Add motion tracking and calibration features

README.md

@@ -4,7 +4,7 @@ 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
+- **Roll-compensated pointing** - gyro + accelerometer fusion keeps the cursor level however the remote is twisted in the hand
 - **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
@@ -13,7 +13,7 @@ A BLE HID mouse that uses the onboard IMU of a **Seeed XIAO nRF52840 Sense** to
 - **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
+- **Continuous bias tracking** - gyro bias is re-estimated whenever the remote is at rest, so the cursor does not drift
 - **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)
 
@@ -48,7 +48,7 @@ Open `web/index.html` in Chrome or Edge (desktop). Requires Web Bluetooth - enab
 | Parameter | Range | Description |
 |---|---|---|
 | Sensitivity | 100 – 1500 | Cursor speed multiplier |
-| Dead zone | 0.005 – 0.2 rad/s | Noise floor; raise to reduce drift |
+| Dead zone | 0 – 0.1 rad/s | Soft dead zone on smoothed speed; raise to steady the cursor while holding still |
 | Accel strength | 0 – 0.5 | Pointer acceleration multiplier |
 | Curve | Linear / Square / √Sqrt | Response shape for input magnitude |
 | Flip X / Y | on/off | Invert horizontal or vertical axis |
@@ -59,6 +59,18 @@ Open `web/index.html` in Chrome or Edge (desktop). Requires Web Bluetooth - enab
 - **Calibrate Gyro** - recalculates bias offset; hold the device still on a flat surface for ~1 s
 - **Factory Reset** - wipes flash config, restores defaults
 
+**Serial commands** (115200 baud over USB):
+
+| Key | Action |
+|---|---|
+| `c` | Calibrate gyro |
+| `r` | Factory reset |
+| `s` | Toggle 1 Hz tracking stats (sample rate, HID reports, bias, roll, BLE interval); keeps the device awake |
+| `l` | Toggle raw IMU log, one CSV line per sample; keeps the device awake |
+| `d` | 10 s of roll-compensated yaw/pitch rates and roll angle |
+| `t` | Synthetic sweep (right, left, down, up); moves the host cursor and prints the counts sent |
+| `o` | Enter OTA DFU mode |
+
 ## Building
 
 ### Requirements
@@ -84,7 +96,7 @@ All optional features are enabled by `#define` in `source/config.h`. Comment out
 #define FEATURE_IMU_STREAM        // 20 Hz raw IMU stream
 #define FEATURE_TAP_DETECTION     // Hardware tap → click engine
 #define FEATURE_TEMP_COMPENSATION // Gyro drift correction by temperature
-#define FEATURE_AUTO_RECAL        // Auto-recalibrate after 5 min idle
+#define FEATURE_AUTO_RECAL        // Continuous gyro bias tracking while at rest
 #define FEATURE_BATTERY_MONITOR   // ADC battery level + BLE Battery Service
 #define FEATURE_BOOT_LOOP_DETECT  // Crash counter → safe mode
 ```