There are lots of tutorials out there about building your own alarm system with x10, Arduino, etc. But what if you have a professional home alarm system already? There are a bunch of sensors all over your house. When a criminal isn’t actually currently breaking your window, all that sensing power is basically going to waste.
Why not tap into it, so you can see when people are home, what rooms you use at different times of day, and other valuable tidbits about your daily life? You could use it to turn off lights or HVAC when you’re not home, or just learn more about your daily routines. Alarm.com evidently had the same idea with their Wellness system, but why not do it yourself?
That’s exactly what Gilberto has done. He provides detailed instructions for connecting a Raspberry Pi to your existing home alarm system, using a Netduino and ATtiny85. You can read all the motion sensors, and even bring in temperature information if your alarm system has it. Gilberto even provides code to have the system send you emails when it detects motion, or upload your data to xively for graphing and analytics.
HomeAlarmPlus Pi is a complex build, but Gilberto walks you through all the details of his setup with some nice circuit diagrams and pictures. You’ll probably have to modify it to work with your particular alarm system.
If you want to follow along with his instructions, I’ve made it easier for you by linking to sources for much of his parts list below. The unlinked items are basic components you can get from Radioshack, Sparkfun or Digikey.