- Xiaomi MiJia 'Bluetooth Hygrometer' LYWSDCGQ are hygrometers
- Has sensors to relay temperature and humidity
- Uses Bluetooth Low Energy (BLE) and has a limited range
- An AAA battery is used as power source
- Read real-time sensor values
- Read historical sensor values
- Temperature and humidity sensors
The device uses BLE GATT for communication.
Sensor values are immediately available for reading.
The basic technologies behind the sensors communication are Bluetooth Low Energy (BLE) and GATT. They allow the devices and the app to share data in a defined manner and define the way you can discover the devices and their services. In general you have to know about services and characteristics to talk to a BLE device.
Bluetooth payload data typically uses little-endian byte order.
This means that the data is represented with the least significant byte first.
To understand multi-byte integer representation, you can read the endianness Wikipedia page.
The name advertised by the devices is MJ_HT_V1.
TODO
TODO
There seems to be two kind of advertisement data broadcasted.
LYWSDCGQ broadcast service data with 16 bits service UUID 0xFE95 and 0xFFFF.
Check out the MiBeacon protocol page to get more information on advertisement data for this device.
| Position | 00 | 01 | 02 | 03 | 04 | 05 |
|---|---|---|---|---|---|---|
| Value | e7 | b9 | f8 | 86 | 54 | 48 |
| Bytes | Type | Value | Description |
|---|---|---|---|
| 00-05 | bytes | ? |
[1] sputnikdev/eclipse-smarthome-bluetooth-binding#18
MIT