Following the instructable here, I was able to turn an old digital camera into a time lapse camera using an arduino, a relay, and an open source software program called makeAVI (windows). To modify the camera I disassembled the camera cover and removed the button that activates the shutter.
It is difficult to tell from the picture, but pressing the shutter button pushes two copper terminals together sending a signal to the camera to take the picture. I soldered a wire to each of the copper terminals. Touching the free ends of each of these wires together is equivalent to pushing the shutter button to take a picture. The next step was to use a normally open relay (sourced from RadioShack) to control when the shutter was activated.
The wiring diagram included with the relay distills the operation of the relay quite nicely. In laymen terms, proving a 5V signal to the coil closes the switch. If a wire from the shutter is connected to the “COM” and “N.O.” pins on the relay then activating the relay takes a picture. In the picture above the yellow wire is connected from arduino pin 7 to a coil pin on the relay. The green wire connects the other relay coil pin to ground. When the arduino makes pin 7 HIGH, the relay closes and tells the camera to take a picture.
For more detail: Time Lapse Digital Camera using Arduino
