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DIY EEG see whats on your mind - Any Ideas on how to build one? Answered

A Electroencephalography (eeg) is a divice that measure electrical signals from the brain. There is a site called http://openeeg.sourceforge.net/doc/index.html which has plans, but its hard to follow. Wanted to see if anyone was intrested in putting together a instructables to make one of these on the cheap and easy to build.

Think this starwars toy could be a starting place? http://bit.ly/71mzRi
 It's called Force trainer and I guess it's suppose to read your brain waves. Sound like a load of crap to me, but might be a place to start.  


This toy is really a galvanic skin reaction detector and has little to do with brain waves.

It is not a galvanic skin response detector. It is an actual beta wave detector. A GSR unit would be easy to hack by wetting the sensor pads. The unit was developed using EEG data and has algorithms to detect beta wave activity. As beta waves increase, the fan speed increases and the sphere rises. Take a look at the info available...

EEG- excellent example of "the whole is greater than the sum of the parts".  EEG shows the brain is active but can show very little of what the brain is doing.   Many medical diagnostic tests suffer this shortcoming- they measure something but do little to explain the meaning of the measured values. 

Data is easy to collect, very difficult to comprehend.

I've never seen the Star Wars Force Trainer, it is claimed to measure "brainwaves through dry sensor technology and can determine the differences between alpha, beta, gamma and delta waves": (http://www.starwars.com/vault/collecting/20090209b.html ).  Maybe it does.  Notice the words, "dry sensor technology."  Electrodes are part of the problem in measuring EEG (they have electronic drift), as are muscle twitches, which have a much greater signal strength than brain waves.

As frollard and orksecurity say, an EEG doesn't show how you think.  The appearance of alpha waves show that you are relaxed (http://www.numbers1317.org/file_23_television_03.html ).  Rolling your eyes up also causes alpha waves

If you are interested in building one, there are instructions at  http://www.madsci.org/posts/archives/1998-10/908997338.Eg.r.html 

Those 'star wars' toys aren't all that bunk - they just measure total brain activity - if you relax it goes down, if you tense up it goes up; so it can be used to perform simple tasks.

Many of the toys have you fight with a friend to be more relaxed to move a physical object around - like a reverse arm wrestle.

Websearch for alpha wave monitors, which are a simple EEG "toy" often used for relaxation training. Schematics should be fairly widely available.

Full EEG will tend to be complicated/expensive since there are a lot of signals to be filtered and correlated.

And it still won't show "what's on your mind" -- it just shows your mind in operation. Correlating that to anything more than some general mental states is ongoing research.