Accelerometer (m/s²)

Gyroscope (°/s)

Magnetometer (μT)

A true magnetometer feed requires Android with the Generic Sensor API; on iOS the only available channel is compass heading, shown here as a single trace.

Tilt: complementary filter (°)

The accelerometer reads the gravity vector, so it gives clean tilt at rest but is corrupted by linear motion. The gyroscope reads angular rate, smooth and responsive but its integral drifts. A complementary filter trusts the gyro at short timescales and the accel at long ones: θ = α · (θ_prev + ω · Δt) + (1 − α) · θ_accel.

Slide α toward 1 to favour the gyro (smooth, drifty); toward 0 to favour the accel (jittery, no drift).

Pitch (rotation around phone X — tilting top edge up/down)

Roll (rotation around phone Y — tilting left/right edge down)

Try shaking the phone in place — the accel trace jumps around while gyro stays calm. Now hold it steady at an angle for a while — the gyro trace slowly walks away from truth while accel stays anchored. The complementary trace stays both smooth and anchored.

Orientation (°, from DeviceOrientationEvent)

α (yaw / Z) —

β (pitch / X) —

γ (roll / Y) —

Waiting for phone…

3D box

Racing

Hold the phone roughly in front of you and tilt it like a steering wheel. Stay on the grey strip for full speed; leave it and you slow down. Cross the chequered line at the bottom to record a lap.

Display