In this project I will show you how to build a very simple security system for all kinds of rooms. It might be simple but still effective. It is based around an Attiny85 and uses a reed switch and a key switch as inputs to see whether an intruder has accessed the room. A buzzer will then notify you or other persons. Let's build it
The video gives you all information to build this simple security system. But I will cover the most important steps again.