blelt2mqtt : Bluetooth LE LT Thermometer 2 MQTT

This software is a simple gateway to publish on MQTT for use with Home Assistant or Domoticz temperature data from cheap bluetooth sensor LT Thermometer

Supported devices

Device	Photo	Where to find (examples)
LT Thermometer v3		AliExpress

These devices are supported by an android application named "qaqa" which is available here : https://d.ihunuo.com/app/dqwu (LT-Thermometer v3.apk)

Install

Prerequisites:

• Linux, Windows or MacOS (only tested on Linux / Raspberry)
• Bluetooth LE compatible device (with installed stack)
• Python3 with pip3

Installation steps:

1. Install needed Python modules (bleak, paho-mqtt)

pip3 install -r requirements.txt

2. Configure your sensor anq MQTT server in the configuration file

3. To ensure the software is launched at startup :

crontab -e

@reboot bash /path/to/blelt.sh

Configure Domoticz / Home Assistant

This should not require extra configuration for use with MQTT auto-discovery.

If you want to have a domoticz sensor with temperature and humidity, you need to follow these steps:

1. Configure a virtual sensor Temperature+Humidity through the Dummy hardware in Hardware menu
2. Read the idx of the created device in the Devices menu
3. Add the idx in the configuration file as 'domoticz_idx'

You should now see the sensor (native sensor on the left, auto-discovered on the right) :

Protocol

The reverse-engineered protocol is described in protocol.md and the process is described in this article (in french)

Useful links

• LT-Thermometer v3 Android or iOS application
• Bluetooth UUID Nordic open database and official 16-bits list (spoiler: the used UUID aren't in there...)
• BLE Tutorial for Arduino
• Home Assistant auto-discovery protocol and fields definition for sensors
• Domoticz auto-discovery support with native client or plugin
• Domoticz MQTT sensor messages format

License & Credits

GPL

2022 - Remi Peyronnet