Brain Child

A bit of Background

My arts grant project involves a large-scale brain-controlled drawing machine. I've made another brain-drawing machine, known as RedGreenBrain earlier this year. It was shown at CCRMA's Modulations and Maker Faire. Still need to compile all the video from those events, but it was a hit. The robot used EEG technology from Neurosky. A pen moved based on the user's attention and meditation levels, and the resulting patterns were very geometrici yet appeared to have a human touch.

Photo: The RedGreenBrain at Maker's Faire, May 2011, San Mateo, CA.

And Now...
The new Robotic MindMapper that I am working on will have a more challenging control scheme, and will move in spiraling patterns so long as the user concentrates. I acquired some 80/20, timing belts and pulleys for prototyping. Right now I'm trying to figure out if the motors from RGB can be used. It would have been easier to use steppers to position control the motors, but since I'm using timing belts and encoders, I thought maybe these big DC motors would have a smoother motion.

First, I mounted the motors to a wall, about 6ft apart and 7ft from the ground. The base in the center of the belts will soon house the drawing medium and a mechanism to keep it against the wall in drawing mode. It doesn't look like much yet, but with my supply of 80/20 and by ordering longer timing belts, the workspace is limitless.

It actually took me three days to debug this setup and get the motors to move as desired. I am using a motor driver (the Procyon v.1 by Pascal Stang). And unfortunately the documentation was wrong on the example pin outs! Luckily, I got it moving on an example loop. These videos show the range the can be accomplished, by driving the motors alone, together, and clockwise/counter-clockwise.

And Next...

Things that will get done this week:

1.) Talking to the POTE organizers and filling out display requirements. Will have to figure out if I should make a fake wall for the exhibit or some other way to mount the robot.

2.) Testing the motor motions with the encoders. Using the encoder to draw out a circle.

3.) Order longer belt material to reach more of the 6ft workspace if possible.

That's it for now!