Some progress with the electrodes has been done! From left to right: base unit, electrode, ground electrode. Ali from Media Factory soldered the tiny SMD’s to the board (like a boss). We still need to attach the resistors and capacitors and some copper before we can test it out.
The PCB’s were designed in Eagle CAD according to .
 Y M Chi, P Ng, E Kang, J Kang, J Fang and G Cauwenberghs. Wireless Non-contact Cardiac and Neural Monitoring. Wireless Health 2010.
Our plan is to make a hat that reads the wearers brain waves on a couple of electrodes and interpolates the signal to project the brain activity on LEDs on the hat. We would also like to add wireless communication and GPS to be able to publish our brain activity online and locate different thoughts to different parts of the city.
We will make our own capacitive EEG electrodes that don’t require direct skin contact, and will thus work through hair and fabric. The electrode is based on a circuit designed by researchers at UCSD.
The EEG data can be analyzed with FFT to recognize the spectral components. Choosing the alpha band (8-13Hz) and calculating its total power is a good indicator of brain activity, the total activity seems to be inversely related to alpha activity.
The hat will be covered with RGB LEDs and light fibre. We will use 4 electrodes, but by averaging we can make a “scalp map” with more LEDs. This is inspired by scalp maps used in brain research.