3.2. Instructions

3.2.1. Assemble Prototyping Shield

Control connections to the camera are made using a pair of reed relays that provide complete electrical isolation between your Arduino and the camera itself. In fact, this project has been designed to use the same pins as the first two outputs on the relay board used in the very first project, Appliance Remote Control, so that if you've already built that project, you can use the same board without modification. That's exactly what we did, and the only difference is that rather than wiring the 3.5mm stereo socket directly to the relay outputs, we needed to connect it to a pair of headers to plug into the relay outputs. If you're building a shield specifically for this project you can start by following the instructions for the Appliance Remote Control project in Chapter 2, but only fit the first two relays that are connected to Arduino digital I/O lines 5 and 6 along with their matching reverse-biased diodes.

Then wire up the 3.5mm stereo socket so that the outer (shield) connection goes to one terminal on both relays, the center (ring) connection for the focus trigger goes to the other terminal of the relay on digital pin 5, and the tip connection for the shutter trigger goes to the other terminal of the relay on digital pin 6.