ERC
The Experimental Robotic Contraption

ERC is a small computer, a few motors, some cardboard, and a bunch of K'nex. For a long time it was a mobile robot, with differential drive, and I used it for many navigation experiments.

At one time it had a downward looking light detector, and would chase the spot of a flash-light shined on the floor in front of it. Then it had an upward looking light detector, which would use a fixed light source as a navigation beacon. For a long time it had a scanning optical range finder and behavior pictured above and described below.

Computer

A Motorola 68hc11 on a modified BotBoard. An expansion board provides 32k bytes RAM, 16 bits of parallel input, 16 bits of parallel output, and 32 multiplexed analog inputs. This is all a hand wired rats nest, but it works better than it looks.

Range Finder

It has an oscillating scan platform with two seven zone, convergent mode, infrared, range finders. Seven IR emitters mounted behind the upper lens (pocket magnifier), produce beams that converge with the field of view of a detector (behind the lower lens), at different distances from about nine inches away, to nine feet away. ERC divides this 360 degree view into 32 directions, and for each gets a distance of one to seven, or beyond range.

Crowd Interactive Behavior

ERC's behavior has two main modes, attack, and flee. In the flee mode he will steer away from any thing in front of him, and will stop only when he sees nothing is within nine feet. In the attack mode he will steer toward, and follow what ever is in front of him. If it stops moving ERC will move up to it and stop, wait for a few seconds, then get bored and turn to attack in another direction. All of this software uses a subsumption approach somewhat like Rug Warrior, implemented in assembly language.

Update

At this time ERC has been dismantled. Its scan platform had broken and I wanted to play with the K'nex. I still have all the parts and intend to turn it back into some kind of robot someday. In the future these parts may be something completely different, an arm perhaps?