Phone sensor board
A compass, a bubble level, a speed and distance tracker for walking or cycling, and your altitude, all from your phone's own sensors.
Everything stays on your phone. Your location and movements are not uploaded or saved.
CompassQibla direction →
Hold the phone flat, top edge pointing ahead. It shows magnetic north. Keep away from metal, magnets and car dashboards, and wave the phone in a figure-of-eight if it seems wrong.
Bubble level
Speed and distance
Keep this page open with the screen on: most browsers pause GPS in the background. Works best outdoors with a clear view of the sky. Don't look at the screen while cycling or crossing roads.
Altitude
From GPS, while speed and distance is running. GPS height is measured above a mathematical model of the Earth (the WGS84 ellipsoid), so it can differ from height above sea level, and it is less exact than position. Some phones and browsers don't give it at all.
What is measuring what
A tiny magnetic sensor feels the Earth's magnetic field. Metal and electronics nearby bend it, which is why it can be off indoors or in a car.
At rest, the accelerometer feels only gravity, so the phone knows which way is down. The tilt is worked out from how gravity splits across the phone's three axes.
GPS works out your position from satellite signals each second. Distance adds up the small steps between fixes and ignores jumps smaller than the uncertainty, so standing still doesn't add distance.
This page reads the sensors in your browser and sends nothing anywhere. The browser asks for permission first, and you can withdraw it in its settings at any time.
Sources: W3C Geolocation specification (accuracy as a radius in metres; altitude in metres above the WGS84 ellipsoid; speed as the horizontal speed in metres per second); W3C DeviceOrientation Event specification (device axes, accelerationIncludingGravity of about 9.8 m/s² on the z axis when flat and face up, and the permission request needed on some phones); Wikipedia, "Preferred walking speed" (typical 1.4 m/s, about 5 km/h; usual range about 4 to 5.9 km/h). Readings depend on your phone's sensors: this is a handy guide, not a surveying or navigation instrument.