The motion sensor switch circuit can automatically turn on a water sprinkler but you can easily use it as a motion sensor light switch or motion activated alarm too. Before beginning the construction ...

The idea behind this compact and economical Vibration Sensor Alarm is very simple. It uses a cheap and cheerful vibration sensor to drive a piezo-sounder. As can be seen in the circuit diagram, it is ...

[Brad] was asked by his Sister to design a motion-based alarm that would help her catch her son sneaking out of the house at night. Obviously this didn’t need to be a long-term installation so he ...