Thread: Sofia-EOG - open source software and hardware for REM detection

Well there's the fundamental problem with electrode displacement. As Nazrax pointed out it's very hard to invent a design that is comfortable and stable. Frankly I think the Aura is nicely thought out if they get a good signal. As far as I know if you have good electronics (with filters, good amplifier, insulation everywhere, etc.) the signal can get much better, but as you said - their placement is disadvantageous (I've tried such a placement - the signal is weaker). So in the end it all depends on the testing - their electronics might compensate for the placement. I, myself, aim for simplicity, but as it turns out I'll have to add a preamp and filters to the electrodes, because sometimes the noise scrambles the in-amp and if I push the electrodes around a little bit it gets better again, but I can't do that while I'm sleeping

Edit: A friend of mine helped me figure out (hopefully) what the "state" that the in-amp got in was. As it turns out an op-amp can get into comparator state where it generates exactly those square waves, and that probably happened because the sound card fed some current back in the amplifier (because computer microphones get powered by the sound card, and I was using a mic jack where the tip and ring were shorted).