This motion detector alarm can detect a moving person from a distance of 1 meter. It uses a dual IR Transmitter-Receiver module HOA1405. When the sensor detects the reflected IR rays, alarm will sound ...

Let me introduce another simple microcontroller-based do-it-yourself circuit that detects motion and excites a light source in a flash. The “snooper” here is an ordinary passive infrared (PIR) motion ...

[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 ...

We’re still not sure exactly how [connornishijima]’s motion detector works, though many readers offered plausible explanations in the comments the last time we covered it. It works well enough, though ...