Adding onto an existing home alarm system (ADT)

My fiancee and I recently purchased a new home with a detached garage and had ADT come install a security system in the house but were told they would not install a system in the garage that would work in the hot/cold weather as the garage is not climate controlled. They cited numerous issues with motion sensors and other factors such as humidity.

They did offer a commercially available option that costed hundreds of dollars and required a trench to the garage.

So… i decide to make my own security system for the garage and tie it into my ADT alarms system using the following:

2x Arduino Uno
3x xbee series 2
1x Parallax PING (sonic range finder)
2x PIR (motion detection)
1x Photoresistor
1x Temperature / Humidity Sensor

Using the above i created a small sketch that would sample the sensors and transmit the data as well as transmit ‘Events’ or stateful changes detected on certain sensors such as

  1. Change in distance - The PING sensor was using to ensure that my Snowblower was still in the garage but can easily be used to ensure other items state put.
  2. Motion - the two motion sensors are using to create two zones which cover the two entry points as well as the bulk of the open space in the garage

The second arduino and xbee are used to trip what is essentially a basic continuity sensor that most ‘window’ alarms provided by ADT leverage. So now instead of paying them $50+ USD for additional motion sensors you can use a generic PIR for ~$10 and tie it in. The only downside is that to ADT it will always apear to be the same zone.

Lastly i built a small java app which runs on my QNAP nas and listens for the sensor data and generates email notifications with the below image in it when something relevant happens. My plan is to expand this java app into a more full blown web based home automation and monitoring solution include ties into my HVAC system.