I want to build some type of electrical circuit to detect alpha, beta , theta etc. waves from the brain and maybe even show the frequency in hertz . Or at first, generate a higher power wave for my scope to read. How can this be achieved? And what would I use to pickup the waves?


To get the signal use AgCl electrode, and electrolytic gel, on various points on head, you can start with three points on forehead,look of 10-20 system of EEG for the placement of electrodes.

For the circuit part, you'll need a pre-amplifier, a nice instrumentation amplifier, a notch filter, 50/60Hz depending on your location, then a 7Hz high pass filter, to filter the galvanic response from the skin and a low pass filter at 30Hz cut-off frequency. The link below gives a step by step process.


  • \$\begingroup\$ where can I get an AgCl electrode and electrolytic gel? \$\endgroup\$ – skyler Sep 16 '13 at 23:23
  • \$\begingroup\$ If a there is a university in your area who offer a class on bio-electronics, or something related, you can ask them for the source? or perhaps going to a hospital and asking them?, are you making this as a product, or for just for making it, if you want to do something after getting the signals, buy the emotive headset(if you are willing to spend some money), and save all the hassle of making the system and focus on the main goal. \$\endgroup\$ – Hemal Chevli Sep 17 '13 at 5:32
  • \$\begingroup\$ I am just building this for fun and I am a softmore in high school, so I guess I could find a university somewhere \$\endgroup\$ – skyler Sep 18 '13 at 0:03
  • \$\begingroup\$ okay, also check out brain fingerprinting, pretty interesting. \$\endgroup\$ – Hemal Chevli Sep 18 '13 at 7:12

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