Brain Blood-Flow Biofeedback meets affordable IoT!

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A revolutionary new biofeedback method - now open sourced for the ESP32!

HEG stands for Hemoencephalography - the measure of blood flow in the brain. This is intricately involved in brain activity and consciousness - and it turns out you have direct control!

Until now it's never been affordable or accessible to experience this unique yet simple tool. Light penetrates through our skull easily so we can use pulse oximetry to measure the surface blood flow information in your brain! It turns out stress and poor health have huge impacts on our brain's blood flow activity and can straight up shut parts of itself down in response. Our frontal cortex also increases blood flow activity when we are focused. The HEG allows us to make basic measures of this and more! We are building a full web based suite to go with it - for free!

Special thanks to the inventor at the Biofeedback Institute of LA for their guidance and support, and to my friends for making this possible

Hey everyone! Please check out our work at our github page and our website, and join us in developing the future of biofeedback! The HEG has so much potential, and we opened the doors to everyone with one of the most affordable and easy to use biofeedback devices ever! This is an evolving project. We have developer DIY kits available for sale on crowdsupply or you can contact me directly, and most of our software features are in a very functional state but not polished.

I designed these kits to be very easily assembled by hand within 15-30 minutes and be quite durable. The designs are also freely available if you want to come up with your own. I want the community to help develop the HEG, it's so cool it's gotta happen!!

There is a long history of blood flow training, from ancient breathing techniques to enter different mental states, to modern ace pilot training to stay conscious under high g's. It is also a powerful tool to maintain our mental health - since nothing works without good fuel flow from your heart and lungs, as well as it enabling your immune system to function better. It also turns out nothing stops blood flow to the brain like stress and poor health! It's an incredibly sensitive organ, and the HEG can help you keep in touch!

HEG neurofeedback training is akin to aerobic exercise - but for your brain! It gets weirder, though. Like an antenna, our body can learn to use the HEG signal to directly elevate a targeted area of our frontal cortex and likely the rest of our brain - just like we can do in other parts of our body. There are many questions about how this might enable new types of brain-computer interfacing.

HEG sensors can even be arrayed to do diffuse optical tomography and generate a 2D image of surface brain activity. It also turns out that if the sampling rate is fast enough you can even see brain wave patterns within reflected light from blood flow! You could probably accomplish a lot of this with our off-the-shelf hardware. 

  • 1 × Adafruit Huzzah32 Feather Alternatively a LOLIN32 V1.0.0
  • 1 × ADS1115 w/ PGA 16 bit ADC 860sps
  • 1 × OPT101 Opto and Fiber Optic Semiconductors and ICs / Optical, Photoelectric Sensors and Switches
  • 1 × AN1102W Optoelectronics / Misc. Optoelectronic Components
  • 1 × BR1102W LEDs and Accessories / Light Emitting Diodes (LEDs)

View all 7 components

  • 1
    Sensor: OPT101

    Place the OPT101 through the hole from the backside where the solder pads are exposed. Make sure the notch on the OPT101 is facing the 6p6c connector direction. Solder it down so it is about flush with the stiffener on the face.

  • 2
    Sensor: LEDs

    The LEDs have tiny green notches on them. Put the Red and Infrared LED in each of their respectively labeled positions with the green notches facing toward the 6p6c connector (direction also marked by little white notches on the PCB). If you forget which LED is which you can always get the Red one to visibly light up with a multimeter set to Diode mode. 

    Add the 33 ohm resistor to the 62 spot and the 62 ohm resistor to the 470 spot. We had to lower the resistance on the IR LED due to sensitivity issues that cropped up on lower power settings. Make sure the resistors are on the back side facing away from your head so it doesn't feel awkward. Clip the leads. Finally, add the 6p6c connector to the correct side.

  • 3
    Microcontroller assembly

    This part is fairly self explanatory as everything is clearly labeled. First add the 2.7kOhm resistor and the ADS1115. The ADS1115 has clearly marked VDD and A0 pins to indicate the direction it should be placed on the hub board. Clip the leads to make room for the ESP32 on the other side.  Do this first because it won’t easy to add these after the ESP32 is soldered.

    If you are using a Huzzah32 form-factor board, the ADS1115 comes pretty close to the pin holes (sorry!) but just make sure you’re not completely covering them with the ADS1115. I recommend putting the pin header for the ADS1115 through the top of the ADS1115 to minimize the form factor. After soldering these parts, clip the leads as short as possible. There are 2 compatible popular ESP32 boards, the LOLIN32 and Huzzah32 Feather, that only fit in their respective slots on the correct side of the PCB, go ahead and add it, then finally add the connectors. Lastly, optionally, cover it all up with electrical tape to prevent shorts or static damage.

View all 6 instructions

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DOBsby wrote 01/08/2024 at 16:44 point

Looking at the HEGduino V2 on Crowd supply now. Wondering if I can find more details about seeing brainwaves with HEG/fnirs

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Tom Meehan wrote 08/22/2020 at 19:59 point

Great project, received your kit yesterday and put it together.  Flashed the firmware today and it's working great.  I look forward to experimenting with it.  The web apps are very nice.  Don't know why this isn't getting more likes here since it seems promising and research seems pretty solid.

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