Alt-BEAM Archive
Message #13908
To: alt-beam@yahoogroups.com
From: Jean auBois hogfather@earthlink.net
Date: Tue, 07 Aug 2001 22:23:07 -0600
Subject: A comment about the Discovery Channel Canada M Tilden Interview
I think there are fairly good reasons why I'm the BEAM Heretic... for
example, in the clip indicated, Tilden claims that the Walkman controller
has 12 transistors. Even superficially this isn't true because he is using
integrated circuits with lots and lots of transistors in them for the
controller. Way more than 12.
So... someone out there might say that, if you weren't allowed to use
integrated circuits, that perhaps the "theoretical minimum" is twelve
transistors. That doesn't work out very well either.
Back in the middle of April Tom Mairs, Bruce Robinson, Eric Seale and I had
a side conversation called "AUUUGHHHH!!!! (was: all transistor
walker)". We were trying to figure out what the _practical_ minimum of
transistors it would be given the Walkman's design: this including Schmitt
triggers for the Nv/Nu elements, sensors, four leg motors, a waist motor,
and so forth. It literally almost became a contest -- whoever could do it
with the smallest parts count in the controller would have won.
Unfortunately, Tom pretty well killed things with:
>I found Wilf's Schmitt inverter article. One BEAMable device = 3
>transistors, 3 diodes, and 8 resistors. Using the Walkman schematic and
>using 6-transistor H-bridges, that would work out to 30 driver
>transistors, 12 microcore transistors, and 6 Nu transistors for a count
>of 48.
>
>I can't tell from looking at the few photos of Walkman, but from the
>schematic it looks like it has 5 motors -- 4 legs and a waist.
I think that Mark is doing great things but when he exaggerates by a factor
of four and _never_changes_his_tune_ (e.g. I heard him saying the same sort
of stuff at the LANL workshop this spring) it leads me down that nasty old
Heretical Highway.
JaB
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