A very useful function of my home automation system is that there's a little light inside my house, on a light switch, that tells me whether or not my garage door is open. This is useful because the light is on the second floor and the garage door is on the ground floor, and not having to walk down two flights of stairs every night before bed is rather handy. Instructables user Steve Moseley shows you how to make this without having a home automation system. More »