Adam Romanowicz was looking for a simple way to quickly trigger his Canon camera when photographing lightning strikes, and developed a simple and easy to build camera trigger. Using an Arduino, some simple circuitry and a hacked external shutter release cable, the results work very well. For example:
To save processing time the Arduino sketch uses direct port mapping instead of the digitalWrite function, so if you're using an Arduino-style board that uses a different microcontroller to the ATmega168 or -328, be sure to check the code before use. For more information, including the code and circuit, visit Adam's site here. To get started with your own camera trigger, consider using the Freetronics Eleven - the Arduino Uno-compatible with onboard prototyping space:
