HEGduino: Measure real-time cerebral blood oxygen levels (all open source)

HEGduino is an affordable and easy-to-use biofeedback kit. It uses red/infrared light sensing to determine changes in blood oxygen levels in the brain in real time. Tracking changes in blood oxygen in your brain can provide direct insights into your brain activity. HEGduino makes blood electroencephalography (HEG) biofeedback simple, affordable, and easy to hack.

The "HEG" in HEGduino stands for hemoencephalography, a non-invasive biofeedback method similar to EEG neurofeedback. HEG detects regional changes in brain energy consumption through changes in blood oxygenation. The HEGduino allows you to see in real time how your brain's blood oxygen levels respond to your thoughts and actions, resulting in a simple yet elegant biofeedback system. By focusing, breathing and relaxing, and watching the reactions on the screen, you can easily influence and ultimately control the local blood flow in your head. By doing some exercises with the biofeedback provided by HEGduino, you can exercise your brain and make it healthier through this type of physical therapy.

Use the device in less than ten minutes to learn how to directly change blood flow to your brain. Neurons do not store energy, so regional brain activity is closely related to changes in blood oxygen (fuel), where healthy blood flow patterns (carrying oxygen to your cells as needed) are critical for high function and growth of the brain.

HEGduino and biofeedback applications

     Brain Exercise: Do "brain push-ups" to increase brain blood oxygen levels as an educational, clinical or hobbyist tool.
     Stress monitoring: Preventing student or professional burnout.
     Study: Neocortical function measured by changes in blood oxygen ratio.
     Biohacking: Modify the HEGduino and its applications to suit your needs. It's open source!
     Competitive Benefits: Increased long-term awareness and awareness of playing your favorite sport or esports.

Technical specifications

Controller board:

         ESP32 based control

             Adafruit Huzzah32 (4 MB flash, but less I/O)

             WeMos Lolin32 V1.0.0 (4 MB flash but more I/O)

         ADS1115 16-bit 860 sps ADC

         Maximum I/O lines:

             32 inputs/outputs

             26x digital pins (3.3 V) - all PWM functions (two occupied by LEDs)

             18x analog pins

             3x UART

             3xSPI

     Sensor board:

         Flexible circuit board to conform to the shape of your head and headgear

         650 nm 50 mA red LED

         950 nm 50 mA IR LED

         OPT101 Monolithic Photodiode

         Connects to receiver via CAT3 connector/wire