Which sensor APIs does this tool use?
We use the DeviceMotion and DeviceOrientation events (widely supported), and where available the modern Generic Sensor API (Gyroscope, Accelerometer, AmbientLightSensor, LinearAccelerationSensor classes). The Generic Sensor API is more accurate and exposes higher-frequency data, but is currently Chromium-only. Safari and Firefox fall back to the legacy device events, which still give pitch, roll, yaw, and gravity-included acceleration.
Why does iOS show no readings until I tap a button?
Since iOS 13, Apple requires explicit user permission to access motion and orientation sensors. The DeviceMotionEvent.requestPermission() call must run inside a user gesture, which is why our page shows an Enable button. Tap it, choose Allow on the system prompt, and readings appear. Android, Windows, and desktop browsers do not require this gesture — they expose sensors by default on HTTPS pages.
Why is the ambient light sensor blank?
Most browsers have disabled or removed the AmbientLightSensor API for privacy reasons — readings can leak information about your surroundings. Chrome on Android exposes it behind a flag, and a few Linux desktops support it. If you see zero lux or null, your browser is intentionally blocking the API. Use your device's native light meter app for accurate readings.
Are the gyroscope values calibrated?
The gyroscope reports raw angular velocity in radians per second. Device orientation values (alpha, beta, gamma) are filtered by the OS using sensor fusion — combining gyro, accelerometer, and magnetometer. Expect drift of a few degrees per minute on the yaw axis, especially indoors where magnetic interference is high. Lay the device flat for ten seconds before trusting absolute orientation.
Why are values different between my phone and laptop?
Laptops rarely have gyroscopes; most expose only an accelerometer for screen rotation, and many desktops expose nothing at all. Phones and tablets have a full IMU (inertial measurement unit) and report 50-100 samples per second. Convertible 2-in-1 laptops sit in the middle — accelerometer plus orientation but no high-rate gyro.
What pairs well with this sensor test?
The Multi-touch tool tests the other major mobile input system. If readings look noisy, the CPU benchmark can show whether the device is thermally throttling — heat skews IMU calibration. The Battery status page reveals whether sensor polling is draining your battery faster than expected.