New & improved EEG headset with OpenBCI

Oh, how things have changed over the past 10 years! At the time when the only option you had to dive into Neuro-feedback was to create or build your own circuitry, spend hours and weeks fretting over the instrumentation board, matching the channel inputs correctly, etc. Now, you have plenty of options to choose from, so you can save yourself all the grief and heartache. If you have the money and you’re only interested in Brain-Computer applications, then either buy a wireless EEG headset from Emotiv (this company offers a decent 5 channel to 14 channels, but you have to PAY for being able to read raw data from the headset, which sux!), then there’s Muse, which is a sleek-looking brain-sensing headband that seems to be popular for meditation… and finally, NeuroSky (honestly, it looks like a toy headset to me with just ONE channel). This blog does a great comprehensive review of most popular & commercial EEG headsets, as well as the open-source options out there: https://www.diygenius.com/hacking-your-brain-waves/

However, if you have a small budget and don’t mind tinkering around but at the same time, if you dont want to re-invent the wheel, then I’d heartily suggest you get yourself the 4-channel Ganglion board from OpenBCI, which costs about $200: https://shop.openbci.com/collections/frontpage/products/pre-order-ganglion-board?variant=13461804483
I got mine last month and this is what it looks like:

OpenBCI Ganglion board

OpenBCI Ganglion board

The beauty of OpenBCI’s design astounds me and I’m SO impressed with what you can record with this board: 4 EEG channels + Accelerometer data, and you are not limited to recording only EEG data, you can also use it for ECG or EMG recordings as well! And since it has Bluetooth-LE onboard, that means you can wirelessly transmit your EEG data straight to your system. And OpenBCI’s software is just as impressive, not only does it stream raw EEG data in real-time for FREE (Emotiv & NeuroSky, you could learn a thing or two from these guys!), but you can also monitor the Accelerometer (which detects 3-dimensional movement of the head) AND the software also has  an Electrode Impedance checking section to boot! The Impedance checker is VERY handy, helps you to figure out if any of the electrodes are sitting loosely or if they require more gel to be added, etc.

Now if you have another $300 to spare, then it would make your life a LOT easier if you got yourself the Ultracortex Mark v3 or v4 headsets, because they’ve been designed for fast application, doesn’t require electrode gel (since they use dry Ag/AgCl electrodes) and most importantly, the Ganglion board fits as smoothly as a baby’s butt at the back of the UltraCortex headsets 😀  I would’ve preferred to get myself the Ultracortex Nova atleast, but the DIY experimenter in me just couldn’t stand the thought of having to waste the previous EEG headset that I had already built. So, I decided to incorporate OpenBCI with my existing EEG headset.. I added the board on top of the headset, fixed it with a few screws, melted a bit of plastic to make a small seat for the 9V battery to sit comfortably and tied it securely to the headset with good ole electrician tape! Here’s what it looks like:

So now, my EEG headset is a mixed EEG system and allows a total 6 channels (4 from OpenBCI + 2 from OpenEEG/my circuit). The trick to combining both systems seamlessly is to ensure that both systems share the same floating Driven Ground (i.e., the DRL in usual parlance) and the way I achieved this was to build a couple of earclip electrodes… from clothes pegs! 😀 I combined the pegs with pure silver electrodes that I got made especially for this purpose and they work extremely well, even without electrode gel! So, one of the earclip electrodes acts as the Reference electrode (I used it on the left earlobe). And with the other earclip, I’ve sandwiched the right earlobe between two DR electrodes, i.e., combined both Driven Grounds so that the DRL electrode from OpenEEG sits on one side of the earlobe while the other side is covered by the Driven GND from OpenBCI. This way, both systems will share the same Driven Ground, thereby ensuring that all readings are correctly recorded with respect to the established common reference.

 

To record data from the Ganglion, I’d need the Bluetooth CSR dongle for OpenBCI, which interfaces well with their open-source software, whereas with my old circuit / Olimex, all recording takes place through a USB cable. So far, the readings I’ve taken from both sets of electrodes and systems look great (except for one channel but I’ll have to look into that). I’ll add more info and pictures the next time I take an EEG recording with my new & improved OpenBCI/EEG Headset. Ciao for now!

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~ by teknomage on March 14, 2017.

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