DIY Neurotech: Making BCI open-source thrusts brain-signal into a maker’s world
spectrum.ieee.org
spectrum.ieee.org
As discussed in a thread a few weeks ago, the hardware often isn't the challenging or expensive part of building a BCI system.
Electrodes and a softgoods system to reliably hold them in place comfortably is a big challenge.
The off the shelf pre-build components are expensive, uncomfortable, and/or unreliable (from our experience).
We're building a sleep wearable EEG headband which monitors sleep state and uses auditory stimulation to increase deep sleep in realtime (https://soundmind.co).
We started by working with the Open-BCI board. It was a good starting point, but once we tried to get it on our heads and sleep with it (not lying next to us on the bed), we needed to move to our own custom hardware.
That was not a big challenge. A month after that decision, we had a custom board.
But electrodes, and keeping electrodes in place, that's where the challenge is. Off the shelf stuff is either uncomfortable and expensive, or not of high enough quality to use in EEG.
We've had to not only design our own electrodes, but also the system to hold them in place comfortably while sleeping.
Many other BCI devices don't have the "sleeping" requirement, but it is still a PITA to get things going on an average users head.
Emotiv (also a local Sydney, Australia company) has some great devices which can be easily used - but I don't think they give direct access to the data.
By all means, people should play with the BCI tech, but just know that if you think you're going to buy a board, and use it in an environment where the person is not very still, you are going to run into lots of issues.
We're not focused on "hackability" atm, but if you look at Emotiv, they have a software platform, as do OpenBCI. Some people have tapped into Muse (I believe).
It seems the EEG units that have offered open APIs have mostly removed them, I'm not sure why.
What sort of "messing around with the data" would you like to do?
We have looked at opening our data to users, but seeing as we are classified as a medical device, there are considerations that there.
Totally agree that the electronics is not the difficult part (battery management, and power consumption aside). Our most loved features are the industrial design and materials science around our electrodes and ways of attaching them to the scalp.
If you're keen to connect, https://linkedin.com/in/pedalpete
We've designed and built our own electrodes too. Though we don't have to do multi-day, and we're looking for a specific signal during sleep, so probably not as challenging as what you guys are dealing with.
However, as soon as they went out of business the supply of their replacement sensors dried up, that was it.
It must be interesting what you're doing with sleep. I heard a joe rogan episode where someone used a system like that and it seems like he went right to sleep.
That doesn't stop other people from trying to sell into that space.
We're focused on improving the efficiency of deep sleep specifically, and the many physical and mental health benefits that come from that. A portion of that research is posted on our website https://soundmind.co/research
"OpenfNIRS is driven by the community to support the community in the use of fNIRS."
Edit: They sort of mention it, apparently en passant, on https://openfnirs.org/standards/:
"Shared Near Infrared Spectroscopy Format (SNIRF) is designed by the community in an effort to facilitate sharing and analysis of NIRS data."
EEG has poor spatial resolution, but great time resolution. It measures electrical activity.
fNIRS has a great spatial resolution, but poor time resolution. It measures blood flow in specific parts of the brain.
Stuff like that is useful for neurofeedback, however. I haven't tried the newer models of the Mindwave headset, but the older ones were easy to interface with over bluetooth. That's a place I might start rather than building a custom electronics board.
EMG is way more easy to control consciously and as Humans we probably have hundreds of degrees of freedom in our body for some kind of EMG, not all of it conveniently accessible of course. Controlling what consumer grade EEG devices can pick up is a lot harder. Brainwaves are "feedbackable", but that usually means changes in mental state like awareness, concentration, relaxation and so on.
Also I am a little bit afraid that some of those EEG devices on AliExpress could accidentally fry my brain so there’s that as well..
Our team used to work in metaverse tech, and now we work in BCI (for sleep), so I'm have some experience with both areas.
Even with the shocking restful night of sleep with mouth tape (a visceral need fulfilled), I’ll still forget nights and rip it off. That’s much smaller and “more convenient” than a headset.
As we see it, they made 3 big mistakes 1) awful ridiculous looking product nobody wanted to be seen in 2) way to expensive to want to try 3) not picking a target market - hey, everyone needs sleep!
We've addressed each of these
Send me an email firstname[at]our url - or hit me up on linkedin https://linkedin.com/in/pedalpete
Cheers
Measuring how "focused" or "stressed" someone is is too much of a gimmick to me.
This is from some minor diy experimentation a few years ago, might be out of date.
At least the other dev kits they compare themselves to have a prominent warning they should only be operated off battery.
However, it is fairly easy for them to update documentation to clearly say "battery only".
Last I checked the past few years made them near impossible to get as industrial orders got priority over hobbyists.
I suspect that once enough supply hits that the scalpers start getting stuck with stock they can't resell at a premium, and turn off their bots, things will improve very quickly. Of course that's just my hunch. YMMV.
Also, FWIW, there's no difficulty in getting a Pi 4 now. You only have to be willing to done one or the other of two things:
1. Pay an exorbitant price. If you're willing to buy from scalpers who scoop them up and resell them, you can buy an 8G Pi 4 right now on Amazon for the low, low price of $180.00.[3]
OR
2. Be very patient. There are authorized resellers selling at MSRP who are taking backorders and who will ship you a board as soon as they get it (relative to your position in the queue). I believe both Mouser and Newark are taking backorders for most Pi models (and one or the other, or both, have some Picos and other low end boards in stock).
The only real problem is if you want one RIGHT NOW and you want it as MSRP. And even then, if you watch rpilocator enough, you'll eventually catch a few in stock somewhere and be able to order one for immediate delivery. I understand that Adafruit receive stock fairly frequently (which unfortunately sells out very fast) but I've had luck getting Pi's from Elektor a couple of times in the past year. Or one could drive to the nearest Microcenter store that has stock, if you happen to live within reasonable driving distance of one of their stores.
[2]: https://www.raspberrypi.com/news/supply-chain-update-its-goo...
[3]: https://www.amazon.com/Raspberry-Pi-Computer-Suitable-Workst...
In this time they could have launched new products that make the most of available supply. They didn’t.
They could have recognised the hit that their b2b-first distribution model has had on their reputation and tried to make amends. They didn’t.
They could have coordinated with the alt-board suppliers to make “RPi approved” models for the Rock Pi, Orange Pi etc as a stop gap. They didn’t.
Hell, they could have bumped costs up a bit to spend on mitigating supply issues, reduce demand and burn scalpers. They didn’t.
So instead they just keep promising, just keep delaying, and we keep waiting. Even if their supply issues are through no fault of their own, it feels like they aren’t even trying.
Perhaps I'm being too cynical in lumping it with BeagleBoard but at this point to me the bbc micro:bit + MicroPython is effectively filling the educational void that Raspberry left behind.
Unsure if its actually impacting Pi manufacturing specifically, but its hit some other products I want.
Then 'all' we need is a plugin for Obsidian.
And it's not completely necessary to have a physical connection to the outside. Again, I'm not sure what the current generation of BCI implants are doing, but technically it should be possible to completely close the wound (which may "only" be a small hole drilled into the skull), then use wireless transmission of power and information. Maybe that's not convenient enough right now to get the amount of data required, but it's more than theoretically possible.
This doesn't match my understanding at all, but I'm not a medical professional. As far as I know, the brain relies heavily on isolation for protection. One function of the blood-brain barrier[0] is to prevent contamination of the central nervous system from pathogens and toxins. Bacterial meningitis is treatable with proper antibiotics, but still maintains a 10% mortality rate[1].
Additionally, simple mechanical implants (e.g. plates, screws, replacement joints) don't require interfacing with the body. They are often made of solid metals which are not bioreactive (e.g. titanium) or coated with bioresistant polymers[2].
[0] https://en.wikipedia.org/wiki/Blood%E2%80%93brain_barrier
[1] https://www.ncbi.nlm.nih.gov/books/NBK470351/
[2] https://en.wikipedia.org/wiki/Orthopedic_plate#Materials
> Immune-privileged sites include the central nervous system and brain, the eyes and the testes. Even foreign antigens accessing these tissues do not generally trigger immune responses.
https://www.sciencedirect.com/topics/biochemistry-genetics-a....
Any type of foreign body is inaccessible to the immune system, therefore prone to harbor sources of chronic infections, like bacterial biofilms.
"A significant proportion of medical implants become the focus of a device-related infection, difficult to eradicate because bacteria that cause these infections live in well-developed biofilms."
https://pubmed.ncbi.nlm.nih.gov/16353112/
No thanks, I don't want this anywhere near my central nervous system.
While the brain has better blood supply than the hard outer parts of bones, which tends to accelerate healing, the brain also relies heavily on the blood-brain barrier to keep out many threats. Crossing the blood-brain barrier is a big deal, and we shouldn't assume automatically that it'll heal better.
>>it's not completely necessary to have a physical connection to the outside INDEED! This is completely key, as having a continuous surface breaking to just under the skin is a huge infection problem that must be continually cleaned and monitored, and having one right into the brain is a truly scary high-risk proposition. So successfully encapsulating and sealing it behind the blood-brain barrier is essential.
The problem is that this means wireless communication at a meaningful data rate, through the meninges encasing the brain, the scull, and scalp. This means power consumption, power supply, and necessary power supply replacement operations - into the brain, again.
The biology side is not trivial, even as we advance the electronics side, but I'm very much looking forward to these hurdles being overcome!
Once we're out there, we're either using an array and a lot of signal processing (sort of reverse synthetic aperture radar processing) to identify detailed signals, or just using aggregate signals.
In which case, why not use more gathering points and processing power and just go outside the scalp, avoiding infection problems entirely?