Re: [buildcheapeeg] TinyEEG

From: Doug Sutherland (wearable_at_earthlink.net)
Date: 2002-01-07 16:11:14


Andreas,

Now you're speaking my language, the language of tiny,
low power, unobtrusiveness. I want the whole EEG on my
thumbnail, but then I want my whole system on my thumb
nail (freaky thing is: it's getting close).

> fits in less than 1/2 a euro-board. Don't expect the
> through-hole version to be that small.

Sounds awesome, but hard to build.

> It runs on four 1.5V batteries.

Assuming I already have regulated 5V from another
supply (PT6302A) ... can I use that? My battery will
be 12V, powering an embedded PC through 3A 5V
switching regulator.

> I've cut away everything non essential, so forget
> about expandability...

Here's an idea. Leave two pins on the Uc set up for
TTL serial to another uC. A second board can grab
temp, gsr, ekg, emc, and sent data to the other uC
over TTL serial. The first uC just sends the data
down the line to the PC. A simple protocol can show
the data source (do we have this in the protocol in
use now?). The second uC (multi-parameter data
acquisition module) can also accept commands from
the first to set modes etc. A little command language
similar to what GPS receivers use could be set up
to program the modules from the PC. For example you
send an escape code sequence followed by a letter
and number combination. This could set the sampling
rates and other tweaks. I've done this before with
a single microcontroller connected to GPS, humidity,
barometer, and up to 256 1-wire temp sensors. The
PC protocol can be programmed in software, but also
works in a terminal session like hyperterminal or
minicom. Press you escape code, cay CTL-S for the
sampling rate then 300 then a termination char and
the system configures for that rate. The other
channels for temp, gsr, etc can be done the same
way, and can be shut off or on when desired.

-- Doug

PS. Please proto the TinyEEG to make sure it works.
I want this one! I may strugle with making the
board, but it will be worth it.



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