Alt-BEAM Archive

Message #12354



To: beam@sgiblab.sgi.com
From: Bruce Robinson Bruce_Robinson@telus.net
Date: Wed, 22 Mar 2000 17:48:45 -0800
Subject: [alt-beam] Re: "Living Machines" question & an experiment


Pat Wehren wrote:
>
> The paper says that if the times of the neurons are roughly the
> same, they will converge on 100100. I can't for the life of me
> see why.

Who says there's no feedback/implex? Well, I did once.

OK, I decided to test out this assertion as follows. I set up and ran,
not one, but two 6Nv loops, completely independent except for a share
power supply (6 V battery). Decoupling caps all over the place, no
floating inputs, everything "by the book".

I first selected components that had as nearly identical values as
possible (helps when you buy resistors and caps by the hundred). Then I
set up indicator LED's in two lines of 6, each line driven by a separate
Nv loop, and ran one impulse around each loop just to check that the
timing was close for all the Nv's. I could watch the two impulses
marching along their respective rows, and by fiddling with the phase
shift, I was able to cross-compare the delay times for all the Nv's.

Having satisfied myself that the times were, in fact, "roughly the
same", I rearranged the LED's so each loop had them set up in two rows
of three, with the LED's for each loop physically separate (to aid
observation). Then I introduced two impulses into each loop in a 101000
configuration, and let them run. The two rows of three made it easy to
observe the pattern: in a 101000 configuration the impulses would appear
at opposite ends of a row of three, whereas in a 100100 configuration
they would march in lock-step down the two rows.

What I found after about 6 hours was that both circuits had evolved to a
1-0-3/4-1/4-0-0 pattern. In other words, the leading impulse would move
ahead just a little before the trailing impulse.

Twentyfour hours later, the pattern had not changed. So for the heck of
it, without disturbing or interupting the pattern in any way, I plugged
a low current gearmotor (10 mA) directly into one pair of adjacent Nv's
on ONE of the loops. This completely disrupted the pattern in the
affected loop ... it reverted back to the saturated state (101010)
immediately. As I had not put any kind of capacitor across the motor
leads, this almost certainly injected a lot of noise into the chip.

But what was fascinating was what happened to the other loop. Mounted on
a separate breadboard, but sharing the same power supply. In about 4
forward-reverse cycles of the motor, the second loop shifted to a 100100
pattern. Just like that, perfect synch, no overlapping. And it is still
doing that, an hour later.

So a noisy, low-current motor hooked directly to the Nv outputs in one
loop affected the impulse pattern in an independent loop, with the only
connection between them being the supply lines. Fascinating.

Bruce



12355 Wed, 22 Mar 2000 19:37:38 -0600 [alt-beam] Re: Schematic index beam@sgiblab.sgi.com Richard Piotter Yeah, My first microcore worked, first time, and it was also my first
BEAM creation. Infact, I still find myself messing up solar engine based
circuits! Hehe!!!


Bruce Robinson wrote:
>
> Richard Caudle wrote:
> >
> > I think that the biggest reason that the 'classic' uCORE
> > is missing is because it dosen't work very well! Too buggy
> > for newbies (and oldbies like).
>
> Nonsense! You've been hanging out with your solar 'bots too long,
> Richard. They're starting to brainwash you :)
>
> Yes, it does take time to get the adjustments just right on the first
> one, but that is just as true of the bicore circuits. Once you've done
> one, the rest are much easier.
>
> Bruce

--


Richard Piotter The Richfiles Robotics & TI web page:
richfile@rconnect.com http://richfiles.calc.org

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12356 Thu, 23 Mar 2000 13:05:44 +1000 [alt-beam] Beam Motors beam@corp.sgi.com lee02@eastloddp12.vic.edu.au Good Day,
I'm just enquiring about a method of operating legs on a beam walker. Geared motors are not available here in Australia, and geararray's are way expensive, I have hobby motors which are known to not have themselves, maybe a rubber band joined to the shaft and to the legs, that work?? or another suggestion?? Thanks to any correspondance.
Timothy
---
lee02@eastloddp12.vic.edu.au
http://www.eastloddp12.vic.edu.au/



12357 Wed, 22 Mar 2000 21:16:21 -0500 [alt-beam] Re: Schematic index "Richard Caudle" > You've been hanging out with your solar 'bots too long, Richard. They're
>starting to brainwash you :)

You wouldn't be the first person to say that I've been out in the sun too
long!
:)

Richard

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