I'm not an EEG expert, but I've built EEGs for my own fun and amusement. For example, I have one that detects Alpha waves which increase in amplitude when you are ina relaxed state. The detector then shuts oft the lights in the room. Not very practical actually, but interesting.
So here's what I learned aong the way, since I had to build my own equipment, augmented with some recent inet searches:
If you are asking about the actaul EEG pickup electrodes, then I recommend for tutorial: http://www.bci2000.org/wiki/index.php/User_Tutorial:EEG_Measurement_Setup
The electrodes themselves can be purchased at medical supply houses that cater to in-home or hospice care.
If you are asking about the electronics to which the electrodes are connected, you will need essentially EEG signal conditioning amplifiers. These are characterized by:
1) very high input impedance, typically FET or BiFet input circuits, selectable differential or single-ended modes
2) selectable low pass and band pass filters to optimize SNR for the particular brain wave signal you are interested in
3) 60H/50Hz notch filter that eliminates AC pickup ( I used a 8th order filter so I could block 60Hz and still see the Beta waves and Gamma waves in the neighborhood
4) Zero-offset adjustment, either manual or automatic
5) Gain adjustment
The amplifiers are typically referenced to a reference electrode attached to the body.
The amplifier outputs are typically summed or differenced or otherwise algebraically combined to enhance acquisition of the waves of interest.
If you are interested in what to do with the data and all other aspect of EEGs, try (not an endorsement): http://anipublishing.com/
I'm not an EEG expert, but I've built EEGs for my own fun and amusement. For example, I have one that detects Alpha waves which increase in amplitude when you are ina relaxed state. The detector then shuts oft the lights in the room. Not very practical actually, but interesting.
So here's what I learned aong the way, since I had to build my own equipment, augmented with some recent inet searches:
If you are asking about the actaul EEG pickup electrodes, then I recommend for tutorial: http://www.bci2000.org/wiki/index.php/User_Tutorial:EEG_Measurement_Setup
The electrodes themselves can be purchased at medical supply houses that cater to in-home or hospice care.
If you are asking about the electronics to which the electrodes are connected, you will need essentially EEG signal conditioning amplifiers. These are characterized by:
1) very high input impedance, typically FET or BiFet input circuits, selectable differential or single-ended modes
2) selectable low pass and band pass filters to optimize SNR for the particular brain wave signal you are interested in
3) 60H/50Hz notch filter that eliminates AC pickup ( I used a 8th order filter so I could block 60Hz and still see the Beta waves and Gamma waves in the neighborhood
4) Zero-offset adjustment, either manual or automatic
5) Gain adjustment
The amplifiers are typically referenced to a reference electrode attached to the body.
The amplifier outputs are typically summed or differenced or otherwise algebraically combined to enhance acquisition of the waves of interest.
If you are interested in what to do with the data and all other aspect of EEGs, try (not an endorsement): http://anipublishing.com/
Squid based sensor is the one researchers are using for sensing magnetic field. But one should care to shield the external magnetic field since the earth magnetic field is multiples of magnitude higher than the brain magnetic field. If you wish to carry out project on MEG or EEG u can contact Mr. Janwadkar, head of Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India.
Mark fully covered the topic. In fact, there are only huge MEG systems found (with SQUIDS - not practical for home use...), EEG systems based on electrodes on the scalp (tedious to set up), but nowadays even noncontact CAPACITIVE EEG electrodes and sensors based on NEAR INFRARED SPECTROSCOPY (NIRS).
All in all for home-use, stay with electrical and you may try for little money the EMOTIV developers device.
In addition, a lot is published in context of BCI2000 - even a discussion group is out there for that purpose...