I was asked to transform an old device into a connected device, to follow the usage of the device. As the device will be placed in a lot of environments and is battery powered, I chose to use the Sigfox network (see coverage). Sigfox is an IoT network, that began in France but is now available in a lot of countries.
It is based on an ATtiny2313A and the Wisol SFM10R1 on a breakout board (BRKWS01).
You can read the full blog post and get the source code here: https://www.iot-experiments.com/sigfox-sensor-node/