• expired

2020 Xiaomi Bluetooth Temperature Humidity Sensor, 4 pack US$17.86 / A$27.30 Delivered @ MIJIA-GLOBAL Store Aliexpress


Use citibank or maquerie card to avoid extra fees and best conversion rates. A few cents less if you have collected AliExpress Coins.

Custom Firmware: https://github.com/pvvx/ATC_MiThermometer

This is a household temperature and humidity sensor, not industrial grade, so the temperature will have an error of ± 0.5 °; There will be an error of ± 2% in humidity, which is normal.

  1. Home hygrometer, data can be clearly read in various brightness and angle.
  2. High sensitivity and accurate sensirion from Switzerland, sense subtle change of temperature and humidity a breath away.
  3. An expression to spell over comfort level, cute and simple.
  4. Low consumption screen, a CR2032 button battery for one-year.
  5. Built-in advanced Sensirion temperature and humidity sensor, temperature accuracy: 0.1 degrees, humidity accuracy: 0.1 percent RH

  6. Via Mi app to switch on humidifier when indoor humidity is too low and air-conditioner when indoors temperature is too high
    LED digital display, you can get temperature, humidity easily

Package included:

1 x Xiaomi Mijia Thermometer Hygrometer
1 x Wall Sticker
1 x Use Manual(Chinese)

Related Stores


closed Comments

  • +1

    Anybody know how to make these work in Home Assistant? I also don't have a Bluetooth coordinator which I am not sure to get actually

    • +4

      Flash via the GitHub link and then simply add via the BThome integration. I use a laptop and run via a Virtual Box VM and it works fine in conjunction with my other BT devices

      • My Dell Optiplex doesn't have a Bluetooth built-in, what do you recommend in terms of Bluetooth coordinator for HA?

          • @bdl: Would the short range of Bluetooth be an issue if you're placing these sensors ~15m (with a couple of walls between) away from your PC running HA?

            • +1

              @tikeyike: These units have a BT5 receiver and function 20m from a raspberry pi for me. Minimal battery consumption too. The bluetooth is the best part of these units.

            • +1

              @tikeyike: Test in your environment and see. You can also grab one of these https://vi.aliexpress.com/item/32864722159.html (ESP32-D CH9102 model) and install this on it - https://esphome.github.io/bluetooth-proxies/ - and you can place the receiver wherever you want :) [you won't need the USB dongle in this case]

              • @bdl: Cheers for that, I'll look into it 👍

            • +1

              @tikeyike: Nope as long as you use the custom firmware and configure the signal transmission power to be more than stock. Mine to through multiple brick walls and floors. One of the key reasons to use custom vs Xiaomi firmware. Both work with home assistant

              • @10101010101: I ended up purchasing 8 sensors along with a Bluetooth adapter. I'm keen to see how they perform, and with any luck, I won't have to set up a Bluetooth proxy device.

                The main goal of this setup is to enhance the built-in AC temp sensors. Currently, my AC only has two temperature sensors - one downstairs and one upstairs. The issue is that it averages the warmer temperature upstairs with the colder temperature downstairs, leading to less accurate temp readings.

                Another idea I had is to place one sensor outside to gather the outdoor temperature. I can then use this information to optimise the indoor temperature. For example, I'm considering adjusting the indoor temperature to be around + or - 8 degrees of the outside temperature (I just picked 8 degrees as an example).

        • I've flashed these via chrome on android.

      • Can you tell me how to get started with home assistant. I always read about people having awesome setups on these threads and I get jealous

        • +1

          Basically you just need some sort of computer e.g. an old laptop, that basically needs to be on 24/7. Install HA by going here. Pick your OS, and follow the installation instructions. Fiddle around with your network settings, so you can access HA on other devices on your network. Once you have HA up and running, then assuming you have your smart home devices already on your network, you HA can magically "discover" most of them (since they are already on your network). Follow the onboarding guide here for the rest.

        • After thinking about it too much, I picked up a Dell Optiplex from marketplace for cheap, installed proxmox as I wanted to install more servers eventually, and installed HA to kick it off. My main goal was to have a cheap alarm system for home, everything else was a bonus. My sirens are Google Hime devices. Most of my sensors are ZigBee from Ali. My coordinator is a Sonoff Dongle. Let me know if you have any other questions haha

        • Dive in and play around. And then after you're a bit more comfortable with it you may end up rebuilding and starting again. I started with a RaspberryPi but the SD card died and I started again with a GIGABYTE BRIX that I had lying around.

      • +1

        Flash, GitHub, BThome integration, Virtual Box VM

        Wow…. Those words scare the hell out of me…. Sorry noob here

        • I'm running HA in a docker container on a dedicated Ubuntu server, saving my yaml code to the nas but thinking about setting up a cluster which according to google "is a dynamic system that places and manages containers, grouped together in pods, running on nodes, along with all the interconnections and communication channels". Does any of that help at all? ;-)

    • run esphome server inside docker / homeassistant extensions, buy a few esp32's to put around the house to use as "Bluetooth proxies", as soon as the esps are setup as a proxy all ble devices should be discoverable by homeassistant :)


      edit: seems like this custom fw advises against using esp32's as ble proxies. should work fine for other devices though :/

      • They work perfectly, I have three :) The sensors in the OP don't hold open an active connection so they are fine. Also pick up my neighbour's BT oral b toothbrushes too :|

        I'm also using the same model ESP32-D with a Powerpal

    • I have my Airthings Wave Mini work with my HA over BLE without Bluetooth coordinator.

  • US$17.86 (~AU$26.20) inc GST.

  • Have these and they are not accurate at all. Side by side, humidity level is off by 3-4

    • Pretty sure you can calibrating them using the pvvx custom firmware

    • What about temperature?

      • +1

        Temp difference is about 0.5 degree C more or less

    • None of the cheap humidity sensors are very accurate, but it doesn't really matter. You're not gathering weather data, you're just using it as an indication.
      Anywhere between 5-10% is acceptable most of the time

      • not when you're trying to keep humidity at a certain level and the gauge you purchase gives incorrect info. Either you keep the dehumidifer running a little too long or turn it off too early matters to some.

  • What you guys use these for?

    • +3

      Temperature and humidity usually. And testing CR2032s

      • Not great for testing CR2032s as they still work in other devices like kitchen scales after they stop working in these.

        • I found the other way around, these thermometers run them dry (but I'm on the pvvx firmware)

      • My new CR2032 batteries I had lying around didn't work with these. Is there special CR2032 batteries that are needed to run these?

        • What brand are your batteries. While cheap no name batteries work, some don't last long

        • Just standard ones

    • +1

      Each of my bedrooms have one. Paired with Home Assistant and Wifi AC I can set target temperature, which is more accurate and reliable than setting the temp on the AC itself.

  • I can't see anything about the error factor. I've been looking at similar devices and they often have an error of +/- 1 degree C, which in my opinion is useless. I could probably guess the temp just as accurately.

    • Useless? They are handy to have scattered around the home as a good guide to room Temps. Even if they were out by say 1c, you can always factor that in.

      Regardless, assuming you have x4, place them all together to check if they all show the same Temp and calibrate them so that they do. You do however need another device that is 100% accurate to calibrate against.

  • added on GST 10%

  • If your just looking for a convenient display and don't need the bluetooth part, you can get a 4 pack of these for ~$5 from aliexpress

  • I use the zigbee version of these - I have them in my bathroom/ensuite and i have an automation that turns on the extractor fan when the humidity goes up by a variable percent in a minute and turns off when humidity drops back down - works really well and reliable

Login or Join to leave a comment