Trandi posted a step by step guide of his DIY wireless doorbell build:
So this was the perfect pretext for a small electronics project, centred around the idea of a simple voltmeter that would notify us when the voltage goes below a safe level. This would most easily be done with a small micro controller that has an ADC.
For some reason I quickly decided that I also wanted the doorbell to count the rings, to be able to quickly see if we’ve missed anybody while away from home.
Check out the video after the break.