Build a Timed Burglar Alarm

Science Fair Project Information
Subject: Electronics
Grade level: High / Middle School - Grades 7-12
Academic Level: Ordinary
Project Type: Building Type
Cost: Low
Awards: None
Affiliation: http://www.electronic-circuits-diagrams.com
Description: This alarm circuit has a 555 timer, so the alarm will reset its self after a certain amount of time that you select. The time is adjustable with a variable resistor in the circuit. The alarm uses a relay which is connected to a siren. The circuit is running on 9V but can range from 4V - 16V.
Link: http://www.electronic-circuits-diagrams.com/alarmsimages/alarmsckt20.shtml