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 ...

this DIY motion trigger for a DSLR is a quick and easy build, and probably loads more fun. The BOM on [Jeremy S Cook]’s build is extremely short – just a PIR sensor and an optoisolator ...