How to use
- Open this page on your phone and tap Start sensors. On iPhone, allow the permission request.
- Lay the phone flat on a table. The bubble should be centred and the accelerometer Z about 9.8.
- Tilt and turn the phone and check that the gyroscope and compass readings follow.
Options explained
- Accelerometer
- Acceleration on three axes including gravity, in m/s². Lying flat and still, X and Y are near 0 and Z near 9.8.
- Gyroscope
- Rotation speed around three axes, in degrees per second; all near 0 when still.
- Compass
- The angle between the top of the phone and true north. Some Android browsers only give relative orientation, so no heading is shown.
What each panel shows
| Panel | What it displays | When the phone lies flat and still |
|---|---|---|
| Spirit level | Front–back and left–right tilt in degrees. The bubble reaches the edge of the circle at 45° and the ring and bubble turn green when both angles are within 1° of zero. | Bubble centred, both angles near 0° |
| Accelerometer (m/s², with gravity) | X, Y and Z acceleration, gravity included | X and Y near 0, Z near 9.8 |
| Gyroscope (°/s) | Rotation speed around the three axes, shown as α, β and γ | All three near 0 |
| Compass | A heading in degrees from 0 to 360 | A steady value once you stop turning |
Because gravity is included, the 9.8 moves to whichever axis points up or down when you tilt the phone, and the combined size of X, Y and Z stays near 9.8. On iPhone the compass heading comes from the phone itself; on other phones it is computed as 360 minus the absolute orientation angle, and it shows “No compass heading available” when the browser reports only relative orientation.
The line “Motion events per second” counts how often the browser reports motion data, so you can see how steady the sensor feed is. If nothing arrives within two seconds, the page warns that the device probably has no motion sensors.
Frequently asked questions
Why is there no data on my computer?
Desktops and most laptops have no motion sensors. Use a phone or tablet.
How do I calibrate an inaccurate compass?
Move away from metal and magnets and draw a figure 8 in the air with the phone a few times. Map apps usually prompt for this too.
Nothing happens on Android.
Some browsers only provide sensor data on HTTPS pages when motion sensors are allowed in site settings. Try Chrome.
Privacy
This tool runs entirely in your browser. Your files and text are processed on your device and are never uploaded to our servers.