This utility reads the Xiaomi Mijia bluetooth sensors. The result is printed to standard output to be graphed with munin. It is a simple standalone utility and does not depend on any runtime libraries (although header files in libbluetooth-dev are needed during compiling). It keeps the bluetooth traffic to the minimum, handle lookups are hardcoded.

• LYWSDCGQ/01ZM (thermometer/hygrometer)
• LYWSD02MMC (clock/thermometer/hygrometer)

• Reading temperature and humidity
• Setting clock (for LYWSD02MMC)

Find the address of the device:

$ sudo hcitool lescan
LE Scan ...
11:22:33:44:55:66 MJ\_HT\_V1
11:22:33:44:55:67 LYWSD02

Read the sensors:

$ ./hyg 11:22:33:44:55:66
temp.value 24.9
hum.value 26.6

$ ./hyg -c -t 02\_0042 11:22:33:44:55:67
temp.value 26.5
hum.value 48.0

Cross compiling to run on Synology (ARM)

sudo apt-get install gcc-arm-linux-gnueabi
sudo apt-get install libc6-dev-armel-cross
CC=arm-linux-gnueabi-gcc make