Remote Tripwire Alarm

A tripwire is one of the most basic ways to set up a simple security system. You run a line across a pathway. Then when someone walks through the line, it activates an alarm. This kind of system is easy to set up and is fairly effective. But there is always room for improvement.

The most inconvenient thing about a classic tripwire alarm is that it requires you to run a physical line from the tripwire to the alarm. This makes it difficult to set up a system where the alarm is far away or inside a building. To get around this problem, I designed a simple remote alarm system that uses a small radio transmitter to activate the alarm wirelessly. So in this project, I am going to show you how to make a simple remote tripwire alarm.

Instructable: http://www.instructables.com/id/Remote-Tripwire-Alarm/