If anyone is interested, I'm actually in the process of launching a similar board. Much lower noise (by about 5x, custom AFE), tuned for load cells, 4 simultaneous-sampling channels.
There are multitudes of neuro research projects using animals as test subjects that could save a lot of money using a tool like this. If the research project is able to use a device like this rather than a human verified device. From my limited knowledge, these projects do their best to be very kind to the animals being tested. A device like this wouldn't need to be enclosed within the animal, so less risk of harm right away.
In Africa, clever locals built a humidy crib from car parts. It ended up not working as a product, but a great idea. In the link below, its celebrated as a commercial failure to learn from.
I think EEGs (Electro EncepheloGraph) can produce a far more detailed, brain related view of what an ECG (Electro CardioGraphs) can produce. An EEG can of course look into many other brain related functions and issues.
Creating a low cost version of an EEG will hopefully at least provide some thoughts to the engineers of commercial EEGs.
Commercial, medically verified devices are tied down in many ways...
- Full checks of the software and hardware design,
- backwards interoperability and compatibility for devices and their connections over their lifespan
- A full medically based software/hardware quality check,
- Providing very detailed documentation,
- doing a full test cycle around every device,
- Interacting with doctors and health experts to fully characterise the domain and typical device use. This is great to do as an engineer, but is expensive for the company :-)
- Older (often slower) more fully field verified/trusted chips for any logic are used, since they have a large measure of reliability, reducing the risk you'd get from new products.
The list above is from memory. Engineering around devices like this become part of the culture of the company. Each region (US, Europe, Oceania) have their own requirements and levels of completeness. The big market for any medical product is the US. It's FDA in the past has been the most important regulatory body to satisfy to allow access to the US market. Several other markets use the FDA as a base for their own standards too.
This process takes several years and millions to complete. Its a very necessary step. Think of the Therac 25, https://en.wikipedia.org/wiki/Therac-25 . The mistakes in this device design caused fatalities.
I used to work for Cochlear. Their devices have had some issues, but overall I think they have a very good record. The verification/quality checks outlined above are super necessary.
Anther Oz company Telectronics, built many pacemakers and unfortunately made a design mistake in the choice of material for a lead feeding the part of the device that fed the therapeutic current to the patient. After time, the lead cracked. Failure of physical integrity in a fully enclosed medical device is quite a bad failure mode. I believe The company lost 75% of its share price overnight when the issue was reported. https://en.wikipedia.org/wiki/Telectronics
When this device becomes fully wireless, its risk will drop somewhat.
This project is awesome also as a teaching tool for people wanting to join companies that make medical products. They'll be able to look over a modern design and discover what's involved.
Please jump in and make any additions or corrections to the above.
Part of what you're paying for with the ADS1299 is simultaneous sampling, which you can get by without. You could use a single-channel 24-bit ADC and multiplex it yourself with generic analog switch ICs. That gives you a much larger array of part-selection options.
Great project. Put up a small issue on Github for a couple of the links in the article.
https://github.com/Cerelog-ESP-EEG/ESP-EEG/issues/1
A quick look over the other links looks like they're okay, follow them instead for the moment.
Hey, I'm not affiliated with Cerelog, but I'm the author of the article and those are my typos. Fixed!
Thanks for pointing this out.
No prob. Great device and a useful article. I thought the author was part of the org. Well done.
Should I delete the issue since its not their article?
I have a much larger screed in another part of the tree of comments too. It's a case of braindump, TLDR.
Related:
Show HN: Open-Source 8-Ch BCI Board (ESP32 and ADS1299 and OpenBCI GUI) - https://news.ycombinator.com/item?id=46502051 - Jan 2026 (21 comments)
If anyone is interested, I'm actually in the process of launching a similar board. Much lower noise (by about 5x, custom AFE), tuned for load cells, 4 simultaneous-sampling channels.
Cool. What are useful aaplications of diy EEG?
Could do more accurate but less comfortable sleep tracking
TLDR :-)
There are multitudes of neuro research projects using animals as test subjects that could save a lot of money using a tool like this. If the research project is able to use a device like this rather than a human verified device. From my limited knowledge, these projects do their best to be very kind to the animals being tested. A device like this wouldn't need to be enclosed within the animal, so less risk of harm right away.
In Africa, clever locals built a humidy crib from car parts. It ended up not working as a product, but a great idea. In the link below, its celebrated as a commercial failure to learn from.
https://www.bbc.com/future/article/20140430-why-bad-inventio...
There's another affordable humidy crib that won a design competition here, https://www.theguardian.com/global-development/2014/dec/25/i...
I think EEGs (Electro EncepheloGraph) can produce a far more detailed, brain related view of what an ECG (Electro CardioGraphs) can produce. An EEG can of course look into many other brain related functions and issues.
Creating a low cost version of an EEG will hopefully at least provide some thoughts to the engineers of commercial EEGs.
Commercial, medically verified devices are tied down in many ways...
- Full checks of the software and hardware design,
- backwards interoperability and compatibility for devices and their connections over their lifespan
- A full medically based software/hardware quality check,
- Providing very detailed documentation,
- doing a full test cycle around every device,
- Interacting with doctors and health experts to fully characterise the domain and typical device use. This is great to do as an engineer, but is expensive for the company :-)
- Older (often slower) more fully field verified/trusted chips for any logic are used, since they have a large measure of reliability, reducing the risk you'd get from new products.
The list above is from memory. Engineering around devices like this become part of the culture of the company. Each region (US, Europe, Oceania) have their own requirements and levels of completeness. The big market for any medical product is the US. It's FDA in the past has been the most important regulatory body to satisfy to allow access to the US market. Several other markets use the FDA as a base for their own standards too.
This process takes several years and millions to complete. Its a very necessary step. Think of the Therac 25, https://en.wikipedia.org/wiki/Therac-25 . The mistakes in this device design caused fatalities.
I used to work for Cochlear. Their devices have had some issues, but overall I think they have a very good record. The verification/quality checks outlined above are super necessary.
Anther Oz company Telectronics, built many pacemakers and unfortunately made a design mistake in the choice of material for a lead feeding the part of the device that fed the therapeutic current to the patient. After time, the lead cracked. Failure of physical integrity in a fully enclosed medical device is quite a bad failure mode. I believe The company lost 75% of its share price overnight when the issue was reported. https://en.wikipedia.org/wiki/Telectronics
When this device becomes fully wireless, its risk will drop somewhat.
This project is awesome also as a teaching tool for people wanting to join companies that make medical products. They'll be able to look over a modern design and discover what's involved.
Please jump in and make any additions or corrections to the above.
tl;dr it uses
Texas Instruments ADS1299 (24-bit, 8-channel) analog-digital converter
There is no way to do what that chip does for less, maybe 7$ less but then not as good. They have priced it perfectly and I hate them for it.
https://www.digikey.com/en/products/detail/texas-instruments...
Part of what you're paying for with the ADS1299 is simultaneous sampling, which you can get by without. You could use a single-channel 24-bit ADC and multiplex it yourself with generic analog switch ICs. That gives you a much larger array of part-selection options.
Or try the newer ADS122S14.