Mijia Light Sensor

The Mijia Smart Light Sensor is designed to measure ambient light, in order to create scenes and automations based on the available light. You can program an automation, so that when it gets dark, your porch light comes on, or close your smart curtains, for example.

The sensor can measure as much as 83,000 lux or as little as 2 lux. The sensor is ZigBee 3.0 and uses a CR2450 coin battery for power. It can be used outdoor and is waterproof (no details on IP rating yet).

Currently compatible with the new Mi Smart Gateway and the Aqara hub.

The Editor

Editor - Musician, graphic designer and HomeKit aficionado.

16 thoughts on “Mijia Light Sensor

  • 29th December 2019 at 7:08 pm
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    Great stuff! You can add an instructions to the article how to manually connect it to the Aqara hub 😉 It will be useful to have it in one place.

    • 29th December 2019 at 7:10 pm
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      Hi Tomasz, this is just the listing post. I’ll be posting a full review, including instructions etc soon.

      • 4th January 2020 at 11:09 pm
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        I’ve just received the sensors. It’s working the way you’ve said but it’s also available to add it through the Aqara app.

        • 4th January 2020 at 11:10 pm
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          Hi, yes you can add it manually by pressing the hub button 3 times. Did you find a different way to add it?

  • 30th December 2019 at 10:29 am
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    Hi Simon, I have both Aqara Hub and the new Mi Smart Multimode Gateway, I am pretty sure the light sensor is not supported by the current Aqara Hub due to lack of Zigbee 3.0 support. Could you confirm that?

    • 30th December 2019 at 10:43 am
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      It does work with the Aqara hub, as I have it working with it now. It isn’t officially supported but you can add the sensor to the Aqara hub manually, by pressing the button on the Aqara hub three times to begin the pairing process.

  • 30th December 2019 at 11:27 am
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    I just gave it a try, yes it can be added, but the sensor will not be shown in the Mi Home app (no control UI and not listed under the child device list). The Apple Home app, however, will show the sensor, but the stock Apple Home app does not support setting the automation conditions/events from the light sensor directly. One must use a 3rd party HomeKit app to be able to utilize the sensor reading for any scene control.

    The Mi Home app, on the other hand, does provide a much easier setup process and flow control… So not being able to utilize that is a shame…

    • 30th December 2019 at 11:41 am
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      I added the light sensor to my US hub in the Aqara app as there are less regional restrictions.

  • 12th January 2020 at 6:17 pm
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    Got this the other day and haven’t installed it yet. Will try to add it to my Aqara hub in the office tomorrow. Didn’t expect it to be really small. I want to use it to turn on the lights automatically when available light from the windows are just not as bright for the room anymore.

    Where do you suggest is the best place to install this device? I’m thinking of installing it on the ceiling towards the center of the room where everybody sits. Any suggestions? Thanks!

    • 12th January 2020 at 6:59 pm
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      Hello Hiroyuki
      yes, it is quite small, but maybe that’s a good thing. I would suggest keeping it away from direct sunlight as the readings wouldn’t be accurate enough to represent the real brightness of a room, but maybe on the ceiling would be a good idea I think. Although the sensor updates the light reading quite regularly – approximately every 5 seconds – it wouldn’t be useful for and automation that turns lights on if you need them to react quickly. So a motion sensor would be good for fast ‘lights on’ automations. The light sensor is probably good for situations where it can possibly close the curtains and turn the lights on, when it starts to gets dark, for example.

      • 14th January 2020 at 12:31 pm
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        Got one. Set it up without a hitch.

        Because this is an office and we are in a tropical country, whenever the room’s occupied the aircon will definitely be on. So I’m controlling the automation with rules that it will only turn which lights are on/off depending on light condition only when the AC is on. Otherwise all lights will turn off automatically.

        Installed it on the ceiling at the center of the room to monitor the amount of light in the room and did the all automation thru Eve app and it’s working perfectly.

        • 14th January 2020 at 12:41 pm
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          Hi
          glad it works as expected. I’ve added mine a couple of times for test purposes but I’ve yet to decide where it’s needed. It was quite easy to set up each time though. I live in a semi-tropical country too, and assuming you’re based in Japan, I’m not that far from you, in Taiwan 😉

  • 30th January 2020 at 12:40 am
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    You can make it work with SmartThings and Hubitat as well. Not sure on the raw output from them though, as I’ve not been able to find a data sheet in English that explains the values given. They’re certainly not lux numbers.

    • 30th January 2020 at 1:15 am
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      Thanks, it’s good to know it’s working with other Zigbee hubs. I guess this is due to it being officially Zigbee certified.

      • 30th January 2020 at 1:23 am
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        Yes, the newer stuff seems to be properly compliant this time round unlike the HA 1.2 stuff that wasn’t fully compliant( but usually worked). Not an awful lot of info out there at the moment on the newer sensors like this one. Hopefully an English data sheet will appear at some point that will explain their output values.

        • 30th January 2020 at 1:25 am
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          I know that the new Aqara/Opple wireless switches can be added to the Hue Bridge, but you can’t see it as a device and the buttons are mapped out automatically for you.

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