I build this project so I could setup my camera to take pictures of water drops.
This was built on a Arduino and then transferred to a veroboard.
The circuit uses a laser diode with a LM317 setup as a current limiter. A LDR is connected to the Arduino’s analogue pin and triggers the camera shutter when the laser shining on the LDR is triggered.
The trigger allows you to set the delay time for the trigger by means of 2 switches and the delay is displayed on 2 x 7 Segment Displays (driven by 2 x 74HC595 shift registers)
Check out my blog for the complete project and source code.