Photo of Dangerbot (side view)
Dangerbot (side view)

Here is Dangerbot 1. He is the first Fred Head that I built. The base is a lid from a prescription bottle and the ribbed stuff wrapped around it is part of an old printer drive belt. You'll notice I repeated this decoration on the plastic bubble above the motor as well.
Photo of Dangerbot's belt drive and underside
Dangerbot's Belt Drive

Photo of Dangerbot (front view)
Dangerbot (front view)

I've noticed that the fred head circuit is sometimes prone to random movement. He will turn away from light and eventually be facing away from the source of light. Upon further investigation, I found the reason to be that the red LED's used have a kind of magnifying lens end on them (like most LED's do) which focuses the light inside the LED. This effect makes Dangerbot predictable only if the light is in nearly a direct line with the LED. Since I designed Dangerbot to be a desk ornament of sorts, this was OK.

When I made a Dangerbot for my brother, I also made up a complete and detailed instruction booklet which is available HERE as a PDF. If you're considering building a FRED Head style robot, this is a must read guide with lots of good information on tuning this type of circuit.
Close-up photo of Dangerbot brain Another Close-up photo of Dangerbot brain Another Close-up photo of Dangerbot brain
Dangerbot's Brain (detail)

Here is Dangerbot's "brain". When I was designing him I didn't have any idea for a name. That came to me like lightning later! Notice how the "brain" kinda looks like the robot from "Lost in Space"? AH HA!! "Danger, Danger Will Robinson!!" Do ya get it? If not, watch the show. Any good robot enthusiast should watch at least a few episodes. Anyhow, the plastic bubble was from a bubble gum machine thing that gave out the small plastic egg-like containers with cheap jewelry and whatnot in them. Upon inspection I noticed that the egg fit perfectly over the motor. Between the motor and the brains there is a small encoder disc that I got in a grab bag of stuff and shaved it down to fit. I used double-sided foam servo mounting tape to attach the brain, disc, and the solar panel. For more information on my commonly used assembly techniques, please visit my Techniques section!
The Fred Head v2.2 Schematic used in Dangerbot
Here's the Schematic

Dangerbot is based on the Fred Head v2.2 Schematic above.
The Fred Head Freeform Layout Designed by Mike Scharf 
Here's My Freeform Layout

This is a Layout for the Fred Head v2.2 that I designed in Xara X. Xara is a fantastic vector based graphic design program. The power storage capacitor on Dangerbot is a 6800uF 16v Electrolytic. It was much too heavy for use on a roving bot but just the ticket for Dangerbot. The capacitor was positioned to balance the weight of the motor.

Below is another Dangerbot I built. I gave this one to my brother as a Christmas gift. The electronics are identical to the first Dangerbot. The only real difference is the base is an old 333Mhz computer processor I salvaged. It looks really cool and compliments my brother's outstanding acheivements in computer programming and computer science. I'll leave you with a few more photos of this Dangerbot before we move on. Enjoy!
This page last updated October 9, 2004