Alright, so here it is! Finally, after all that experimentation, it all boils down to this. As of now, this schematic incorporates only ONE EEG channel measured by an INA118, which is then fed to an inverting amplifier followed by a Fliege Filter (cut off frequency is set at 33.86 Hz). I previously used a dual supply to power the circuit, but with the help of TLE2426, I’ve been able to use just a single +5V supply (which comes from a 7805 connected to a 9V battery). If you have any questions at all, feel free to post here or email me at:
For the electrodes, I got good results by replacing the gel layers in medical electrodes (already used) with sponges soaked in warm saline water.
- Precision analog multiplexer to expand this circuit into 8 or more EEG channels
- Using this circuit for neuro feedback – specifically Alpha & Theta training
In case you’d like to read more about creating your own EEG circuit, check out Solson’s EEG page. He’s got some neat info on his EEG hardware as well as on Neuro-feedback.
By the way, I’ve also been working on a circuit that kinda replicates the results that you can get from Dr. Robert Becker‘s Brain Tuner. You can read more about the Brain Tuner here. basically incorporates Cranial Electro Stimulation at very low currents. In my version of this device, I’ve programmed a PIC 16F628A to generate specific sinewave frequencies (very low Hz) followed by a low DC current that suddenly switches polarity at the required moment to place the user in a light alpha state. More on this later…