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.


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:


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.