Frankenstein

Frankenstein the Walker

Frankenstein is a 2 motor walker I built directly from the pages of Junkbots, Bugbots, and Bots on Wheels. He uses 2 modified servos using the rear one for forward thrust and the front one for lift. The legs are made out of standard house wiring and are easy to bend. This makes it very easy to experiment with different leg shapes. Can you guess how he got his name?

Frankenstein (underside)

Here you can see the rear motor centering spring. This spring causes the rear motor to more easily return to center much like your fingers go to a natural resting position when relaxed. The rubber bands on the front (lift) motor do the same thing. I've found that using these small rubber bands makes it very easy to adjust the amount of centering force. This is a critical adjustment to get right. The blue flat batteries on Frankenstein's sides were FREE. I got them from the local Radio Shack store before they threw them away. They were inside a cell phone battery and were brand new! I have gotten many batteries in this way from them. The phones they were made for are now extinct, but the batteries live on.

The Brain of Frankenstein

This is type of circuit is called a Master-Slave Bicore. This means that one section keeps the timing while the other section follows with a short delay. There is a third section called the Reverser section. This part isn't being used yet but will be attatched to tactile sensors. When one of the sensors is triggered, the Reverser causes a phase shift of about 180 degrees on the rear (thrust) motor. This will cause Frankenstein to back away from obstacles and set off in a new direction. The wires hanging up in the air are resistors. They plug into miniature sockets on the brain to adjust many different aspects of timing on the bot. Once they are adjusted to give the best performance, they will be clipped and neatly positioned close to the brain.

I will be adding the schematic and freeform layout for this bot at a later date.

For information on how to build your own 2-Motor walker, pick up the book "Junkbots, Bugbots, and Bots on Wheels" at Solarbotics.Com or check out their excellent library on the subject at Solarbotics.Net.