Steve's Things

I was thinking about cockroaches after seeing some sort of program on the subject. It brought me on to thinking about insect locomotion and the way complex moves are carried out by creatures without a central nervous system. It then started to occur to me that the reason that these creatures (or any other for that matter) function is that there are a great deal of stimuli. An insect’s leg, for instance, has thousands of sensory organs to determine touch, temperature an various other external events that aren’t processed anywhere centrally. The thought the occurred to me about the notion of how a nervous system might work. Hence my latest, yet ugly, creation. The Roboto v2.

This is the robot from the front. Currently it has 6 ultrasonic range sensors. This was the best thing to test my idea.

I had a frame for a robot I had already assembled and really didn’t get anywhere with it until I had this idea. Basically the idea is to have a matrix of variables, in this case a 10×10 struct array. Sensors are ‘bound’ to certain segments of the matrix. The matrix elements also communicate with the adjacent nodes to relay positive or negative stimuli. These stimuli make their way to the motor controls which are bound to other matrix nodes, in my case, elements several nodes away on opposite sides of the grid. The values expressed in the node are translated into motor movement.

Roboto V2.0 from the top, A tremendous jumble of wires.

What I have right now is functioning better than I hoped. I made close proximity ‘painful’ and moving forward ‘pleasurable’. A close proximity on the side will cause pain on the same side. Currently the robot seems to find open areas but doesn’t stay in them. I did fudge some things which are.

• Output to the motors is kind of jury-rigged to disallow stopping by ensuring that at least one wheel is at maximum motion based on a weighted average.
• the sensory input is weighted at the nodes. This was needed simply to make it function correctly.
• I have a constant ‘pleasure’ value plugged in to make the robot strive to move forward. otherwise it would probably just stay in one place.

Well, I’m going to try some other things and add more stimuli like IR sensors, compass, accelerometer and a gyro. We’ll see if I can get something interesting out of it. An in case anyone is wondering about the build here’s a point by point list of what I used.

• Arduino Mega2560
• A robot chassis that I bought off EBay. It’s not bad.
• Built the motor driver board myself with an SN75441one and a 5A linear LDO reg.
• 7.4v LiPo battery, 850mah for direct drive to the motors
• A little cheap bread board
• and LED-KEY module, based off the TM1638, very handy modules
• lots of male to female wires!