Teardown: Mi Thermometer/humidity sensor

Many people know Xiaomi for their smartphones. They are becoming more and more popular also in Europe. However, in their home market in China they sell also smarthome components. As many of these systems they use a central hub that connects to and controls sensors and actuators. One sensor that I personally found very interesting is the Mi temperature/humidity sensor. With it’s diameter of only 36mm, you can install it almost everywhere.

One thing, you will notice is that the build quality is very good. The case is plastics, but still feels very well made.

Is this sensor locked to the Xiaomi smart hub or can you use it also in DIY environments? Let’s open it and see how it works.

P7260896

The device is powered by a small CR2032 cell. Let’s hope this one lasts at least a year. But let’s check the main board which will tell us more about how this thing works:

mi-therm-board

It also looks very well-designed and assembled. The main processor is a JN5169 from NXP. It is a Zigbee controller. Do you remember Zigbee? While today most new designs use Bluetooth LE, Zigbee is still there. And it works quite well, so why not use it. The only thing that makes it a bit harder to use is the fact that no PC comes with an integrated Zigbee interface. That means you need to have an additional Zigbee controller connected to your PC, Raspberry Pi or Arduino to read data from this sensor. Is it easy to integrate? We don’t know yet, but we will look into this in the future.

16 thoughts on “Teardown: Mi Thermometer/humidity sensor”

  1. Hi man! Awesome blog you have running here, thanks a lot for publishing (and providing information). Any news on the hackability of the Mi Thermometer and/or integration with HASS? 🙂

    1. I don’t know if the protocol has been reverse engineered yet. Therefore I can’t say if and how you can use it from the Raspberry Pi.

  2. Any news/success/failures on integration? Are these crazy cheap and seemingly well built line of sensors able to integrate with a custom zigbee controller connected to, say, a raspberry pi?

  3. Ich bin sehr an der Fortsetzung dieses Arktikels interessiert! Welche Erfahrungen wurden gemacht in Bezug auf Betrieb ohne Xiaomi Gateway?

  4. Wenn Du mal wieder Zeit hast, schau Dir das doch einmal an.
    Ich bin totaler Laie, fände es aber großartig, wenn man diese Teile einbinden könnte.

  5. I have one of these, and use a raspbee interface from Dresden. It comes with some software called deConz that can talk to this thermometer and exports all the data via a rest interface or websockets for real time push.

    I’m using it all with Home Assistant (HASS) and its working perfectly.

  6. There is a small pocket close to the bottom you pillow on one of the sides. To remove the cover, simply slip the end off and work the cover around. You will use the same procedure to put it back. Consider reading the user manual for more information on how to best use the pillow.

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