Alarm systems are complicated affairs. 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 ...

Here is a simple general-purpose security alarm circuit built on the Arduino platform. It brings up an obtrusive alert signal when an intrusion/theft attempt is observed by its front-end sensor. In ...

I just received my RC522 RFID reader and made this simple Arduino access control system that uses the reader, a buzzer for the alarm and a relay shield for the security system. The relay can be used ...