He’s using an Arduino Uno and an Ethernet breakout board to hook it up to the network. This allows him to send text messages to himself when the alarm system is armed, disarmed, or triggered.

[IngGaro]’s latest project uses the full range of features available in this versatile microcontroller and has turned an Arduino Mega into a fully-functional home alarm system.

Now it is very easy to build your own siren sound alarm, small enough to be carried in a garment pocket. This powerful audio-visual alert device is realized using the renowned Arduino platform. The 9V ...

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!

Alarm clocks are cheap and abundant, but they’re pretty boring. If you want to make your own, Instructables user Paranoid Legend shows you how to build one with an Arduino.

Full instructions on how to create your very own Arduino music player and alarm clock have been kindly published by Dejan Nedelkovski with all the code you require.

However, if you’re just looking to catch a sandwich thief at work or a cat spilling over all you water bottles, then Make shows you how to build an alarm system with an Arduino and a USB camera.