CPUTemp

Python GATT server example for the Raspberry Pi

Copyright (c) 2019, Douglas Otwell

Distributed under the MIT license http://opensource.org/licenses/MIT

Prerequisites

As of BlueZ version 5.43 (currently shipped with Raspbian Stretch), some BLE aspects are still experimental. You will need to add the 'Experimental' flag to the bluetooth daemon. Do this: sudo nano /etc/systemd/system/dbus-org.bluez.service and add the '-E' flag at the end of the 'ExecStart' line. It should look like this:

ExecStart=/usr/lib/bluetooth/bluetoothd -E

Save the file and reboot.

Installation

git clone https://github.com/douglas6/cputemp.git
cd cputemp

Usage

python3 cputemp.py

The server should by accessable by any BLE client; I like to use the 'nRF Connect' app on my Android phone.

The service (UUID 00000001-710e-4a5b-8d75-3e5b444b3c3f) provides two characteristics:

UUID 00000002-710e-4a5b-8d75-3e5b444b3c3f: a read/notify characteristic representing the Pi's CPU temperature as a string.

UUID 00000003-710e-4a5b-8d75-3e5b444b3c3f: a read/write characteristic indicating the units to use to display the temperature; 'F' or 'C'.