# How sensitive is the light sensor?

**URL:** <https://forum.makecode.com/t/how-sensitive-is-the-light-sensor/13401>\
**Category:** micro:bit\
**Created:** [May 2, 2022, 4:51pm UTC](https://forum.makecode.com/t/how-sensitive-is-the-light-sensor/13401 "2022-05-02T16:51:03Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![mrhope](https://avatars.discourse-cdn.com/v4/letter/m/f07891/32.png) [@mrhope](https://forum.makecode.com/u/mrhope)\
**Post date:** [May 2, 2022, 4:51pm UTC](https://forum.makecode.com/t/how-sensitive-is-the-light-sensor/13401/1 "2022-05-02T16:51:03Z")

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Hi all,

I am testing the embedded light sensor on the microbit. It appeared it would only detect values if I have a torch light shining very closely on the LEDs. Is this the same for everyone or am I missing some step that makes it more accurate or sensitive.

I am in a room during the day time, it’s showing 0. I would think it should at least give me some readings since it’s day time, I am not even in complete darkness.  
I can get some readings if I use a torch to shine on the LED but it would only record readings if my torch is like 30 cm from the microbit, beyond that it shows 0 light level.

thanks all,

Regards,  
Mr Hope

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**Author:** ![mrhope](https://avatars.discourse-cdn.com/v4/letter/m/f07891/32.png) [@mrhope](https://forum.makecode.com/u/mrhope)\
**Post date:** [May 18, 2022, 4:59pm UTC](https://forum.makecode.com/t/how-sensitive-is-the-light-sensor/13401/2 "2022-05-18T16:59:17Z")

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I think I figured out, it appears to be working per design. the light sensor on microbit is not really sensitive, a photoresistor would help if you want to detect light with more accuracy.

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**Author:** ![chand51](https://avatars.discourse-cdn.com/v4/letter/c/74df32/32.png) [@chand51](https://forum.makecode.com/u/chand51)\
**Post date:** [September 9, 2022, 5:09pm UTC](https://forum.makecode.com/t/how-sensitive-is-the-light-sensor/13401/3 "2022-09-09T17:09:34Z")

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It happened with me too and I started thinking that something is wrong with my micro:bit.  
Then strangely I tested my Light Sensor sample code in the morning and voila! it worked 🙂  
I was earlier testing it in the night with my room light on.  
Seems microbit LED light sensor is not sensitive to lights other than sun light, but I will keep checking on for different light source.  
Try if it works for you in sunlight.

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**Author:** ![bsiever](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.makecode.com/bsiever/32/1032_2.png) [@bsiever](https://forum.makecode.com/u/bsiever)\
**Post date:** [September 12, 2022, 2:04pm UTC](https://forum.makecode.com/t/how-sensitive-is-the-light-sensor/13401/4 "2022-09-12T14:04:45Z")

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Hi @mrhope and @chand51,

In case you didn’t already know, the micro:bit doesn’t really have a true light sensor. It uses the LED screen to detect light, as mentioned in this video: [https://youtu.be/ii0U\_FMr-Z4](https://youtu.be/ii0U_FMr-Z4) .

Make Magazine had an article on this approach and some of the strengths/weaknesses, including sensitivity to certain frequencies as @chand51 noted: [https://makezine.com/projects/how-to-use-leds-to-detect-light/](https://makezine.com/projects/how-to-use-leds-to-detect-light/) .

Bill