Xiaomi BLE Temperature and Humidity sensor


The mitemp_bt sensor platform allows one to monitor room temperature and humidity. The Xiaomi Mijia BLE Temperature and Humidity sensor with LCD is a small Bluetooth Low Energy device that monitors the room temperature and humidity. As only a single BLE device can be polled at the same time, the library employs locking to make sure this is the case.

Installation

Depending on the operating system you’re running, you have to configure the proper Bluetooth backend on your system:

  • On Hass.io: mitemp_bt will work out of the box.
  • On a generic Docker installation: Works out of the box with --net=host and properly configured Bluetooth on the host.
  • On other Linux systems:
    • Preferred solution: Install the bluepy and btlewrap library (via pip). When using a virtual environment, make sure to use install the library in the right one.    - Fallback solution: Install btlewrap library (via pip) and gatttool via your package manager. Depending on the distribution, the package name might be: bluez, bluetooth, bluez-deprecated
  • Windows and MacOS are currently not supported by the btlewrap library.

Configuration

Start a scan to determine the MAC addresses of the sensor:

$ sudo hcitool lescan
LE Scan ...
4C:65:A8:D2:31:7F MJ_HT_V1
[...]

Or if your distribution is using bluetoothctl:

$ bluetoothctl
[bluetooth]# scan on
Discovery started
[CHG] Controller XX:XX:XX:XX:XX:XX Discovering: yes
[NEW] Device 4C:65:A8:D2:31:7F MJ_HT_V1

Check for MJ_HT_V1 or similar entries, those are your sensor.

To use your Mi Temperature and Humidity sensor in your installation, add the following to your configuration.yaml file:

# Example configuration.yaml entry
sensor:
  - platform: mitemp_bt
    mac: 'xx:xx:xx:xx:xx:xx'
    monitored_conditions:
      - temperature
  • mac (Required): The MAC address of your sensor.
  • monitored_conditions array (Optional): The parameters that should be monitored (defaults to monitoring all parameters).
    • temperature: Temperature in C at the sensor’s location.
    • humidity: Humidity level in % at the sensor’s location.
    • battery: Battery details (in %).
  • name (Optional): The name displayed in the frontend.
  • force_update (Optional): Sends update events even if the value hasn’t changed.
  • median (Optional): Sometimes the sensor measurements show spikes. Using this parameter, the poller will report the median of the last 3 (you can also use larger values) measurements. This filters out single spikes. Median: 5 will also filter double spikes. If you never have problems with spikes, median: 1 will work fine.
  • timeout (Optional): Define the timeout value in seconds when polling (defaults to 10 if not defined)
  • retries (Optional): Define the number of retries when polling (defaults to 2 if not defined)
  • cache_value (Optional): Define cache expiration value in seconds (defaults to 300 if not defined)
  • adapter (Optional): Define the Bluetooth adapter to use (defaults to hci0). Run hciconfig to get a list of available adapters.

Note that by default the sensor is only polled once every 5 minutes. This means with the median: 3 setting will take as least 15 minutes before the sensor will report a value after a Home Assistant restart. Even though the hardware is able to provide new values every second, room temperatures don’t change that quickly. Reducing polling intervals will have a negative effect on the battery life.

A full configuration example could look like the one below:

# Example configuration.yaml entry
sensor:
  - platform: mitemp_bt
    mac: 'xx:xx:xx:xx:xx:xx'
    name: Kids Room Temp
    force_update: false
    median: 3
    monitored_conditions:
      - temperature
      - humidity
      - battery