computationalhumanist.org

One of our projects is to build a sparse-array EEG system as the brain part of a brain-computer interface (BCI). This was originally the brainwave of my student Alan, who wanted a BCI for producing music from the electrical activity of the brain. (Alan also got me interested in piracetam, but that is a different post). After rummaging around on the Internet, we came across the OpenEEG Project, which was originally conceptualized as a cheap way of introducing people to biofeedback. Nowadays, it has become a conduit for labs and researchers like us who are trying to build BCIs on the cheap.

The hardware part of the project consists of a two-channel EEG system composed of an analog circuit board for collecting the signal and a digital board for digitizing it and sending it out over a serial port. The boards are built by a Bulgarian electronics company, Olimex, for about $80 a piece. Alan got a grant, and we bought a bunch of boards plus enough ancillary equipment for a single two-channel system. My students put it all together but ––– it did not work. After much fiddling and frustration, it still did not work. This was a large disappointment, because it absorbed much of our attention last semester.

A few weeks ago I met Paul Tran, who nurses computers for Psychology. Paul helped me extract some data from a Jurassic PC. It turns out that he is an electrical engineer, but for systems analysis, not circuit board diagnosis. But my juices were flowing, and I got in touch with the Electronics Lab run by the Coordinated Instrumentation Facility. But they lost their electronics guy after Katrina and have not been able to hire a new one, though they thought that Biomedical Engineering might have such people. I asked my contact in the SSE Dean’s office, who put me in touch with Cedric Walker, who I had met at a robotics gathering at the New Orleans Charter Science and Math High School.

I took my zombie EEG box to Cedric’s office Monday morning and got a fascinating lesson in circuit-board troubleshooting. He immediately determined that there was an overload, presumably from a short circuit (the LED did not come on, and the power supply got hot to the touch almost immediately). He methodically checked through the obvious things that could go wrong, mostly involving the cables that we had made and connected. He finally concluded that the XLR connectors were not connected correctly. He gave me lots of tips, like how to use the sound card in a PC as an oscilloscope. He also had a thermal wire stripper which was too cool for words. Stripping the thin wires that we worked with incorrectly is about the easiest way to screw up. So I immediately ordered one.

When it gets here, I will get started on repairing our poor beastie.