CR = 3.0
-TOL = 0.25
+# ─────────────────────────────────────────────────────────────────────────────
+#  DIMENSIONS
+# ─────────────────────────────────────────────────────────────────────────────
+L    = 115.0   # length (X): front=0, back=L
+W    = 36.0    # width  (Y)
+H    = 22.0    # height (Z): bottom=0, top=H
+WALL = 4.5     # wall thickness (+1 mm vs v6 — closes taper floor gap)
+CR   = 5.0     # corner fillet radius (vertical edges)
+TOL  = 0.25    # fit tolerance
 
-# Rail and lid
-RAIL_H = 4.5
-RAIL_D = 2.0
-LIP_H = 2.0
-LIP_OVER = 1.5
-LIP_EMBED = 0.2
+# Taper: front of bottom shell is TAPER_RISE mm shorter than back.
+# Applied only to the BOTTOM shell (it's where the ergonomic taper lives).
+TAPER_RISE = 0.0    # no taper — removed per user request
+TAPER_LEN  = 100.0  # unused but kept to avoid NameError
 
-LID_H = RAIL_H - LIP_H - TOL - 0.55
+# Split plane
+USBC_W  = 11.0
+USBC_H  =  7.0
+USBC_Z  =  5.0
+SPLIT_Z = USBC_Z + USBC_H + 2.5   # = 14.5 mm
 
-# Board dimensions
-PCB_T = 1.0
-BRD_L = 21.0
-BRD_W = 17.5
-BRD_X = WALL
-BRD_Y = (W - BRD_W) / 2
+# Tongue/groove clip joint
+TONGUE_H = 2.5   # how far tongue projects above SPLIT_Z
+TONGUE_T = 1.2   # tongue wall thickness
+GROOVE_H = TONGUE_H + TOL
+GROOVE_T = TONGUE_T + TOL
 
+# Flex notch through tongue (for snap release)
+NOTCH_W  = 8.0
+NOTCH_H  = TONGUE_H + 0.5
+
+# ─────────────────────────────────────────────────────────────────────────────
+#  IMU BOARD
+# ─────────────────────────────────────────────────────────────────────────────
+PCB_T      = 1.0
+BRD_L      = 21.0
+BRD_W      = 17.5
+BRD_X      = WALL
+BRD_Y      = (W - BRD_W) / 2.0
 PLATFORM_H = 0.5
-BRD_Z = WALL + PLATFORM_H
+BRD_Z      = WALL + PLATFORM_H
+ARM_LEN    = 5.0
+ARM_THICK  = 1.6
+ARM_H      = BRD_Z + PCB_T + 0.8
+CLIP_TOL   = 0.35
 
-# Clip arms
-ARM_LEN = 5.0
-ARM_THICK = 1.6
-ARM_H = BRD_Z + PCB_T + 0.8
-CLIP_TOL = 0.35
+# ─────────────────────────────────────────────────────────────────────────────
+#  BATTERY BAY
+# ─────────────────────────────────────────────────────────────────────────────
+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) / 2.0
+BAT_CLIP_Y =  8.0
 
-# USB-C cutout
-USBC_W = 11.0
-USBC_H = 7.0
-USBC_Z = 4.5
+# ─────────────────────────────────────────────────────────────────────────────
+#  BUTTON
+# ─────────────────────────────────────────────────────────────────────────────
+BTN_X       = 28.0
+BTN_CY      = W / 2.0
+BTN_HOLE_R  = 8.0
+CAP_SHAFT_R = BTN_HOLE_R - 0.4   # 0.4 mm radial clearance in hole
+CAP_SHAFT_H = WALL                # shaft fills top wall → top face flush
+CAP_RIM_R   = BTN_HOLE_R + 2.0   # 2 mm wider than hole → retention
+CAP_RIM_H   = 1.5
+NUBBIN_R    = 1.8
+NUBBIN_H    = 2.0
 
-# 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
-BAT_CLIP_Y = 8.0
+# Switch geometry (adjust to match your Omron)
+SWITCH_BODY_H = 5.0
+STEM_H        = 2.5
+GAP           = 0.5
 
-# Circular notch
-NOTCH_R     = (USBC_W + TOL) / 2
-NOTCH_DEPTH = WALL + 2.0
+# PCB position derived top-down
+PCB_TOP_Z = H - WALL - CAP_RIM_H - NUBBIN_H - GAP - SWITCH_BODY_H - STEM_H
+PCB_BOT_Z = PCB_TOP_Z - PCB_T
+# Clamp: must be inside the top shell cavity
+floor_top_shell = SPLIT_Z + WALL
+if PCB_BOT_Z < floor_top_shell + 0.5:
+    PCB_BOT_Z = floor_top_shell + 0.5
+    PCB_TOP_Z = PCB_BOT_Z + PCB_T
 
+POST_H   = PCB_BOT_Z - floor_top_shell
+POST_OD  = 4.0;  POST_R  = POST_OD / 2.0
+POST_ID  = 1.9;  POST_IR = POST_ID / 2.0
+POST_SEP = 3.0
 
-# Circular notch helper
-def circular_notch(face_x, cy, cz, r, depth):
-    circle = Part.makeCircle(r, Base.Vector(face_x, cy, cz), Base.Vector(1, 0, 0))
-    face = Part.Face(Part.Wire(circle))
-    return face.extrude(Base.Vector(-depth, 0, 0))
+BPCB_L     = 16.0
+BPCB_W     = 16.0
+SHELF_WALL = 2.0
 
+# ─────────────────────────────────────────────────────────────────────────────
+#  HELPERS
+# ─────────────────────────────────────────────────────────────────────────────
 
-# 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
-
-
-# Simple box helper
-def box(lx, ly, lz, ox=0, oy=0, oz=0):
+def box(lx, ly, lz, ox=0.0, oy=0.0, oz=0.0):
     return Part.makeBox(lx, ly, lz, Base.Vector(ox, oy, oz))
 
+def cyl(r, h, cx=0.0, cy=0.0, cz=0.0):
+    return Part.makeCylinder(r, h, Base.Vector(cx, cy, cz))
 
-# Rounded slot helper
-def rounded_slot(depth, w, h, ox, oy, oz, r=None):
-    if r is None:
-        r = h / 2.0
+def rounded_slot(depth, sw, sh, ox, oy, oz):
+    """Stadium slot extruded in +X."""
+    r  = min(sh / 2.0, sw / 2.0)
+    cy = oy + sw / 2.0
+    cz = oz + sh / 2.0
+    hw = max(sw / 2.0 - r, 0.0)
+    if hw < 1e-6:
+        circ = Part.makeCircle(r, Base.Vector(ox, cy, cz), Base.Vector(1, 0, 0))
+        return Part.Face(Part.Wire(circ)).extrude(Base.Vector(depth, 0, 0))
+    l_s = Base.Vector(ox, cy - hw, cz - r)
+    l_m = Base.Vector(ox, cy - hw - r, cz)
+    l_e = Base.Vector(ox, cy - hw, cz + r)
+    r_s = Base.Vector(ox, cy + hw, cz + r)
+    r_m = Base.Vector(ox, cy + hw + r, cz)
+    r_e = Base.Vector(ox, cy + hw, cz - r)
+    wire = Part.Wire([Part.Arc(l_s, l_m, l_e).toShape(),
+                      Part.makeLine(l_e, r_s),
+                      Part.Arc(r_s, r_m, r_e).toShape(),
+                      Part.makeLine(r_e, l_s)])
+    return Part.Face(wire).extrude(Base.Vector(depth, 0, 0))
 
-    r = min(r, h / 2.0, w / 2.0)
-
-    import math
-
-    cy = oy + w / 2.0
-    cz = oz + h / 2.0
-    hw = w / 2.0 - r
-
-    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)
-        )
-
-    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()
-
-    line_top = Part.makeLine(
-        l_end,
-        pt(ox, cy + hw, cz, 90, r)
-    )
-
-    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()
-
-    line_bot = Part.makeLine(r_end, l_start)
-
-    wire = Part.Wire([arc_left, line_top, arc_right, line_bot])
-    face = Part.Face(wire)
-
-    return face.extrude(Base.Vector(depth, 0, 0))
-
-
-# Board clip helper
-def make_clip(corner_x, corner_y, inward_x, inward_y):
+def fillet_vert(solid, r, min_len=4.0):
+    """Fillet edges that are primarily vertical (parallel to Z)."""
+    try:
+        edges = [e for e in solid.Edges
+                 if len(e.Vertexes) == 2
+                 and abs(e.Vertexes[0].X - e.Vertexes[1].X) < 1e-3
+                 and abs(e.Vertexes[0].Y - e.Vertexes[1].Y) < 1e-3
+                 and e.Length >= min_len]
+        if edges:
+            return solid.makeFillet(r, edges)
+    except Exception as e:
+        print(f"  fillet_vert skipped: {e}")
+    return solid
 
+def make_clip(cx, cy, ix, iy):
     plat_w = ARM_THICK + CLIP_TOL
+    plat_x = cx if ix > 0 else cx - plat_w
+    plat_y = cy if iy > 0 else cy - plat_w
+    plat   = box(plat_w, plat_w, PLATFORM_H + PCB_T, plat_x, plat_y, WALL)
+    ax_ox  = cx if ix > 0 else cx - ARM_LEN
+    ax_oy  = cy - ARM_THICK - CLIP_TOL if iy > 0 else cy + CLIP_TOL
+    arm_x  = box(ARM_LEN, ARM_THICK, ARM_H, ax_ox, ax_oy, WALL)
+    ay_oy  = cy if iy > 0 else cy - ARM_LEN
+    ay_ox  = cx - ARM_THICK - CLIP_TOL if ix > 0 else cx + CLIP_TOL
+    arm_y  = box(ARM_THICK, ARM_LEN, ARM_H, ay_ox, ay_oy, WALL)
+    cb_w   = ARM_THICK + CLIP_TOL
+    cb_ox  = cx - cb_w if ix > 0 else cx
+    cb_oy  = cy - cb_w if iy > 0 else cy
+    cb     = box(cb_w, cb_w, ARM_H, cb_ox, cb_oy, WALL)
+    return plat.fuse(arm_x.fuse(arm_y).fuse(cb))
 
-    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
+# ═════════════════════════════════════════════════════════════════════════════
+#  BOTTOM SHELL  (Z = 0 → SPLIT_Z, open on top)
+# ═════════════════════════════════════════════════════════════════════════════
 
-    platform = box(
-        plat_w, plat_w,
-        PLATFORM_H + PCB_T,
-        plat_x, plat_y, WALL
-    )
+# 1. Outer solid — built ONLY to SPLIT_Z height
+bot_outer = box(L, W, SPLIT_Z)
+bot_outer = fillet_vert(bot_outer, CR, min_len=SPLIT_Z * 0.4)
 
-    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)
+# Fillet the long horizontal edges the user holds.
+# These are the 4 edges running in X at Z≈0 and Z≈SPLIT_Z, on both long sides.
+# Same fillet applied to equivalent edges on the top shell later.
+EDGE_FILLET = 2.5   # mm — soft and comfortable, visible but not decorative
+try:
+    h_edges = []
+    for e in bot_outer.Edges:
+        if len(e.Vertexes) != 2:
+            continue
+        v0, v1 = e.Vertexes[0], e.Vertexes[1]
+        dx = abs(v0.X - v1.X)
+        dz = abs(v0.Z - v1.Z)
+        dy = abs(v0.Y - v1.Y)
+        # Long edge in X, horizontal, on a long side face —
+        # but ONLY at Z≈0 (bottom face). Exclude Z≈SPLIT_Z (the join edge).
+        z_mid = (v0.Z + v1.Z) / 2.0
+        if dx > L * 0.5 and dz < 0.5 and dy < 0.5 and z_mid < 1.0:
+            h_edges.append(e)
+    if h_edges:
+        bot_outer = bot_outer.makeFillet(EDGE_FILLET, h_edges)
+        print(f"Bottom shell: filleted {len(h_edges)} horizontal edge(s) R={EDGE_FILLET}")
+    else:
+        print("Bottom shell: no horizontal edges found — skipped")
+except Exception as exc:
+    print(f"Bottom shell horizontal fillet skipped: {exc}")
 
-    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)
+# No taper wedge — removed per user request
 
-    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
+# 3. Inner cavity — floor at WALL, ceiling at SPLIT_Z (open top, no ceiling)
+bot_cav_lx = L - WALL * 2
+bot_cav_ly = W - WALL * 2
+bot_cav_lz = SPLIT_Z - WALL   # floor(WALL) → SPLIT_Z
+bot_inner  = box(bot_cav_lx, bot_cav_ly, bot_cav_lz, WALL, WALL, WALL)
+bot_shell  = bot_outer.cut(bot_inner)
 
-    corner_block = box(
-        corner_block_w, corner_block_w, ARM_H,
-        cb_ox, cb_oy, WALL
-    )
+# 4. Tongue (projects UP from SPLIT_Z, inner perimeter frame)
+#    Outer edge of tongue = inner face of outer wall = WALL from outside
+#    Inner edge of tongue = WALL + TONGUE_T from outside
+t_slab = box(bot_cav_lx,          bot_cav_ly,          TONGUE_H,
+             WALL,                 WALL,                 SPLIT_Z)
+t_cut  = box(bot_cav_lx - TONGUE_T*2, bot_cav_ly - TONGUE_T*2, TONGUE_H + 1,
+             WALL + TONGUE_T,     WALL + TONGUE_T,     SPLIT_Z - 0.5)
+tongue = t_slab.cut(t_cut)
 
-    return platform.fuse(arm_x.fuse(arm_y).fuse(corner_block))
+# Flex notches on the two long sides (parallel to X)
+nx0 = L / 2.0 - NOTCH_W / 2.0
+for ny_start in [WALL, W - WALL - TONGUE_T]:
+    tongue = tongue.cut(
+        box(NOTCH_W, TONGUE_T + 0.5, NOTCH_H,
+            nx0, ny_start - 0.1, SPLIT_Z - 0.1))
+bot_shell = bot_shell.fuse(tongue)
 
-
-# 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),
+# 5. IMU clips
+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_clip(cx, cy, ix, iy))
 
-for cx, cy, ix, iy in clip_corners:
-    base = base.fuse(make_clip(cx, cy, ix, iy))
+# 6. USB-C slot — starts at X = -WALL*3 so it punches through the rounded
+#    front face cleanly regardless of fillet radius
+bot_shell = bot_shell.cut(
+    rounded_slot(WALL * 6, USBC_W, USBC_H,
+                 -WALL * 3,
+                 W / 2.0 - USBC_W / 2.0,
+                 USBC_Z))
 
-# USB-C opening
-base = base.cut(
-    rounded_slot(
-        WALL * 3,
-        USBC_W,
-        USBC_H,
-        -WALL,
-        W / 2 - USBC_W / 2,
-        USBC_Z
-    )
-)
+# 7. Battery bay
+bot_shell = bot_shell.cut(box(BAT_L, BAT_W, 3.0, BAT_X, BAT_Y, WALL))
+cy0 = 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,   cy0, WALL))
+bot_shell = bot_shell.fuse(box(2.0, BAT_CLIP_Y, BAT_H * 0.55, BAT_X + BAT_L, cy0, WALL))
 
-# Battery recess
-base = base.cut(
-    box(BAT_L, BAT_W, 3.0,
-        BAT_X, BAT_Y, WALL)
-)
+# ═════════════════════════════════════════════════════════════════════════════
+#  TOP SHELL  (Z = SPLIT_Z → H, open on bottom, closed ceiling at H)
+# ═════════════════════════════════════════════════════════════════════════════
+top_h = H - SPLIT_Z   # = 7.5 mm
 
-clip_y_start = BAT_Y + BAT_W / 2 - BAT_CLIP_Y / 2
+# 1. Outer solid spans SPLIT_Z → H
+top_outer = box(L, W, top_h, 0, 0, SPLIT_Z)
+top_outer = fillet_vert(top_outer, CR, min_len=top_h * 0.4)
 
-base = base.fuse(
-    box(2.0, BAT_CLIP_Y, BAT_H * 0.55,
-        BAT_X - 2.0, clip_y_start, WALL)
-)
+# Fillet the long horizontal edges of the top shell —
+# the top edges (Z≈H) are the ones selected in blue in the user's screenshot.
+try:
+    th_edges = []
+    for e in top_outer.Edges:
+        if len(e.Vertexes) != 2:
+            continue
+        v0, v1 = e.Vertexes[0], e.Vertexes[1]
+        dx = abs(v0.X - v1.X)
+        dz = abs(v0.Z - v1.Z)
+        dy = abs(v0.Y - v1.Y)
+        # Long edge in X, horizontal, on a long side face —
+        # ONLY at Z≈H (top face). Exclude Z≈SPLIT_Z (the join edge).
+        z_mid = (v0.Z + v1.Z) / 2.0
+        if dx > L * 0.5 and dz < 0.5 and dy < 0.5 and z_mid > H - 1.0:
+            th_edges.append(e)
+    if th_edges:
+        top_outer = top_outer.makeFillet(EDGE_FILLET, th_edges)
+        print(f"Top shell: filleted {len(th_edges)} horizontal edge(s) R={EDGE_FILLET}")
+    else:
+        print("Top shell: no horizontal edges found — skipped")
+except Exception as exc:
+    print(f"Top shell horizontal fillet skipped: {exc}")
 
-base = base.fuse(
-    box(2.0, BAT_CLIP_Y, BAT_H * 0.55,
-        BAT_X + BAT_L, clip_y_start, WALL)
-)
+# 2. Inner cavity: side walls WALL thick, CEILING at H-WALL (WALL-thick roof),
+#    FLOOR open (starts at SPLIT_Z — nothing blocks the bottom opening).
+#    Cavity box: X from WALL→L-WALL, Y from WALL→W-WALL, Z from SPLIT_Z→H-WALL
+top_cav_lx = L - WALL * 2
+top_cav_ly = W - WALL * 2
+top_cav_lz = top_h - WALL     # = 7.5 - 3.5 = 4.0 mm interior height
+top_inner  = box(top_cav_lx, top_cav_ly, top_cav_lz,
+                 WALL, WALL, SPLIT_Z)        # starts exactly at SPLIT_Z
+top_shell  = top_outer.cut(top_inner)
 
-# Circular notch in back wall - centred on base
-notch_cz = rail_z + LID_H
-base = base.cut(circular_notch(L, W / 2, notch_cz, NOTCH_R, NOTCH_DEPTH))
+# 3. Groove at the bottom of the top shell, starting at SPLIT_Z
+#    The groove is a frame-shaped recess cut into the inner face of the walls.
+#    It goes from Z=SPLIT_Z up to Z=SPLIT_Z+GROOVE_H.
+#    Width = GROOVE_T (slightly wider than tongue).
+g_slab = box(top_cav_lx, top_cav_ly, GROOVE_H,
+             WALL, WALL, SPLIT_Z)
+g_cut  = box(top_cav_lx - GROOVE_T*2, top_cav_ly - GROOVE_T*2, GROOVE_H + 1,
+             WALL + GROOVE_T, WALL + GROOVE_T, SPLIT_Z - 0.5)
+groove = g_slab.cut(g_cut)
+top_shell = top_shell.cut(groove)
 
-# Lid
-TAB_W = RAIL_D - TOL + 0.5
-LID_L = L - WALL * 2 - TOL
-LID_EXTRA_TOL = 0.5
+# 4. Button aperture — brute-force: run cylinder from Z=SPLIT_Z to Z=H+2.
+#    It will punch through the ceiling regardless of any topology.
+top_shell = top_shell.cut(
+    cyl(BTN_HOLE_R, H - SPLIT_Z + 2, BTN_X, BTN_CY, SPLIT_Z))
 
-LID_W = (
-    W - WALL * 2
-    - (TOL + LID_EXTRA_TOL) * 2
-    + TAB_W * 2
-)
+# 5. Button PCB shelf frame
+shelf_ox   = BTN_X  - BPCB_L / 2.0
+shelf_oy   = BTN_CY - BPCB_W / 2.0
+shelf_h    = 1.5
+shelf_slab = box(BPCB_L + SHELF_WALL*2, BPCB_W + SHELF_WALL*2, shelf_h,
+                 shelf_ox - SHELF_WALL,  shelf_oy - SHELF_WALL,
+                 PCB_BOT_Z - shelf_h)
+shelf_hole = box(BPCB_L, BPCB_W, shelf_h + 2.0,
+                 shelf_ox, shelf_oy, PCB_BOT_Z - shelf_h - 1.0)
+shelf = shelf_slab.cut(shelf_hole)
+if floor_top_shell < PCB_BOT_Z < H - WALL:
+    top_shell = top_shell.fuse(shelf)
 
-lid_y0 = WALL + TOL + LID_EXTRA_TOL - TAB_W
-lid = box(LID_L, LID_W, LID_H, 0, lid_y0, 0)
+# 6. Screw posts on top-shell floor
+if POST_H > 0.5:
+    for py in [BTN_CY - POST_SEP/2.0, BTN_CY + POST_SEP/2.0]:
+        p  = cyl(POST_R,  POST_H,        BTN_X, py, floor_top_shell)
+        ph = cyl(POST_IR, POST_H + 1.0,  BTN_X, py, floor_top_shell)
+        top_shell = top_shell.fuse(p)
+        top_shell = top_shell.cut(ph)
 
-lid.translate(Base.Vector(WALL + TOL, 0, rail_z))
+# ═════════════════════════════════════════════════════════════════════════════
+#  BUTTON CAP  (separate printed part)
+#
+#  Geometry at origin:
+#    Shaft:   Z = 0 (bottom/inner) → Z = CAP_SHAFT_H = WALL   (top/flush)
+#    Rim:     Z = -CAP_RIM_H → Z = 0   (hangs inside cavity)
+#    Nubbin:  Z = -CAP_RIM_H-NUBBIN_H → Z = -CAP_RIM_H
+#
+#  Placed so shaft top = H  → flush with top face.
+#  Rim is entirely inside the cavity. No part protrudes above H.
+# ═════════════════════════════════════════════════════════════════════════════
+cap_shaft = cyl(CAP_SHAFT_R, CAP_SHAFT_H)
+cap_rim   = cyl(CAP_RIM_R,   CAP_RIM_H,   0, 0, -CAP_RIM_H)
+cap_nub   = cyl(NUBBIN_R,    NUBBIN_H,    0, 0, -CAP_RIM_H - NUBBIN_H)
+cap_raw   = cap_shaft.fuse(cap_rim).fuse(cap_nub)
+# No fillet on cap top rim — cap sits flush inside aperture so a fillet
+# would create a visible chamfer ring against the hole edge.
+cap_placed = cap_raw.copy()
+cap_placed.translate(Base.Vector(BTN_X, BTN_CY, H - CAP_SHAFT_H))
 
-# Final objects
-base_obj = doc.addObject("Part::Feature", "Pointer_Base")
-base_obj.Shape = base
-base_obj.ViewObject.ShapeColor = (0.12, 0.12, 0.14)
+# ═════════════════════════════════════════════════════════════════════════════
+#  REGISTER OBJECTS
+# ═════════════════════════════════════════════════════════════════════════════
+bot_obj = doc.addObject("Part::Feature", "Shell_Bottom")
+bot_obj.Shape = bot_shell
+bot_obj.ViewObject.ShapeColor   = (0.12, 0.12, 0.14)
+bot_obj.ViewObject.Transparency = 0
 
-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
+top_obj = doc.addObject("Part::Feature", "Shell_Top")
+top_obj.Shape = top_shell
+top_obj.ViewObject.ShapeColor   = (0.20, 0.20, 0.26)
+top_obj.ViewObject.Transparency = 0
+
+cap_obj = doc.addObject("Part::Feature", "Button_Cap")
+cap_obj.Shape = cap_placed
+cap_obj.ViewObject.ShapeColor   = (0.80, 0.80, 0.86)
+cap_obj.ViewObject.Transparency = 0
 
 doc.recompute()
 Gui.activeDocument().activeView().viewIsometric()
-Gui.SendMsgToActiveView("ViewFit")
+Gui.SendMsgToActiveView("ViewFit")
+
+# ═════════════════════════════════════════════════════════════════════════════
+#  SUMMARY
+# ═════════════════════════════════════════════════════════════════════════════
+print("=" * 62)
+print("IMU Pointer v7")
+print("=" * 62)
+print(f"Body:          {L:.0f} × {W:.0f} mm")
+print(f"Height:        {H:.0f} mm uniform (no taper)")
+print(f"Wall:          {WALL:.1f} mm    CR = {CR:.1f} mm    Edge fillet = {EDGE_FILLET:.1f} mm")
+print(f"Split Z:       {SPLIT_Z:.1f} mm  "
+      f"(USB-C top = {USBC_Z + USBC_H:.1f} mm)")
+print(f"Top shell interior height: {top_cav_lz:.1f} mm  (Z {SPLIT_Z:.1f} → {H - WALL:.1f})")
+print()
+print(f"Tongue H/T:    {TONGUE_H:.1f} / {TONGUE_T:.1f} mm")
+print(f"Groove H/T:    {GROOVE_H:.2f} / {GROOVE_T:.2f} mm")
+print()
+print(f"Button hole:   ⌀{BTN_HOLE_R*2:.0f} mm  X={BTN_X}  Y={BTN_CY:.0f}")
+print(f"Cap shaft:     ⌀{CAP_SHAFT_R*2:.1f} mm × {CAP_SHAFT_H:.1f} mm  (flush, Z {H-WALL:.1f}→{H:.1f})")
+print(f"Cap rim:       ⌀{CAP_RIM_R*2:.0f} mm × {CAP_RIM_H:.1f} mm  (retention, below top face)")
+print()
+print(f"PCB top Z:     {PCB_TOP_Z:.2f} mm  (above split floor {floor_top_shell:.1f} mm)")
+print(f"PCB bot Z:     {PCB_BOT_Z:.2f} mm")
+print(f"Post H:        {POST_H:.2f} mm  ⌀{POST_OD:.0f}/{POST_ID:.1f} mm  sep={POST_SEP:.0f} mm c-to-c")
+print()
+print(f"Switch stack:  body={SWITCH_BODY_H} + stem={STEM_H} + gap={GAP} mm")
+print("  Adjust SWITCH_BODY_H / STEM_H if your Omron differs.")
+print("=" * 62)

platformio.ini

@@ -25,8 +25,10 @@ upload_speed    = 115200
 ; Uncomment and set the correct port if auto-detect fails:
 ; upload_port   = COM3
 
-;  Build scripts 
-extra_scripts = pre:scripts/git_hash.py
+;  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 =

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

source/ble_config.cpp

@@ -77,9 +77,6 @@ void pushConfigBlob() {
   b.tapFreezeEnabled = cfg.tapFreezeEnabled;
   b.jerkThreshold    = cfg.jerkThreshold;
   b.featureFlags     = cfg.featureFlags;
-  b.btnLeftPin       = cfg.btnLeftPin;
-  b.btnRightPin      = cfg.btnRightPin;
-  b.btnMiddlePin     = cfg.btnMiddlePin;
   cfgBlob.write((uint8_t*)&b, sizeof(b));
 }
 #endif
@@ -125,13 +122,6 @@ void onConfigBlobWrite(uint16_t h, BLECharacteristic* c, uint8_t* d, uint16_t l)
   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);
-  // btnXPin: accept BTN_PIN_NONE (0xFF) or a valid Arduino pin number (0-10 = D0-D10)
-  cfg.btnLeftPin   = (b->btnLeftPin   <= 10 || b->btnLeftPin   == BTN_PIN_NONE) ? b->btnLeftPin   : BTN_PIN_NONE;
-  cfg.btnRightPin  = (b->btnRightPin  <= 10 || b->btnRightPin  == BTN_PIN_NONE) ? b->btnRightPin  : BTN_PIN_NONE;
-  cfg.btnMiddlePin = (b->btnMiddlePin <= 10 || b->btnMiddlePin == BTN_PIN_NONE) ? b->btnMiddlePin : BTN_PIN_NONE;
-  #ifdef FEATURE_PHYSICAL_BUTTONS
-    setupPhysicalButtons();   // reconfigure pins immediately (no restart needed)
-  #endif
   saveConfig();
   Serial.print("[CFG] Written - sens="); Serial.print(cfg.sensitivity,0);
   Serial.print(" dz="); Serial.print(cfg.deadZone,3);
@@ -143,6 +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
@@ -163,7 +156,7 @@ 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);

source/buttons.cpp

@@ -13,19 +13,19 @@ void setupPhysicalButtons() {
   if (physBtnMask && Bluefruit.connected()) { blehid.mouseButtonRelease(); }
   physBtnMask = 0;
 
-  if (cfg.btnLeftPin   != BTN_PIN_NONE) pinMode(cfg.btnLeftPin,   INPUT_PULLUP);
-  if (cfg.btnRightPin  != BTN_PIN_NONE) pinMode(cfg.btnRightPin,  INPUT_PULLUP);
-  if (cfg.btnMiddlePin != BTN_PIN_NONE) pinMode(cfg.btnMiddlePin, INPUT_PULLUP);
+  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 = (cfg.btnLeftPin != BTN_PIN_NONE) || (cfg.btnRightPin != BTN_PIN_NONE)
-          || (cfg.btnMiddlePin != BTN_PIN_NONE);
+  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=");
-    cfg.btnLeftPin   == BTN_PIN_NONE ? Serial.print("--") : Serial.print(cfg.btnLeftPin);
+    BTN_LEFT_PIN   == BTN_PIN_NONE ? Serial.print("--") : Serial.print(BTN_LEFT_PIN);
     Serial.print(" R=");
-    cfg.btnRightPin  == BTN_PIN_NONE ? Serial.print("--") : Serial.print(cfg.btnRightPin);
+    BTN_RIGHT_PIN  == BTN_PIN_NONE ? Serial.print("--") : Serial.print(BTN_RIGHT_PIN);
     Serial.print(" M=");
-    cfg.btnMiddlePin == BTN_PIN_NONE ? Serial.print("--") : Serial.print(cfg.btnMiddlePin);
+    BTN_MIDDLE_PIN == BTN_PIN_NONE ? Serial.print("--") : Serial.print(BTN_MIDDLE_PIN);
     Serial.println();
   }
 }
@@ -37,9 +37,9 @@ void processPhysicalButtons() {
   if (!Bluefruit.connected()) return;
 
   uint8_t newMask = 0;
-  if (cfg.btnLeftPin   != BTN_PIN_NONE && digitalRead(cfg.btnLeftPin)   == LOW) newMask |= MOUSE_BUTTON_LEFT;
-  if (cfg.btnRightPin  != BTN_PIN_NONE && digitalRead(cfg.btnRightPin)  == LOW) newMask |= MOUSE_BUTTON_RIGHT;
-  if (cfg.btnMiddlePin != BTN_PIN_NONE && digitalRead(cfg.btnMiddlePin) == LOW) newMask |= MOUSE_BUTTON_MIDDLE;
+  if (BTN_LEFT_PIN   != BTN_PIN_NONE && digitalRead(BTN_LEFT_PIN)   == LOW) newMask |= MOUSE_BUTTON_LEFT;
+  if (BTN_RIGHT_PIN  != BTN_PIN_NONE && digitalRead(BTN_RIGHT_PIN)  == LOW) newMask |= MOUSE_BUTTON_RIGHT;
+  if (BTN_MIDDLE_PIN != BTN_PIN_NONE && digitalRead(BTN_MIDDLE_PIN) == LOW) newMask |= MOUSE_BUTTON_MIDDLE;
 
   if (newMask != physBtnMask) {
     physBtnMask = newMask;

source/config.h

@@ -11,6 +11,7 @@
 #define FEATURE_BATTERY_MONITOR
 #define FEATURE_BOOT_LOOP_DETECT
 #define FEATURE_PHYSICAL_BUTTONS
+#define FEATURE_OTA
 
 // Debug 
 // #define DEBUG
@@ -56,8 +57,12 @@
 #define CONFIG_FILENAME  "/imu_mouse_cfg.bin"
 #define CONFIG_MAGIC     0xDEAD123EUL
 
-// Physical button sentinel 
-#define BTN_PIN_NONE  0xFF   // Stored in btn*Pin when that button is disabled
+// 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   BTN_PIN_NONE   // e.g. 0 for D0
+#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
@@ -98,9 +103,6 @@ struct Config {
   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
-  uint8_t    btnLeftPin;       // BTN_PIN_NONE or Arduino pin number (0-10 = D0-D10)
-  uint8_t    btnRightPin;
-  uint8_t    btnMiddlePin;
 };
 extern Config cfg;
 extern const Config CFG_DEFAULTS;
@@ -120,11 +122,8 @@ struct __attribute__((packed)) ConfigBlob {
   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
-  uint8_t btnLeftPin;        // [25]  BTN_PIN_NONE or Arduino pin (0-10 = D0-D10)
-  uint8_t btnRightPin;       // [26]
-  uint8_t btnMiddlePin;      // [27]
 };
-static_assert(sizeof(ConfigBlob) == 28, "ConfigBlob must be 28 bytes");
+static_assert(sizeof(ConfigBlob) == 25, "ConfigBlob must be 25 bytes");
 
 // TelemetryPacket (24 bytes) 
 #ifdef FEATURE_TELEMETRY
@@ -207,6 +206,9 @@ 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/main.cpp

@@ -47,8 +47,7 @@ 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,
-  /*jerkThreshold=*/2000.0f, /*tapFreezeEnabled=*/1, /*featureFlags=*/FLAG_ALL_DEFAULT,
-  /*btnLeftPin=*/BTN_PIN_NONE, /*btnRightPin=*/BTN_PIN_NONE, /*btnMiddlePin=*/BTN_PIN_NONE
+  /*jerkThreshold=*/2000.0f, /*tapFreezeEnabled=*/1, /*featureFlags=*/FLAG_ALL_DEFAULT
 };
 
 // Telemetry definition 
@@ -59,6 +58,8 @@ TelemetryPacket telem = {};
 // Tuning constants 
 const float ALPHA              = 0.96f;
 const int   LOOP_RATE_MS       = 10;
+const float SMOOTH_LOW_RPS     = 0.15f;  // below this → heavy EMA smoothing (~8°/s)
+const float SMOOTH_HIGH_RPS    = 0.50f;  // above this → no smoothing (~29°/s)
 const int   BIAS_SAMPLES       = 200;
 const int   IDLE_FRAMES        = 150;
 const unsigned long BATT_REPORT_MS       = 20000;
@@ -116,6 +117,9 @@ float cachedTempC = 25.0f;
 uint32_t loopStalls = 0;          // loop iterations where dt > 20ms (behind schedule)
 bool pendingCal   = false;
 bool pendingReset = false;
+#ifdef FEATURE_OTA
+  bool pendingOTA = false;
+#endif
 
 // Jerk-based shock detection - freeze cursor during tap impacts, doesn't work well yet!
 unsigned long shockFreezeUntil = 0;
@@ -298,10 +302,28 @@ void loop() {
     char cmd = Serial.read();
     if (cmd == 'c') { Serial.println("[SERIAL] Calibrate"); pendingCal   = true; }
     if (cmd == 'r') { Serial.println("[SERIAL] Reset");     pendingReset = true; }
+    #ifdef FEATURE_OTA
+      if (cmd == 'o') { Serial.println("[SERIAL] OTA DFU"); pendingOTA = true; }
+    #endif
   }
 
   if (pendingCal)   { pendingCal = false; calibrateGyroBias(); prevAx = imu.readFloatAccelX(); prevAy = imu.readFloatAccelY(); prevAz = imu.readFloatAccelZ(); }
   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) {
@@ -425,11 +447,15 @@ void loop() {
   int8_t  moveX = 0, moveY = 0;
   uint8_t flags = 0;
 
+  static float smoothX = 0.0f, smoothY = 0.0f;
+
   if (shocked) {
     // Shock freeze - discard accumulated sub-pixel motion and suppress output
+    smoothX = smoothY = 0.0f;
     accumX = accumY = 0.0f;
     flags |= 0x08;  // bit3 = shock freeze active
   } else if (idle) {
+    smoothX = smoothY = 0.0f;
     accumX = accumY = 0.0f;
     flags |= 0x01;
   } else {
@@ -437,7 +463,14 @@ void loop() {
     float rawY = applyAcceleration(applyCurve(-fPitch * cfg.sensitivity * dt));
     if (cfg.axisFlip & 0x01) rawX = -rawX;
     if (cfg.axisFlip & 0x02) rawY = -rawY;
-    accumX += rawX; accumY += rawY;
+    // Tiered velocity smoothing: heavy EMA when nearly still, none when fast.
+    // Thresholds are in rad/s (angular rate), independent of sensitivity setting.
+    float speed = sqrtf(fYaw*fYaw + fPitch*fPitch);
+    float alpha = (speed < SMOOTH_LOW_RPS)  ? 0.25f :
+                  (speed < SMOOTH_HIGH_RPS) ? 0.65f : 1.00f;
+    smoothX = smoothX * (1.0f - alpha) + rawX * alpha;
+    smoothY = smoothY * (1.0f - alpha) + rawY * 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;

source/sleep.cpp

@@ -34,6 +34,17 @@ static volatile bool pendingWakeRecal  = false;  // set only when recal is also
 // 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);
@@ -238,15 +249,43 @@ bool sleepManagerUpdate(unsigned long nowMs, bool idle, bool bleConnected) {
     }
   }
 
-  // Gyro settling after wake 
+  // Post-wake recalibration — gated on device being still
   if (pendingWakeRecal) {
-    if (nowMs - wakeSettleMs >= 120) {
-      pendingWakeRecal = false;
-      wakeSettleMs     = 0;
-      extern void calibrateGyroBias();
-      calibrateGyroBias();
-      Serial.println("[SLEEP] Post-wake recal done");
+    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;
   }
 

web/app.js

@@ -19,7 +19,7 @@ const FLAG_ALL_DEFAULT        = FLAG_TAP_ENABLED | FLAG_TEMP_COMP_ENABLED | FLAG
 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,
-                 btnLeftPin:0xFF, btnRightPin:0xFF, btnMiddlePin:0xFF };
+                };
 
 let device=null, server=null, chars={}, userDisconnected=false;
 let currentChargeStatus=0, currentBattPct=null, currentBattVoltage=null;
@@ -247,13 +247,6 @@ async function readConfigBlob() {
     } else {
       config.featureFlags = FLAG_ALL_DEFAULT;  // old firmware - assume all on
     }
-    if (view.byteLength >= 28) {
-      config.btnLeftPin   = view.getUint8(25);
-      config.btnRightPin  = view.getUint8(26);
-      config.btnMiddlePin = view.getUint8(27);
-    } else {
-      config.btnLeftPin = config.btnRightPin = config.btnMiddlePin = 0xFF;  // disabled
-    }
     applyConfigToUI();
     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'); }
@@ -285,38 +278,8 @@ function applyConfigToUI() {
   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);
-  document.getElementById('btnLeftPin').value   = config.btnLeftPin;
-  document.getElementById('btnRightPin').value  = config.btnRightPin;
-  document.getElementById('btnMiddlePin').value = config.btnMiddlePin;
-  updatePinDiagram();
 }
 
-// XIAO pin diagram 
-function updatePinDiagram() {
-  const st = getComputedStyle(document.documentElement);
-  const COL_L = st.getPropertyValue('--ok').trim();
-  const COL_R = st.getPropertyValue('--accent2').trim();
-  const COL_M = st.getPropertyValue('--accent').trim();
-  const DEF_F = '#0c1828', DEF_S = '#162234';
-
-  for (let i = 0; i <= 10; i++) {
-    const el = document.getElementById(`xiaoPin${i}`);
-    if (el) { el.setAttribute('fill', DEF_F); el.setAttribute('stroke', DEF_S); }
-  }
-
-  const apply = (pin, col) => {
-    if (pin > 10) return;
-    const el = document.getElementById(`xiaoPin${pin}`);
-    if (el) { el.setAttribute('fill', col); el.setAttribute('stroke', col); }
-  };
-
-  const l = parseInt(document.getElementById('btnLeftPin').value,   10);
-  const r = parseInt(document.getElementById('btnRightPin').value,  10);
-  const m = parseInt(document.getElementById('btnMiddlePin').value, 10);
-  if (l <= 10) apply(l, COL_L);
-  if (r <= 10) apply(r, COL_R);
-  if (m <= 10) apply(m, COL_M);
-}
 
 let _writeConfigTimer = null;
 function writeConfigBlob() {
@@ -344,11 +307,7 @@ async function _doWriteConfigBlob() {
                        | (document.getElementById('capAutoRecal').checked   ? FLAG_AUTO_RECAL_ENABLED : 0);
   // config.curve, config.chargeMode, config.tapAction, config.tapKey updated directly
 
-  config.btnLeftPin   = parseInt(document.getElementById('btnLeftPin').value,   10);
-  config.btnRightPin  = parseInt(document.getElementById('btnRightPin').value,  10);
-  config.btnMiddlePin = parseInt(document.getElementById('btnMiddlePin').value, 10);
-
-  const buf  = new ArrayBuffer(28);
+  const buf  = new ArrayBuffer(25);
   const view = new DataView(buf);
   view.setFloat32(0,  config.sensitivity,   true);
   view.setFloat32(4,  config.deadZone,      true);
@@ -363,9 +322,6 @@ async function _doWriteConfigBlob() {
   view.setUint8(19, config.tapFreezeEnabled);
   view.setFloat32(20, config.jerkThreshold, true);
   view.setUint8(24, config.featureFlags);
-  view.setUint8(25, config.btnLeftPin);
-  view.setUint8(26, config.btnRightPin);
-  view.setUint8(27, config.btnMiddlePin);
 
   try {
     await gattWrite(chars.configBlob, buf);
@@ -661,7 +617,7 @@ function setStatus(state) {
   pill.className='status-pill '+state;
   document.body.className=state;
   const cBtn=document.getElementById('connectBtn'), dBtn=document.getElementById('disconnectBtn');
-  const inputs=document.querySelectorAll('input[type=range],.seg-btn,.toggle input,.cmd-btn,#tapKeyHex,.mod-btn input,.pin-select');
+  const inputs=document.querySelectorAll('input[type=range],.seg-btn,.toggle input,.cmd-btn,#tapKeyHex,.mod-btn input');
   if (state==='connected') {
     cBtn.style.display='none'; dBtn.style.display='';
     inputs.forEach(el=>el.disabled=false);
@@ -1043,7 +999,6 @@ function applyTheme(t) {
   localStorage.setItem('theme', t);
   if (!chars.imuStream) drawInitState();
   orientUpdateColors();
-  updatePinDiagram();
 }
 (function(){
   const saved = localStorage.getItem('theme') ?? 'auto';
@@ -1060,3 +1015,35 @@ 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

@@ -180,122 +180,6 @@
       </div>
     </div>
 
-    <div class="section-label">Physical Buttons</div>
-    <div class="card">
-      <!--  XIAO nRF52840 Sense pin diagram  -->
-      <div class="xiao-wrap">
-        <svg id="xiaoSvg" viewBox="0 0 200 278" xmlns="http://www.w3.org/2000/svg" style="display:block;width:100%;max-width:200px">
-          <!-- USB-C connector -->
-          <rect x="72" y="4" width="56" height="28" rx="7" fill="#080e18" stroke="#162234" stroke-width="1.5"/>
-          <rect x="82" y="10" width="36" height="5" rx="1.5" fill="#0e1c30"/><rect x="82" y="18" width="36" height="5" rx="1.5" fill="#0e1c30"/>
-          <text x="100" y="30" text-anchor="middle" font-size="5.5" fill="#162234" font-family="Share Tech Mono,monospace">USB·C</text>
-          <!-- PCB board -->
-          <rect x="22" y="29" width="156" height="244" rx="9" fill="#080e18" stroke="#142030" stroke-width="1.5"/>
-          <!-- Corner holes -->
-          <circle cx="34"  cy="41"  r="3.5" fill="#040810" stroke="#0e1c2c" stroke-width="0.8"/>
-          <circle cx="166" cy="41"  r="3.5" fill="#040810" stroke="#0e1c2c" stroke-width="0.8"/>
-          <circle cx="34"  cy="261" r="3.5" fill="#040810" stroke="#0e1c2c" stroke-width="0.8"/>
-          <circle cx="166" cy="261" r="3.5" fill="#040810" stroke="#0e1c2c" stroke-width="0.8"/>
-          <!-- Board silk label -->
-          <text x="100" y="52" text-anchor="middle" font-size="5.5" fill="#142030" font-family="Share Tech Mono,monospace">XIAO nRF52840 Sense</text>
-          <!-- Antenna outline -->
-          <rect x="130" y="34" width="34" height="22" rx="2" fill="none" stroke="#0e1c2c" stroke-width="0.7" stroke-dasharray="2,2"/>
-          <text x="147" y="48" text-anchor="middle" font-size="5" fill="#0e1c2c" font-family="Share Tech Mono,monospace">ANT</text>
-          <!-- SoC -->
-          <rect x="60" y="78" width="80" height="72" rx="3" fill="#0c1828" stroke="#142030" stroke-width="0.8"/>
-          <text x="100" y="112" text-anchor="middle" font-size="7" fill="#1e3858" font-family="Share Tech Mono,monospace" font-weight="bold">nRF52840</text>
-          <text x="100" y="123" text-anchor="middle" font-size="5.5" fill="#102030" font-family="Share Tech Mono,monospace">HOLYIOT</text>
-          <!-- BGA dots (decorative) -->
-          <g fill="#0c1a2a"><circle cx="74" cy="94" r="1.8"/><circle cx="82" cy="94" r="1.8"/><circle cx="90" cy="94" r="1.8"/><circle cx="98" cy="94" r="1.8"/><circle cx="106" cy="94" r="1.8"/><circle cx="114" cy="94" r="1.8"/><circle cx="74" cy="102" r="1.8"/><circle cx="82" cy="102" r="1.8"/><circle cx="90" cy="102" r="1.8"/><circle cx="98" cy="102" r="1.8"/><circle cx="106" cy="102" r="1.8"/><circle cx="114" cy="102" r="1.8"/><circle cx="74" cy="140" r="1.8"/><circle cx="82" cy="140" r="1.8"/><circle cx="90" cy="140" r="1.8"/><circle cx="98" cy="140" r="1.8"/><circle cx="106" cy="140" r="1.8"/><circle cx="114" cy="140" r="1.8"/></g>
-          <!-- IMU chip -->
-          <rect x="72" y="176" width="56" height="44" rx="3" fill="#0a1420" stroke="#122030" stroke-width="0.8"/>
-          <text x="100" y="196" text-anchor="middle" font-size="5.5" fill="#142030" font-family="Share Tech Mono,monospace">LSM6DS3</text>
-          <text x="100" y="207" text-anchor="middle" font-size="5" fill="#0e1c2c" font-family="Share Tech Mono,monospace">IMU</text>
-          <!-- Charger IC -->
-          <rect x="36" y="228" width="30" height="26" rx="2" fill="#0a1420" stroke="#122030" stroke-width="0.8"/>
-          <text x="51" y="244" text-anchor="middle" font-size="4.5" fill="#0e1c2c" font-family="Share Tech Mono,monospace">BQ25100</text>
-          <!-- LED indicators -->
-          <circle cx="142" cy="168" r="3.5" fill="#0a1a0a" stroke="#0e180e" stroke-width="0.8"/>
-          <circle cx="152" cy="168" r="3.5" fill="#1a0a0a" stroke="#180e0e" stroke-width="0.8"/>
-          <circle cx="162" cy="168" r="3.5" fill="#0a0a1a" stroke="#0e0e18" stroke-width="0.8"/>
-          <text x="152" y="178" text-anchor="middle" font-size="4.5" fill="#0e1c2c" font-family="Share Tech Mono,monospace">LED</text>
-          <!-- Left traces -->
-          <g stroke="#142030" stroke-width="2"><line x1="22" y1="62" x2="9" y2="62"/><line x1="22" y1="94" x2="9" y2="94"/><line x1="22" y1="126" x2="9" y2="126"/><line x1="22" y1="158" x2="9" y2="158"/><line x1="22" y1="190" x2="9" y2="190"/><line x1="22" y1="222" x2="9" y2="222"/><line x1="22" y1="254" x2="9" y2="254"/></g>
-          <!-- Right traces -->
-          <g stroke="#142030" stroke-width="2"><line x1="178" y1="62" x2="191" y2="62"/><line x1="178" y1="94" x2="191" y2="94"/><line x1="178" y1="126" x2="191" y2="126"/><line x1="178" y1="158" x2="191" y2="158"/><line x1="178" y1="190" x2="191" y2="190"/><line x1="178" y1="222" x2="191" y2="222"/><line x1="178" y1="254" x2="191" y2="254"/></g>
-          <!-- Left pads D0-D6 (arduino 0-6) -->
-          <circle id="xiaoPin0" cx="9" cy="62"  r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <circle id="xiaoPin1" cx="9" cy="94"  r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <circle id="xiaoPin2" cx="9" cy="126" r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <circle id="xiaoPin3" cx="9" cy="158" r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <circle id="xiaoPin4" cx="9" cy="190" r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <circle id="xiaoPin5" cx="9" cy="222" r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <circle id="xiaoPin6" cx="9" cy="254" r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <!-- Right pads D7-D10 (arduino 7-10) -->
-          <circle id="xiaoPin7"  cx="191" cy="62"  r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <circle id="xiaoPin8"  cx="191" cy="94"  r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <circle id="xiaoPin9"  cx="191" cy="126" r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <circle id="xiaoPin10" cx="191" cy="158" r="7" fill="#0c1828" stroke="#162234" stroke-width="1.5"/>
-          <!-- RST / GND / 3V3 (non-configurable) -->
-          <circle cx="191" cy="190" r="7" fill="#0c1828" stroke="#102028" stroke-width="1.5"/>
-          <circle cx="191" cy="222" r="7" fill="#0c1828" stroke="#201010" stroke-width="1.5"/>
-          <circle cx="191" cy="254" r="7" fill="#0c1828" stroke="#102010" stroke-width="1.5"/>
-          <!-- Left labels D0-D6 -->
-          <g font-size="7" font-family="Share Tech Mono,monospace" fill="#1e3858"><text x="24" y="65">D0</text><text x="24" y="97">D1</text><text x="24" y="129">D2</text><text x="24" y="161">D3</text><text x="24" y="193">D4</text><text x="24" y="225">D5</text><text x="24" y="257">D6</text></g>
-          <g font-size="5.5" font-family="Share Tech Mono,monospace" fill="#112030"><text x="36" y="65">A0</text><text x="36" y="97">A1</text><text x="36" y="129">A2</text><text x="36" y="161">A3</text><text x="36" y="193">SDA</text><text x="36" y="225">SCL</text><text x="36" y="257">TX</text></g>
-          <!-- Right labels D7-D10 -->
-          <g font-size="7" font-family="Share Tech Mono,monospace" text-anchor="end" fill="#1e3858"><text x="176" y="65">D7</text><text x="176" y="97">D8</text><text x="176" y="129">D9</text><text x="176" y="161">D10</text></g>
-          <g font-size="5.5" font-family="Share Tech Mono,monospace" text-anchor="end" fill="#112030"><text x="162" y="65">RX</text><text x="162" y="97">SCK</text><text x="162" y="129">MISO</text><text x="162" y="161">MOSI</text></g>
-          <!-- RST/GND/3V3 labels -->
-          <g font-size="7" font-family="Share Tech Mono,monospace" text-anchor="end" fill="#0e1c2c"><text x="176" y="193">RST</text></g>
-          <g font-size="7" font-family="Share Tech Mono,monospace" text-anchor="end" fill="#1a0808"><text x="176" y="225">GND</text></g>
-          <g font-size="7" font-family="Share Tech Mono,monospace" text-anchor="end" fill="#081a08"><text x="176" y="257">3V3</text></g>
-        </svg>
-        <div class="pin-legend">
-          <span class="pleg left">● Left</span>
-          <span class="pleg right">● Right</span>
-          <span class="pleg mid">● Middle</span>
-        </div>
-      </div>
-      <hr class="xiao-divider">
-      <div class="flip-row" style="align-items:center;padding-top:4px">
-        <div class="flip-label">Left Click</div>
-        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Pin wired to GND when pressed</div>
-        <select class="pin-select" id="btnLeftPin" onchange="updatePinDiagram();writeConfigBlob()" disabled>
-          <option value="255">None</option>
-          <option value="0">D0</option><option value="1">D1</option><option value="2">D2</option>
-          <option value="3">D3</option><option value="4">D4</option><option value="5">D5</option>
-          <option value="6">D6</option><option value="7">D7</option><option value="8">D8</option>
-          <option value="9">D9</option><option value="10">D10</option>
-        </select>
-      </div>
-      <div class="flip-row" style="align-items:center">
-        <div class="flip-label">Right Click</div>
-        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Pin wired to GND when pressed</div>
-        <select class="pin-select" id="btnRightPin" onchange="updatePinDiagram();writeConfigBlob()" disabled>
-          <option value="255">None</option>
-          <option value="0">D0</option><option value="1">D1</option><option value="2">D2</option>
-          <option value="3">D3</option><option value="4">D4</option><option value="5">D5</option>
-          <option value="6">D6</option><option value="7">D7</option><option value="8">D8</option>
-          <option value="9">D9</option><option value="10">D10</option>
-        </select>
-      </div>
-      <div class="flip-row" style="align-items:center;border-bottom:none">
-        <div class="flip-label">Middle Click</div>
-        <div class="param-desc" style="flex:1;font-size:9px;color:var(--label)">Pin wired to GND when pressed</div>
-        <select class="pin-select" id="btnMiddlePin" onchange="updatePinDiagram();writeConfigBlob()" disabled>
-          <option value="255">None</option>
-          <option value="0">D0</option><option value="1">D1</option><option value="2">D2</option>
-          <option value="3">D3</option><option value="4">D4</option><option value="5">D5</option>
-          <option value="6">D6</option><option value="7">D7</option><option value="8">D8</option>
-          <option value="9">D9</option><option value="10">D10</option>
-        </select>
-      </div>
-      <div style="padding:8px 0 2px;font-size:9px;color:var(--label);font-family:var(--mono)">
-        Pull-up built-in · wire button between chosen pin and GND
-      </div>
-    </div>
-
     <div class="section-label">Device Commands</div>
     <div class="cmd-grid">
       <button class="cmd-btn calibrate" id="btnCal" onclick="sendCalibrate()" disabled>
@@ -308,6 +192,29 @@
       </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>
 
@@ -365,6 +272,7 @@
   </div>
 </main>
 
+
 <div class="overlay" id="overlay">
   <div class="modal">
     <h3>⚠ Factory Reset</h3>

web/style.css

@@ -153,13 +153,6 @@
   .col-mid   { display:grid; gap:12px; }
   .col-right { display:grid; gap:12px; position:sticky; top:80px; }
 
-  /*  XIAO pin diagram  */
-  .xiao-wrap { display:flex; flex-direction:column; align-items:center; padding:8px 0 14px; }
-  .pin-legend { display:flex; gap:20px; justify-content:center; font-family:var(--mono); font-size:9px; margin-top:10px; letter-spacing:0.08em; }
-  .pleg.left   { color:var(--ok); }
-  .pleg.right  { color:var(--accent2); }
-  .pleg.mid    { color:var(--accent); }
-  .xiao-divider { border:none; border-top:1px solid var(--border); margin:0 -20px 12px; }
 
   /*  Responsive  */
   @media (max-width:1100px) {
@@ -315,6 +308,7 @@
   .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; }
@@ -325,11 +319,28 @@
   .mod-btn input:disabled + span { opacity:0.35; cursor:not-allowed; }
 
   .restart-note { color:var(--warn); font-family:var(--mono); font-size:9px; }
-  .pin-select { background:var(--bg); color:var(--text); border:1px solid var(--border); font-family:var(--mono); font-size:11px; padding:3px 6px; cursor:pointer; min-width:80px; }
-  .pin-select:disabled { color:var(--dim); border-color:var(--dim); cursor:not-allowed; }
+
 
   .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); }