Here is an ultra simple Arduino Night Alarm project wired around a handful of inexpensive and easily available components. One advantage of using Arduino as a security system is the flexibility!

This shield includes connections to an alarm system, a GSM modem, temperature and humidity sensors, an Ethernet module, and IR movement sensors. This Arduino Mega attaches to a control box mounted ...

You'll need an Arduino along with a bunch of various sensors to get the project rolling, and once it's all set up you'll have a simple, but cheap system to monitor your home. Head over to ...

All you need is an Arduino, a motion sensor, a few wires and headers, and the code provided at the site below. Hit the link to see step-by-step instructions on how to put it together.