We are targeting the development at affordable EEG hardware and specifically have the OpenBCI system in mind. A 3D printed headset has been constructed in the OpenBCI project, but that is not (yet) easily available. Hence I am currently exploring some ideas for electrode attachment on my own.
Although easy to put on, a hard-plastic headset is not trivial to construct. The standard (clinical and research) EEG cup electrodes that we work with are usually attached to a long wire. Using a glob of Ten20 electrode paste you can stick them to the scalp. Subsequently connecting a bunch of long wires to a wireless EEG amplifier leads to the question how to bundle and lead these wires from the scalp electrodes to the amp.
I came up with the idea to use an elastic sports headband. This allows to attach the wireless amplifier to the head, and consequently the electrode wires would be channeled along the headband. Here you can see the components that I started with (minus the EEG amplifier):
The headband is one that I picked up in a local sports shop. It consists of a sleeve of flexible fabric that is relatively thin. At the placed where the fabric needed puncturing, I used some iron-on interfacing to strengthen it and prevent the holes from further tearing.
This is the end result. Although I am presently experimenting with a Jinga-Hi JAGA16 wireless EEG system (which is the smallest and most portable system that I know), here I only used 8 electrodes for the EEG and 2 for the ground and reference.
Soldering the electrode leads to the miniature connector was the hardest task. The 18 pin (arranged as 9×2) connector is only 12 mm wide, which means that for each pin there is only about 1.2 mm space.
Note that the PCB board with the yellow wrapping is actually the full 16 channel wireless amplifier. It is powered by a (cell-phone type) LiPo battery, which is as large as the EEG system. Data is transmitted over Wifi and can be streamed and analysed in MATLAB or Python using FieldTrip.
Here I am, wearing the first prototype electrode headband. Two electrodes (ground and reference) go behind the ears, the other eight electrodes are approximately placed at F3, F4, C3, C4, P3, P4, FCz and CPz. The wifi EEG amplifier and the battery can conveniently be tucked away in the two flaps at the back.
