From: Doug Sutherland (wearable_at_earthlink.net)
Date: 2001-12-05 05:52:01
Hi Laura,
> Under "design with a minimal number of parts" you link to
> www.biosemi.com while next under "modeled after the Biosemi
> designs" you link to www.biosemi.com/publications/artikel7...
> perhaps these are reversed?
Ooops ... yes I had those URLs all mixed up ... thanks for
pointing that out, it's fixe now.
> You said before that Joerg's design is based on the Biosemi
> design; can someone clue me in to which Biosemi design it is
> based on?
If you look at the schematic for Joerg's amp board for the
new ModularEGG, he includes a URL to the Biosemi article:
http://www.biosemi.com/publications/artikel7.htm
Joerg has clarified this, the Biosemi reference refers only
to the right leg drive. Unlike the Biosemi article Joerg is
using an INA114 instrumentation amp instead of op-amps. He
definitely knows better than I ever will, so I say fine!
I'm looking forward to trying this design out once it has
been verified that it's tested.
> Also, Jim's page states that his firmware supports a 0-60
> Hz frequency range, while your page states he acheived a
> band width of 0.1-100 Hz. Can you clarify this for me?
It sounds like Jim has tried a zillion different tweaks of
his HC11 based system. He told me that he's demonstrated
0.1-100 Hz. I think he has tried lots of different rates
of sampling and configurations of the input stage ...
> The op-amps in the Brainmaster look like they would cost
> about $10, but it's hard to tell because they are only
> sold from digikey in units of 100 or more.
It looks like Digikey isn't really a supplier of Analog
Devices parts. They list zero inventory of AD620. You can
buy parts direct from Analog Devices but you have to
register with them. In fact they often give free samples,
but you need a company/project to stand behind. They
used to send me free samples all the time when I worked
for Sun Microsystems. You could try calling yourself a
consultant and describing a project to design some med
device protos, it might work. Don't tell them you are
a hobbyist, tell them you are working with a client ...
Newark has AD620s and OP90s ...
http://www.newark.com/psearch/searchResults.jsp?action=0&First=0&QText=AD620
http://www.newark.com/psearch/searchResults.jsp?action=0&First=0&QText=OP90
There are also 68HC11 boards that can be used in place
of the obsolete 68HC11EVBU at at Axiom and NewMicros:
http://www.axman.com/Pages/neuprod8main.html#68hc11
http://www.newmicros.com/
I have some of these MIT handy boards, I'm going to try these
out and see if I can load Jim's firmware:
http://lcs.www.media.mit.edu/groups/el/projects/handy-board/
http://www.gleasonresearch.com/
I made these handy boards walk across the room on six legs.
Maybe I can also use them to capture brain waves. Maybe I
can make the brain waves control the walking of a bot. Okay
bzzzzt back to reality doug :)
-- Doug
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:32 BST