“A system to trigger a Canon DSLR camera when there is motion in front of it. Uses a PIR, opto-isolator, and not much else!
If you have a Canon DSLR (may work with others—I’ve tested it with a T2i) that you’d like to set up to observe nature and other phenomena that moves, this device will help you do just that. It uses a passive infrared (PIR) sensor—described here among other microcontroller sensing options—to detect motion, then an opto-isolator to connect the ground and trigger pins. No other active components are needed!”