Requirements
First we need to install the bluez bluetooth stack:
$ sudo pacman -S bluez bluez-utils
To be able to switch the bluetooth on and off I use the bluetooth command from tlp:
$ sudo pacman -S tlp
$ sudo bluetooth on
Next we activate the bluetooth service:
$ sudo systemctl daemon-reload
$ sudo systemctl start bluetooth.service
Connecting
$ sudo hcitool dev
Devices:
hci0 F8:16:54:CD:5F:CC
$ sudo hcitool lescan
LE Scan ...
BC:6A:29:C1:A9:3B SHTC1 smart gadget
$ sudo gatttool -b BC:6A:29:C1:A9:3B -I
[BC:6A:29:C1:A9:3B][LE]> connect
Attempting to connect to BC:6A:29:C1:A9:3B
Connection successful
Reading the sensordata
According to the SmartGadget-iOS code The UUID to read the temperature is 0xAA21. So we try to read it:
[BC:6A:29:C1:A9:3B][LE]> char-read-uuid 0xAA21
handle: 0x0025 value: 66 0b b9 14
The first 16-bit value is the temperature and the second the humidity. Note that the byte order of the values is big endian.
So to calculate the measured temperature in python we need to:
>>> temperature = 0x0b66/100.0
>>> print(str(temperature)+ "°C")
29.18°C
>>> humidity = 0x14b9
>>> print(str(humidity)+ "%RH")
53.05%RH