Instructables user [willnue] wanted to build a diy Tweeting alarm system from the ground up, but reconsidered after taking a close look at the scope of such a project. He settled on using an off the shelf security system, taking care of the Twitter interface on his own. He bought a GE 45142 Wireless alarm and promptly disassembled it to see how he might retrieve status messages from the unit.
He figured that monitoring the alarm’s LEDs would make the most sense, so he used a bit of Ethernet cable and wired all of the system’s indicators to his Arduino board. He hooked up an Ethernet shield to the Arduino, then wrapped the pair up in a plastic project box that closely matched the look of the security system. once that was done, he wrote some simple code for the Arduino that monitors each of the alarm system’s six status lights, sending updates to Twitter via the ThingTweet service.
With this system you might not get your status messages in time to foil whoever is carrying off your plasma TV, but at least you will know what to expect once you get home!
If you want to keep tabs on [Will’s] security system to find out the best time to rob him see how things are going, check out his Twitter feed here.