From: Doug Sutherland (wearable_at_earthlink.net)
Date: 2002-01-14 19:47:25
Hi Jim,
I am also from the school of "build and test". You can spend
a lot of time designing, but if you don't actually try it in
use, the design might not be workable for many reasons. I'm
a software guy primarily, but I do hardware stuff too, and I
always shoot for "vertical prototypes" that can demonstrate
that things work end-to-end before refining any hardware or
software.
I held back on my digikey order of parts when I heard that
the ModularEEG wasn't performing very well. Since then you
posted your schematics (thanks!) and also Andreas posted
even more schematics. Now I am really confused! I have no
idea which of these circuits to try. I like this TinyEEG
approach a LOT (for size/mobility reasons), although I think
it would be good to have at least some expansion capability
to add more modules. I wonder if that same design could be
done with the AT90 series uC on the same form factor.
Regarding microcontroller choices, I think Atmel is a much
better choice than HC11. The specs are very impressive. It
is getting hard to find HC11 chips too. The microcontroller
in ModularEEG is $6.45, and I can make my own programming
cable and download free dev tools. I like how small they
are too. Your comments on A/D resolution are interesting.
I wonder if there are Atmel uCs with 12-bit ADC? Is there
a concern with conversion time when you go to 16+ bits?
I am waiting for you hardware folks to tell me that one of
these designs is ready for building. Then I will work on
some software.
-- Doug
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:36 BST