Coding4Fun

Building the Hardware

The hardware is based around the Phidget Interface Kit 0/0/4. This board contains four relay outputs that can switch (turn on or off at will) an AC or DC current. The instructions here will be for building a single unit light, which will drive four channels of lights, but you can build as many units as you'd like and use them all at once to create larger light shows.

Using the Interface Kit, we will build a device that can be plugged into a single AC outlet and will provide four output outlets that can be switched on and off by the Interface Kit's relays. With the light strings plugged into these four outlets, they can be turned on and off at will. The software that accompanies this chapter will allow you to build a "sequence" that will turn the lights on and off at specified times, usually in time to the music, creating an animated light show.

To start, we will prepare the extension cords. First, cut the female end (that's the one with the holes, not the plug) off of a single extension cord. Next, split the cord up the center about 2 inches. Strip a bit of insulation off of each wire to expose the ends, and then twist the ends with your fingers to create a neat, twisted wire, as shown in Figure 10-1. It is best to strip the wires using a pair of cutting pliers, which you can pick up at a local hardware store if you don't already have a set. Using a knife or scissors may work, but it will be a lot more difficult.

Figure 10-1. Prepared female-ended extension cord ...