Ben Brooks has been experimenting with Particle boards, specifically the Photon, leading him to examine what devices around the house might benefit from WiFi functionality. Naturally the doorbell, or doorbells in his case, make great targets. While there are certainly commercial alternatives on the market, he didn’t want to change his existing doorbell setup, in part for a challenge, and in part because he likes the way it looks.
What he did instead was take the signals from the doorbells and pipe it to a Particle via optocoupler. This can then trigger a camera to record visitors/intruders, notify his phone, and blink the smart lights around his house. Each doorbell has its own input on the board, meaning there could be different responses depending on where the signal is coming from.
The notifier was first implemented on a breadboard with a Photon, then transferred to a PCB and a Xenon about a year later. The big challenge of this build, and thus the reason for the optocouplers, is that U.S. doorbells are normally powered by 12VAC, yet his is 20 for some reason. The optocoupler isolates everything nicely, though issues with the AC power input and power fluctuations had to be accommodated for with software. The speed difference between the Photon and the Xenon also had to be taken into account, but the end result is a very nice setup that should serve nicely for home automation purposes! Code and print files are available on GitHub.Go to Source
Author: Jeremy S. Cook