Phone Orientation Sensor Test
If the screen will not rotate or a level app looks wrong, start by watching how the phone responds as you tilt it. This phone sensor test displays the orientation angles the browser receives and moves a bubble with them. It gives you something to compare with the behaviour that brought you here.
A changing reading is useful evidence that data is arriving. A frozen zero needs more checking: it can mean missing data or a permission problem. Give the page access when asked, then move the phone slowly. This check alone cannot tell you whether an accelerometer or gyroscope needs repair.
Accelerometer, gyroscope, magnetometer — what each one does
Phones carry three motion chips, and people use the names interchangeably.
- Accelerometer — linear acceleration on three axes, gravity included. At rest it sees about 9.81 m/s² pointing down, which is how it derives absolute tilt. It never drifts, but its zero point shifts with age or a hard drop.
- Gyroscope — the rate of rotation in degrees per second. Fast and unbothered by shaking, which is why games and AR lean on it. Its weakness is drift, and budget phones sometimes omit it.
- Magnetometer — a compass. Slow, and easily wrecked by a magnetic case or a steel desk.
The system fuses all three into one estimate, and that is what a web page receives — the same answer every other app gets, so a fault anywhere shows up in it.
Reading the live values: alpha, beta and gamma
The numbers under the bubble are orientation angles in degrees. Beta follows pitch as you tip the phone toward or away from you. Gamma follows roll as you tilt it onto an edge. Alpha describes rotation around the vertical axis, so it does not have to be zero when the phone lies flat.
Move slowly through a few positions and look for readings that change with your hand. A zero that stays fixed does not prove the phone is level: first check permission and whether the page is receiving data. For a broader check, use the phone test online suite.
Reading the bubble level
Set the phone face up on a steady surface and watch the bubble, then tilt the phone gently. The useful comparison is whether the display follows a movement you can repeat.
A bubble away from the centre is a reason to check the setup. The surface and the way the phone rests both matter. This page has no calibrated reference with which to certify the sensor. If the same mismatch also appears in another app, note the conditions before contacting support; a screenshot of one angle without that context says very little.
Why auto-rotate stops working
Work through the causes in this order, because the sensor is the least likely one. First, rotation lock: the padlock icon in iPhone's Control Center, or the Auto-rotate tile in Android Quick Settings. Second, the app: plenty are portrait-only by design, so rotation failing in one app while Safari and Photos work is not a fault. Third, Android's face-detection option, which holds orientation when it thinks you are lying down.
Only then suspect hardware, and a dead motion chip rarely goes alone: it takes the compass needle, Back Tap and step counting with it. Three symptoms arriving together after one update is one failing part, not three coincidences. A screen that rotates when it should not is the same fault from the other side; rule out the digitiser with a touch screen test.
Gyro drift, and why your aim creeps in games
Gyro drift is physics, not a defect. The gyroscope reports rotation rate, and angle comes from adding those rates up, so a constant offset accumulates without limit: a bias of 0.5°/s becomes 30° of error after a minute. Bias also shifts with temperature, which is why gyro aim feels fine early and starts creeping twenty minutes into a hot phone.
You never see it day to day, because the system corrects the gyroscope against gravity and north. Games reading the gyro directly get no correction, which is why their settings tell you to recalibrate flat first.
How to recalibrate the sensors on Android and iOS
Re-zeroing takes a minute, and the device must stay flat, still and untouched throughout — a resting finger is the usual reason it fails to stick.
Android
Samsung: dial *#0*# in the Phone app, choose Sensor, then Gyro Selftest, hands off. Many Xiaomi, Redmi and Poco models use *#*#64663#*#* for a hardware-detection menu with accelerometer and gyroscope calibration: start it, wait for X, Y and Z to settle, then end it. Other makers bury an equivalent under motions or diagnostics; some omit it, leaving a reboot as the only option. One myth worth killing: the figure-eight wave calibrates the magnetometer and nothing else.
iOS
Apple exposes no gyroscope or accelerometer calibration, and the Compass app's rolling-ball routine calibrates the magnetometer only, so it will not fix a tilted level. What you have is a restart, which makes iOS recompute sensor bias at boot, then Reset All Settings. Still off after both, treat it as hardware — no app can write a new calibration to the chip.
What this browser test cannot tell you
A web page sits several layers above the sensor, and those layers impose real limits.
- iPhone and iPad need your permission first. Since iOS 13, Safari delivers no motion data until the page calls
DeviceOrientationEvent.requestPermission()from inside a genuine user gesture (a real tap), and only over HTTPS — it is a secure-context API, so the events never fire over plain HTTP. This page makes that call: tap “Start sensor test” and allow Motion & Orientation Access, and the angles and bubble come alive. Decline it and the page tells you so instead of sitting silently at zero — re-enable it under Settings → Safari → Motion & Orientation Access, or clear this site under Settings → Safari → Advanced → Website Data, then reload and tap again. - In-app browsers block it too. Links opened inside Instagram, Facebook, TikTok and other WebView wrappers deliver no motion data. Open the page in Safari or Chrome directly.
- You get fused degrees, not raw data. No web page can read acceleration in m/s², angular rate in °/s or the true sampling rate; browsers cap the event rate near 60 Hz.
- Zero on a desktop means "no sensor". Most laptops have no accelerometer.
Frozen angles in a normal browser over HTTPS — on Android, or on an iPhone after you have allowed the prompt — are meaningful. Pair that with a vibration test before booking a repair — the motion sensors and the vibration motor share a board.
Frequently asked questions
Why is auto rotation not working on my iPhone?
Check rotation lock first — it causes this far more often than a dead sensor. Open Control Center and make sure the padlock-and-arrow icon is off, then confirm the app supports landscape at all, since many are portrait-only by design. If rotation fails everywhere including Safari and Photos, open the Compass app: a frozen needle alongside broken rotation means the motion hardware itself, and a restart is the next step before service.
My gyroscope stopped working while playing PUBG — how do I fix it?
Re-zero the gyro before you touch any in-game setting. Put the phone flat and untouched and run the maker's self-test — on Samsung dial *#0*#, then Sensor, then Gyro Selftest. Next check the game: gyroscope must be set to Scope On or Always On under Settings → Sensitivity. Finally turn off battery-saver modes, which throttle sensor sampling, and let the phone cool — heat degrades gyro output during long matches.
My phone thinks it is tilted when it is lying flat — is the accelerometer broken?
Almost certainly not broken, just biased. A MEMS accelerometer's zero point drifts a degree or two with age, temperature or a drop, so apps read a tilt that is not really there. Confirm it properly: note the angle, rotate the phone 180° on the same spot, and read again. If the error flips sign the phone is off; if it points the same way your table is sloped. Under about 2° is normal.
How do I know if I have a gyroscope on my Android phone?
Look up your exact model number on the maker's spec page — that is the only definitive answer, and budget phones and older tablets genuinely do ship without one. As a practical check, play a 360° video and pan by moving the phone: a gyroscope tracks fast turns smoothly, while a phone relying on accelerometer and compass alone lags and jitters. No gyroscope also means AR modes in games like Pokémon GO will not run.
How can I force a gyroscope recalibration?
On Android, use the maker's built-in routine with the phone flat and untouched: Samsung is *#0*# → Sensor → Gyro Selftest, and many Xiaomi and Redmi models use *#*#64663#*#* for accelerometer and gyroscope calibration. On iOS there is no gyroscope calibration at all — the Compass app's rolling-ball routine only calibrates the magnetometer. A restart recomputes sensor bias at boot; after that, Reset All Settings, then service.
Why does the motion sensor show nothing on my iPhone in Safari?
iOS blocks it until you say yes. Since iOS 13 Safari delivers no motion data until the page calls DeviceOrientationEvent.requestPermission() from inside a real tap, over HTTPS. This page does make that call, so tap “Start sensor test” and choose Allow on the Motion & Orientation prompt. Nothing at all happens? You are probably in an in-app browser (Instagram, Facebook, TikTok) or on an http:// link — open the page in Safari or Chrome over HTTPS. Already declined once? The prompt will not come back by itself: turn Motion & Orientation Access back on under Settings → Safari, or clear this site under Settings → Safari → Advanced → Website Data, then reload.
My accelerometer and gyroscope stopped working after an update — what now?
Restart before anything else, then check what else died at the same moment. A frozen compass needle, a dead Back Tap and broken rotation appearing together point at one failing component or its driver, not three separate software bugs. If a restart and Reset All Settings do not bring them back, treat it as hardware: an update can expose a sensor that was already failing, but it rarely kills a healthy one.