We love home automation projects, and if there's one thing we'd like to control, it's the air conditioner. Hacker Erik shows us how to control an air conditioner with just an Ethernet cable, a relay board and some PHP.
As long as you know how to solder, this hack is remarkably easy — you just need to solder a few wires to the switches on the air conditioner, and then use the relay board as an intermediary between the air-conditioning unit and your computer. Using a couple of PHP scripts, Erik can punch in his desired temperature from his computer and the air conditioner will set itself.
He even uses a couple of cronjobs to make the temperature changes time-based, so it's running cooler when he's home from work. I imagine if you had some mad scripting skills, you could even have it call on a temperature sensor and adjust the air conditioner according to how hot it was inside the house. Hit the link for more information, and let us know your favourite home automation tips in the comments.