Wouldn’t it be cool to have an alarm sound each time someone opened your door, lunch box, or secret drawer? It’s easy when you use a reed switch in your circuit! All you need to do it substitute this sensor for the trip wire and you’ll have a magnetic burglar alarm.
The first thing you need to do is get your reed switch out, because we have to tear into it in order to get the part we need. Here’s what you need:
Materials:
- reed switch
- magnet
- LED
- AA case
- 2 alligator wires
- 2 AA batteries