June 4, 2014
You can turn appliances on and off with your laser pointer, all you need is this switch set up using the following parts and a DFRduino Pro Mini. This looks like it involves messing around with mains power which can be dangerous (or lethal) so make sure you know what you are doing and do it safely. There is probably a way to adapt this idea for any project, including battery powered devices.
What use is it? That's a good question. If you have an answer, Tweet it to me at @ProgressTH or send it via Facebook here. One use might be having multiple switches for as many appliances as you'd like to hook up to this sort of set up and using a single controller (your laser pointer) to control them all. Of course this won't involve additional functions on your appliances like raising the volume or turning down the temperature on your air conditioner, but it will let you turn them all on and off at will. Taking the laser activated aspect of this project alone, you could probably do some interesting Arduino-based interactive projects or even games with it.