Many alarm projects are rather simplistic: a single sensor protects a single object or field of view. Such projects are good for learning or practicing simple circuit techniques. But eventually you may wish to have a more advanced / sophisticated alarm system. More like those used by commercial alarm companies. Actually the circuits needed to accomplish this are still fairly simple and can be built around the Adafruit Trinket mini microcontroller.

This tutorial will provide you with:

• The basics of how alarm systems are function
• Alarm system design
• Building a practical alarm
  
• The code
• Installation and use
• Bluetooth wireless information transmission
• How to add additional capability

This project was demonstrated on Adafruit's Show and Tell on December 7, 2013

https://www.youtube.com/watch?v=yw5I9pKP2Uo