Color-Changing Doorbell

Home Technology
Color-Changing Doorbell

Spotted in the MAKE Flickr pool, from Engineer Eiki Martinson of Lighthouse Point, FL. He writes:

This uses an Atmel Attiny12 to drive a single 5mm, 4-lead RGB LED embedded in the doorbell switch (I drilled into it to remove the original incandescent bulb). Power is taken parasitically from the doorbell transformer (16 VAC, if I remember correctly) in the attic of the house somewhere, and the switch shorts the whole thing, ringing the bell and resetting the microcontroller. The color cycle starts with pure white upon reset, providing a visual indication the ring has occurred.

Just in time for Halloween! Nice work, Eiki!


I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and My work has also appeared in ReadyMade, c't – Magazin für Computertechnik, and The Wall Street Journal.

View more articles by Sean Michael Ragan
Send this to a friend