At 10:59 AM 6/14/01 -0600, Victor Valdez wrote:
>Is there anybody that can help me to design a pic based interface for a
>brainwave monitor? I need at least a four channel display. It can be for
>pc or gameboy.
>I think a dual channel oscilloscope presented in EPE magazine, based in
>16F877 can help, but I would like to know how to add more channels. In
>Elektor was presented a gameboy based oscilloscope, but I have not read it.
>
>The analog part is easier for me.
>Victor

You have a major amount of isolation work to do for anything like this that
connects to a line powered device.  Serious safety issues.

That being said, you need differential amps for the signals, with wide CMRR.
A browse through national semi' s web page should let you find some good
op-amps to do the job.
The most bandwidth you need is only a few hundred Hz, so you can really
compromise on speed.

Once you have the isolation and analog part worked out, the rest becomes
ADC and output issues.

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differentiate a signature line from the text of an email, I am forbidden to
have it.

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