Servo - September 2016

This year marked the 11th time that I have gone to Maker Faire in the Bay area of California. About one month before this year’s event, I didn’t have anything built and I was supposed to share a booth with my friends, Bill and Becky Sherman and their robots. Fortunately, the solution had been staring at me from across the living room for a few years. It was Pete and Tony (The Talking Heads).

These two “guys” were initially going to be used as part of another project with my BarBot, Brandy’s Bar. They were intended to be buddies talking and telling random stories and jokes at the bar. Unfortunately, I ran out of time during that build, so they have been sitting here staring at me and waiting.

I got to digging through some other past projects and found a servo motivated skeleton (Cal Averas) and an LED color organ. Once I had all of these components laying in a pile on my living room floor, I thought to myself, “I’m going to talk to these guys and they will talk back to me, just like in the movies. Oh boy, this should be easy!” Yeah, right. I should know better by now.

Getting My Act Together

The first task was to untangle all of the wiring that powers and controls the LEDs that cause the eyes and mouths to blink in the plastic skulls that are Pete and Tony. That took awhile since I forgot how they worked and if they ran on 5 VDC or 12 VDC. I took Pete’s head apart and found some half watt 680 ohm resistors connected to the anodes of his LEDs, so I knew they would run safely at 12 VDC. Each head has green, blue, and red LEDs that illuminate the mouth and the opaque teeth, and two red LEDs that illuminate the eyes.

To keep it simple, I just tied the cathode wiring all together so everything would flash at once. After Pete was tested, I did the same modification to Tony. (Cool, now I have two heads with blinky lights!) Now, I needed to control their lights. To get the lights blinking, I added an LED color organ that I had built from a schematic from an article. A color organ takes line level audio, and by using low pass filter circuits, can break down the various sound frequencies depending on which frequencies each circuit is tuned to.

Something that you always see in the movies are robots that can both listen and talk to humans and other critters using flawless voice recognition and artificial speech. Of course, this technology does actually exist, but is it perfect? Well, not exactly.