Alt-BEAM Archive
Message #02850
To: Sean Rigter rigter@cafe.net
From: Steven Bolt sbolt@xs4all.nl
Date: Sat, 1 May 1999 15:58:07 +0200 (CEST)
Subject: [alt-beam] Re: Smiley
On Fri, 30 Apr 1999, Sean Rigter wrote:
---8<---
> I guess the higher order logic gates of your earlier designs were
> always considered too digital by some but diode logic used here
> is ok (Hmmm? I wonder if that isn't devolution?)
At least you won't be able to halve the IC-count on this one ;)
I hope Smiley will be a pointer to the use of clocks as gearmotors.
For just $3 you get a good quality, easily available motor which
consumes just 1mA or so at less than 2V. Very nice if you want
cheap micropower mechanics. And as Smiley demonstrates, interesting
behaviour - including a full reverse of the travel direction - *is*
possible with motors that always turn clockwise.
> I wonder if using 3 or 4 Si diodes in series with the 390K could
> replace the transistor/LED?
>
> I figured out the answer is no! The voltage drop for output to input
> connected diodes varies with the cap charge and diode resistively
> becomes progressively higher as the capacitor voltage rises. With your
> transistor, the collector decouples the capacitor voltage from the
> reference LED which is then only sensitive to V+ variations.
Just so. But I'm sure you'll be able to improve on Smiley in some
other way. You've an impressive knack for doodling up pretty little
circuits!
Best,
Steve
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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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