Sensor Test

What this sensor test checks

Phones and tablets know how they are held thanks to a few small motion sensors. When one of them fails, the screen stops rotating, a game drifts on its own, or the map points the wrong way. This test reads them through your browser and checks each one:

• Accelerometer. It feels gravity and movement. At rest it should read 9.81 m/s², with steady values.
• Level. How far the sensor is from true when the phone lies flat, measured in two positions so that a sloping table does not fool the result.
• Gyroscope. It measures rotation. At rest it should read almost zero; when you move, it should follow in every direction.
• Compass. The heading should follow a full turn smoothly, without jumping.

You see every value live, with its unit, plus a phone drawing that tilts with your device, a bubble level and a compass dial. Nothing is installed, and the readings never leave your device.

How to use the sensor test

1. Open this page on the phone or tablet you want to test. On a computer, the page shows a QR code: scan it with your phone’s camera to open the test there. Tablet PCs and 2-in-1 laptops often have motion sensors of their own: the page then tests them, and shows the QR code below the checks in case you want to test your phone instead.
2. On iPhone and iPad, press Allow motion sensors and accept: Safari asks before a page can read them.
3. Watch the live values, then run the three checks in any order:
   • Flat and still: lay the phone on a table, screen up, and let go for six seconds. Then turn it half a turn on the same spot and measure again for the level.
   • Movements: tilt the phone forwards and back, then sideways, then turn it flat. Each direction lights up when the sensors follow.
   • Compass turn: hold the phone flat and turn slowly on the spot for a full circle.
4. Save the results to compare later, for example before and after a repair, or share them with a buyer.

How to read your results

Why two positions for the level

A table is rarely perfectly flat. Measured once, a phone cannot tell its own error from the table’s slope. Turned half a turn on the same spot, the slope changes direction for the sensor while the sensor’s own error does not. Comparing the two readings separates them: the test gives you both.

Gyroscope missing

Some budget phones have no gyroscope. The screen still rotates and most apps work, because the accelerometer does that job, but games that steer by motion and 360° photos will not work properly.

What each sensor does

Troubleshooting

The screen no longer rotates

Check the rotation lock first: on Android in the quick settings, on iPhone in Control Centre. If the lock is off and the accelerometer result is good, an app may be forcing one orientation. If the accelerometer shows no data or reads far from 9.81, restart the phone; a sensor that stays wrong needs a repair.

The compass points the wrong way or jumps

Magnets disturb it: magnetic cases, car mounts, laptop lids and speakers. Move away from them, then wave the phone in a figure eight a few times so that it recalibrates itself.

Games drift on their own

Run the flat and still check. A gyroscope that reports rotation at rest causes slow drift; restarting the phone often clears it. If it remains, the motion settings of the game may offer a recalibration.

No values at all

On iPhone and iPad, press Allow motion sensors and accept. If Safari no longer asks, remove this site’s data in Settings → Apps → Safari → Advanced → Website Data, then reload. On Android, try Chrome. On a computer, no values appear: computers have no motion sensors.

Frequently asked questions

Can a website calibrate my sensors?

No. A page can only read the sensors. Buttons that “calibrate” on websites only shift the numbers they display; the phone itself is unchanged. Phones recalibrate the compass on their own when you wave them in a figure eight.

Why do the values move when the phone is still?

Every sensor has a little noise, and browsers round the values slightly to protect privacy. Small changes in the last digit are normal; the checks allow for them.

Can it test the light or proximity sensor?

No. Browsers no longer give web pages access to these sensors, or only behind settings meant for developers. Pages that claim to read them cannot do it on most phones.

Is it useful when buying a second-hand phone?

Yes. Sensors can be damaged by drops or by a poor screen replacement, and the faults are easy to miss in a shop. Run the three checks and keep the result.

Is anything recorded or sent to TestrHub?

No. The readings stay in your browser. Saved results stay on your device, and a result is only shared if you copy its link.

Which test should I run next?

The vibration test checks the phone’s vibration motor, and the touch screen test checks every part of the screen.