In my current flat the central heating runs on natural gas and I wanted to have a nice chart showing its consumption. The gas meter is directly in the hallway so everyone can see it. Because of this, I cannot simply bring in AC power and attach some exposed wires, otherwise my neighbors would probably call anti-terrorist group. The measuring device has to be small, look professional and have low power consumption so it can run on batteries. In next lines I’ll describe how I have achieved this.
As I promised last time, I’m going to continue with st-link programmer clones. This time I wanted to use mbed which has some ready made libraries for utilizing USB and since it was very comfortable to use DFU upload with arduino library, at first I checked if it is usable with mbed too.