How to compare motion sensor responses across phones

One phone reacts quickly when you tilt it, while another seems delayed or reports different directions. That can be a sensor difference, but the browser, phone orientation, permissions, or surroundings can change what you see too.

Use the Sensors Test on each phone, under the same conditions. This gives you a practical comparison of motion, gyroscope, compass, light, location, and vibration responses. It is not a laboratory calibration, but it can help you spot a sensor that is missing, erratic, or noticeably different.

Compare the phones under the same conditions

1. Open the Sensors Test on the first phone. Allow the browser to access sensors when asked. Open the same test on the second phone, preferably in the same browser, and grant the same permissions.
2. Place both phones on the same stable surface, in the same orientation. Keep them still for a moment and note which readings appear and whether they settle or keep changing.
3. Compare motion and gyroscope response with a repeatable movement. Slowly tilt each phone forward, back, and to each side, then rotate it a similar amount. Use the same speed and range of movement for both.
4. For the compass, turn each phone through the same directions while keeping it away from metal objects, speakers, and magnetic cases. For the light sensor, compare the phones side by side in the same lighting, without covering either one.
5. If you are checking location or vibration, test those separately. Location needs permission and may take time to update. Vibration depends on the phone and browser, so an unavailable response does not by itself prove a fault.
6. Repeat the sequence once more, and then swap which phone you test first. A difference that appears consistently is more useful than a single reading or movement.

Do not shake the phones hard or twist them forcefully. Slow, controlled movement is easier to repeat and safer for the devices.

What the result means

Both phones respond smoothly in a similar way

The tested sensors are responding to movement. Their numbers do not need to match exactly: phones can use different sensor hardware, calibration, filtering, and coordinate conventions. A similar change as you tilt or rotate each phone matters more than identical values.

One phone responds later or changes in jumps

Repeat the movement at a steady pace. If the delay or jumps happen again on that phone, the browser may be receiving updates less often, or the phone may be filtering the sensor data differently. Close other apps, reload the test, and compare again before assuming the sensor is damaged.

The compass direction differs

First move both phones away from magnetic cases, metal tables, speakers, and other sources of interference. Compass readings can also need calibration, and the phones may be held at slightly different angles. A direction mismatch in one room is not enough to show that a compass is faulty.

A sensor is missing or the test shows no response

The phone may not expose that sensor to the browser, or permission may be blocked. Some phones do not include every sensor, and mobile browsers do not all allow the same access. Check permissions and try another supported browser before treating this as a hardware problem. For more on browser limits, see why a mobile browser cannot access every sensor.

Readings change while the phone is still

Small changes can be normal. A phone can shift slightly on the surface, and sensors can report minor noise even when you are not moving it. If the values jump widely while the phone rests on a firm surface, repeat the check in another place and browser. A test must run on the device being checked, as explained in why a sensor test must run on the device being checked.

How to fix an inconsistent comparison

1. Match the setup. Use the same browser, keep both phones in the same orientation, and test them in the same place. Remove magnetic cases if compass results differ.
2. Allow the browser to use sensors. If the browser asks for motion or orientation access, choose Allow. If you previously blocked it, open the site permission controls from the browser's address bar and change the relevant permission, if available. Reload the page afterward.
3. Check Safari's motion setting. On an iPhone using Safari, open Settings › Safari › Motion & Orientation Access and turn it on if the setting is present. The exact controls can vary by iOS version and browser.
4. Allow location only if you are testing it. On Android, check Settings › Apps › [your browser] › Permissions › Location, then allow the site to use location in the browser prompt. On iPhone, check Settings › Privacy & Security › Location Services › Safari Websites. You can skip location permission when comparing movement sensors.
5. Restart the browser. Close the browser fully, reopen it, and run the test again. This can clear a stuck permission or a temporary browser issue.
6. Update the phone and browser. Install available updates, restart the phone, and repeat the same comparison. If the result remains different, test the phone in another browser that supports sensor access.

When it may be a hardware problem

A browser test alone cannot confirm that a sensor is broken. Suspect a hardware problem when the same sensor stays unavailable or behaves erratically across more than one browser, after permissions are allowed, and in several locations. If the issue began after a drop or liquid exposure, avoid further testing that could risk damage and contact the manufacturer or a repair shop. If the phone is under warranty, ask the manufacturer to diagnose it.

Why exact readings may not match

Motion sensors describe movement relative to the phone, so the axes can look different if one device is turned around. The operating system may also smooth rapid changes before the browser receives them. Compass readings are especially sensitive to the room, while light readings depend on where each phone's sensor sits and whether a hand or case shades it.

For a fair comparison, look for repeatable behavior: both phones should react in the expected direction, settle when left still, and respond consistently to the same gentle movement.