Sometimes you can switch lights without a direct connection to the mains, however – like this project that interfaces mechanically with a standard light switch.

Most of us have an 8x8 LED matrix from one of our Arduino kits. What can we do with them? This module investigates how to use these interesting devices. Along the way, we describe a fun electronics ...

The Arduino uses latitude and longitude to help decide when to click on the lights, so it's incredibly accurate. Otherwise, the build just includes an on/off switch, a Tiny RTC, a time adjustment ...