From: jiva_at_humboldt1.com
Date: 2001-05-02 21:12:44
Iteration 3: Wednesday, May 02, 2001
I'm going to start with a list here for the hardware specs,
requesting feedback from list members with more information than
I have. When somewhat gelled, I'll convert it to HTML format
for the website. This is only the first "rough draft" and request
for feedback. All useful information will be included in future
iterations.
* Hardware
* The "Black Box":
Current prototype is a design by Joerg Hansmann.
http://www.jhansmann.de/eeg/eeg.html links to info on
the RS232 and Gameport designs with the RS232 unit being
the current design of choice.
(from Joerg)
Here are the specifications of the tested and running prototype.
Specification of RS232EEG_01 (date:010502)
----------------------------
isolated power supply:
* input voltage: 7..12V dc, or 5V dc stabilized (from
PC or mains adaptor)
* isolated with DCDC-converter(TMA0505S):
Isolation voltage Input/Output 1'000 VDC
Isolation capacity Input/Output 60 pF typ.
Isolation resistance Input/Output >1'000 Mohm
isolated RS232 Data-lines (opto-isolated)
* 2x 6N139 (RxD, TxD)
Viso > 2500 Vrms (Input-Output Momentary
Withstand Voltage)
Resistance (Input-Output) Rio=10^12 ohm
Capacitance (Input-Output) Cio=0.6 pF
Microcontroller:
* Atmel AVR AT90S4433 at 7.3728Mhz
with 6 channel (multiplexed) 10 bit resolution ADC
EEG-amplifier:
* 2 channels
* about 100uVpp input range (adjustable)
* lower corner frequency: 0.25Hz
* upper corner frequency: 33.1Hz
* -3dB bandwidth: 32.9Hz
* noise: about 1uVpp over above specified bandwidth
* common-mode rejection: typ. 115dB
* Impedance, Differential 10^10ohm || 22nF
* Impedance, Common-Mode 10^10ohm || 60pF
misc.:
* 256Hz samplefrequency, (optional 200 Hz)
* 4 unused ADC-channels (input range +-2V)
* 4 TTL-inputs (for switches e.g. for marking events
by the user)
* 4 LED-driver outputs (e.g. for light goggles)
* 1 PWM output
* hardware UART (RS232 transmission
parameters are: 1 startbit, 8 data bits, 1 stopbit,
no parity, 57600 baud)
* on board calibration generator: 50uVpp 10Hz
rectangle wave
* easy in system programmable uC-EEPROM/Flashrom
* uC-firmware written in AVR-GNU-C
At the moment communication direction is only from
Atmel-processor to PC.
The hardware however supports full duplex communication. This
feature will be used in later firmware releases to support the
PWM-output and LED-Goggles.
---------------------
Joerg's comment: "Or did you want the specs of the new design ?"
Questions: Who decides which of the two (or both?) is going to be
further developed?
Has the soundcard idea been put aside as non-functional?
---------------------
There is interest and discussion of getting FDA approval
of the unit as a medical device.
---------------------
There is interest and discussion of the unit being available
as a manufactured product vs a "kit".
---------------------
The parts list which I can read but appears not yet complete
shows a parts cost of $DM 165 or about $US 75 thus far.
---------------------
Host computer requirements: (help?)
| Unfounded guess is any pentium class machine capable of
| running W95 or later; unless Rob Sack's software requires
| more horsepower than that. (Rob?)
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:29 BST