IMU

Up to 2 inertial measurement units — accelerometer, gyroscope and temperature at up to 50 Hz, with on-board calibration. No third-party library required.

Requires <PardaloteIMU.h> in the sketch. One extension covers multiple InvenSense MPU and STMicroelectronics LSM6 families — it reads sensor registers directly over I2C.

Supported sensors

new IMU()

The constructor takes the model string.

arduino.add('imu', new IMU('6050'));

attach()

Connects to the sensor over I2C. Call inside on('ready').

arduino.imu.attach(0x68);
arduino.imu.attach(0x68, 21, 22);   // ESP32 custom SDA/SCL

read()

Starts polling the sensor. Handlers receive every sample — there is deliberately no threshold on the IMU: its streams are usually integrated or smoothed in JS, where dropped samples cause drift. The board runs the poll: one I2C transaction per tick, each browser at its own rate (setReadInterval(ms) also works).

arduino.imu.onChange(({ accel, gyro, temp }) => {
    // accel: { x, y, z } in g
    // gyro:  { x, y, z } in °/s
    // temp:  °C
});
arduino.imu.read(20);   // 50 Hz

The original ESP32 chip's I²C peripheral can stall under sustained high-rate reads — on ESP32-WROVER and other older ESP32 boards keep the interval at 50 ms or higher. Newer ESP32 boards (S3, C3, …) and the UNO R4 poll reliably at 20 ms.

setAccelRange() / setGyroRange()

Measurement ranges. Higher range handles bigger motion but reduces resolution. Unknown values are rejected with a console warning; the current range is left unchanged.

calibrate()

Measures and applies zero offsets. Place the sensor flat with Z pointing up first. Offsets are stored on the Arduino and re-sent to any browser that reconnects — no need to recalibrate after a page reload.

arduino.imu.calibrate(200);
arduino.imu.onCalibrate(offsets => {
    // { ax, ay, az, gx, gy, gz } — applied automatically
    // afterwards: accel.z ≈ +1g, gyro ≈ 0
});

Events

Shorthand: onChange(fn), onCalibrate(fn).

State snapshot

Returns { logicalId, model, dof, address, attached, accelRange, gyroRange, accel, gyro, temp, calibrated, calibration }.

See also: IMU example · Troubleshooting