Servo - September 2015

There are two major circuits for the Hand of Fate: the transmitter and receiver. The modules used for these two circuits are shown in Figure 9.

The transmitter is the simpler of the two circuits. In it, there are the following modules: power; microphone; and IR LED. While the pink color-coded input microphone module (i21) accepts either voice or sound/music input, the green color-coded output IR LED module (o7) converts the microphone’s audio into light waves. These light waves are then received and decoded by the pink color-coded light sensor module (i13) that has been switched into “light” mode on the receiver. The complete receiver circuit consists of five modules: power; light sensor; speaker; light wire; and servo.

As previously noted, the light sensor receives the IR LED light waves and converts them into electrical pulses. These pulses are output through the green color-coded speaker module (o22) as sound.

We can further “piggyback” on these pulses with the green color-coded light wire output module (o16) and the similarly green color-coded servo module (o11).

In the case of the light wire module, we can wrap the electroluminescent (EL) wire around the candy dish for a pulsing green/blue glow. Likewise, the servo module uses its “turn” mode for moving with the pulses.

You will need a couple of extra supplies like those in Figure 10 for completing the Hand of Fate project. A latex glove (or any other flexible glove) and a craft stick (or a piece of your finest home plastic cutlery, like a “spork”). Attach the craft stick to the screw hub of the servo module. Insert the stick assembly into a finger of choice in the glove. Now, lay the glove on the candy, wrap the candy dish with the EL wire, and secretly hide the entire receiver circuit beside the candy dish.

Carefully align the IR LED from the transmitter circuit with the light sensor of the receiver. In a darkened room, you should be able to separate the two circuits by a distance of two feet. Now, speak into the microphone and watch the Hand of Fate spring into life with an accompanying sound and light show (Figure 11). TIP: It helps to speak very closely to the microphone!

That’s it. Your Halloween is ready for ghosts and goblins. Finally, to get you in the goblin mood, here’s a joke for you: What kinds of streets do ghosts live on? Dead ends! SV Figure 11. "Would you like a candy?” asks the Hand of Fate.