Re: [buildcheapeeg] Re: I published current design at SourceForge

From: Doug Sutherland (wearable_at_earthlink.net)
Date: 2001-12-03 22:20:03


Over on the biofbp group, Rob Kall replied ...

> Congratulations Yaniv. It would help to state the specifications
> for the device you've developed. Practitioners and informed
> consumers will want to know the details.

Rob is a board member and public relations chair for the Association
for Applied Psychophysiology & Biofeedback (APBA). He also founded
the Winter Brain meetings. If there is anyone that needs to be
informed and convinced about OpenEEG, this is the guy. It sounds to
me like he is interested, but just like I said he wants details.

Take a look at the brainmaster system specifications:

BrainMaster 2E / BMT System Specifications

Built In Protocols:
ALERT(Focus, Alertness)
DEEP (Deep Relaxation)
FOCUS (Concentration, Focus)
PEAK (Peak Performance)
RELAX (Relaxation)
SHARP (Mental Fitness)

Communications:
Interface: RS-232 port (25 pin female)
Speed: 9600 baud
Isolation: optically isolated to 130 volts (continuous) or 1500
V (1 sec)

EEG Amplifiers:
Gain: 20,000
Input Impedance: 10 Gig Ohms
Input Noise: <1.5 micro volts (peak to peak)
Bandwidth: 0.5-40 Hz
Common-mode rejection: > 110 dB

Digitizer
Type: successive approximation
Sampling rate: 120 samples/sec
Conversion Rate: 16 microseconds
Channels: 1 or 2
Resolution: 8 bits
Accuracy 1/2 LSB

Frequencies Resolved
(Nominal - User Adjustable)
Delta: 1-3 Hz
Theta: 4-7 Hz
Alpha: 8-12 Hz
Low-Beta: 12-15 Hz
Beta: 15-20 Hz
High-Beta: 20-38 Hz
Gamma: 38-42 Hz
Selectable Filter Sensitivity

Displays:
Raw waveform, live and playback
“Chaos” phase-space display
FFT frequency spectrum
BrainMirror frequency spectrum
Compressed spectral array
“Thermometer” bar graph values
One-, Two-dimensional trend lines
Component counters
“Brain-Man” game
“Boxes” game
“X-wing” game
Numeric display
Coherence Display
Percent time over threshold
Statistical summaries

Here are the WaveRider specs:

Optical isolation on all data lines
Two independent differential channels with eight gains each.
One channel of GSR with eight automatic offsets
Sampling rate per channel: 128 Hz
FFT Frequency resolution: 1 Hz
A/D resolution: 8 bit
Common Mode Rejection ratio: 100 dB minimum
High pass filter: .5 Hz
Low pass filter: 40 Hz
-72 dB at 60Hz or 50 Hz
Specifications subject to change without notice

This is the kind of info you need to provide before any of the
BF/NF people will even look at the OpenEEG design. At bare
minimal you need the info as above for WaveRider, but I also
think that more info is needed on the software, like the
brainmaster specs show. One other thing to consider, maybe
you should put OpenEEG next to the others in this chart for
an exersize in comparison, to see how it stacks up:

http://www.brainmaster.com/productinfo/bmr2emodule/brainmaster/comparison/comparison.html

-- Doug



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