Ambient Light Sensor (Lux) Test
Read real-time Lux usage. Test auto-brightness hardware.
Control and sampling
recent readings
| time | lux | Remark |
|---|---|---|
| No data yet. Click "Start Listening", then cover/move the sensor with your hand or change the lighting. | ||
Availability and Permissions
event log
Quickly verify automatic brightness linkage
Sensor Guide
Verify sensor readings and auto-brightness reaction.
Prepare environment and system settings
Prioritize testing in a mobile browser + HTTPS environment, and turn on system automatic brightness.
Start listening and confirm that the readings are changing
Click "Start Monitoring" and first check the frequency and update time to confirm that the sensor is indeed reporting.
Make occlusion/illumination changes and compare with automatic brightness linkage
Make a step change in lux by blocking/moving the sensor away or changing the light intensity and see how the system brightness responds.
FAQ
Frequently asked questions about ambient light readings, automatic brightness linkage, and browser compatibility.
What can this page test?
It will try to read the ambient illumination (lux, if supported by the browser/device), and display real-time readings, changing trends, recent records and sampling frequency to help you verify whether the system's automatic brightness/adaptive brightness follows the changes in ambient light, as well as the delay and consistency of the linkage.
Why does it show "not supported"? My phone obviously has automatic brightness.
Very common. Due to privacy/fingerprint recognition risks, many browsers do not expose ambient light sensor readings by default; the fact that the system's automatic brightness is available does not mean that the Web API must be open. It is recommended to change to an environment that may be supported, such as Android Chrome.
What is lux? What range is considered light/dark?
lux is a unit of illuminance (light intensity). Rough reference: dark room/night probably < 10lx; normal indoors 50–300lx; bright office/outdoors on cloudy days 300–2000lx; direct sunlight may be much higher than this. Different equipment sensors and filters will lead to differences in readings. It is recommended to look at "trends" rather than absolute values.
Why does the reading change but the system brightness remains unchanged?
The system's automatic brightness generally has hysteresis and smoothing strategies (to avoid frequent jumps), and will take into account the user's manual adjustment habits, content brightness, HDR, eye protection mode, power saving mode and other factors. You can lengthen the observation time (10–30 seconds), increase the occlusion amplitude, or reset/turn off relevant enhancements in the system before comparing the test.
Why do readings jitter/jump a lot?
Common reasons are light source flicker (LED/PWM), environmental reflection, and device sensor sampling and filtering strategies are different. It is recommended to switch to a stable light source (such as natural light/better lights), or maintain a more stable occlusion method, and observe trends rather than single point values.
What's the use of "dotting"?
"Dot" will record a time mark in the log so that you can compare it during screen recording playback: when did a certain occlusion/removal occur, how many milliseconds/seconds did the system brightness start to change, and whether it is consistent every time.
How about security/privacy? Will the data be uploaded?
Won't. Readings, trend calculations, and logging are done locally in the browser, and your sensor data is not uploaded. It should be noted that some browsers will directly disable the ambient light API due to privacy concerns, which is a browser policy.