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Thrilleratplay / GoveeWatcher

Proof of concept bluetooth broadcast decoder from Govee Thermometer/Hygrometers
MIT License
63 stars 14 forks source link
bluetooth-low-energy govee h5051 h5072 h5074 h5075 h5101 h5102 h5177 h5179

readme

Govee Watcher

This is deprecated.

The work done here was continued as a Home Assistant Component and ble_monitor

Multiple Govee device Thermometer Hygrometer

Orinignal proof of concept Bluetooth broadcast decoder from Govee H5075 Thermometer Hygrometer Versions:

How does it work

The Govee H5075 Thermometer Hygrometer broadcasts the current temperature and humidity through Bluetooth low energy (BLE) advertisement data.

Packets

From the socket data provided by python-bleason debug logging and advlib's decoding information

Base

Octets Value if static Description
1-3 Header?
4 - 9 ZZ YY XX 38 c1 a4 MAC Address in reverse order. Example a4:c1:38:XX:YY:ZZ
10 1f ?
11 0d Length of local name
12 09 Complete Local Name
13 - 20 47 56 48 35 30 37 35 5f First part of device name "GVH5075_"
21 - 24 Last four hex values (last two octets) of the MAC address spell out in ASCII.

Example of temperature/humidity advertisement

Octets Value if static Description
25 03 Length of payload
26 03 flag for "Complete List of 16-bit UUIDs"
27 -28 88 ec Manufacturer Key
29 -31 02 01 05 GAP list of 32-bit UUIDs but it is empty(?)
32 Length of payload. For this instance it is 09
33 ff Manufacture data flag
34 -35 88 ec Manufacturer Key
36 00 padding?
37 - 39 Encoded temperature and humidity
40 Battery remaining percentage
41 00 padding ?

Decoding Data

The three octets are concatenated together and parsed into an integer Example: 03 21 5d -> 03215d --parse integer--> 205149

For positive temperature values (above 0°C/32°F):

Once we have this integer, for the temperature in Celsius, divide by 10000

205149 / 10000 = 20.5149°C

Humidity is modulus 1000 divided by 10

205149 % 1000 = 149
149 / 10 = 14.9% humidity

For negative temperature values (below 0°C/32°F):

See issue #2

Received Signal Strength Indicator (RSSI)

There is a second advertisement signal contains the ManufacturerData Key 0x004c and payload data INTELLI_ROCKS, (Govee is the brand name, the manufacture is "Shenzhen Intellirocks Tech. Co., Ltd."). Based on the finding in neilsheps/GoveeTemperatureAndHumidity, this relevant to the Apple iOS application. This however provides the RSSI for the device.

Historical data?

This is only a proof of concept for decoding BLE advertisements and do not plan on continuing on to load historical data. Thes are done through commands sent to GATT services.

Additional data