Alt-BEAM Archive
Message #07799
To: beam@corp.sgi.com (mailing list)
From: Benjamin Edward Hitchcock beh01@uow.edu.au
Date: Thu, 18 Nov 1999 08:21:56 +1100 (EST)
Subject: [alt-beam] Re: analog memory
----- Forwarded message from Michael Hirtle -----
what exactly is analog memory and how do i make something like that?
And how do i make an analog timer for a bot?
------------------------------------------------------------------------
Analog memory is just remembering an analog value. You can make a very
simple analog 'memory' circuit using just a capacitor - the voltage after
a few seconds will be the same as what you put into it, providing you
don't have anything 'leaking' charge away. Digital memory as I understand
it is much the same: you just fill the capacitors you want filled, and
every so often you come along again and give the filled ones a 'top up' to
keep their charge levels high.
You can do this by putting a cap across a 1.5 volt battery. (Remember the
polarity!) Measure the voltage, then try again ten seconds later. The
only problem with this method is that in measuring the voltage, you are
actually draining charge off the cap!
For short term memory (say less than ten seconds or so) this approach
works fine but for longer term memory you need something else such as a
mechanical setup, or even use an analog/digital converter and store the
digital signal.
You probably have already used an analog timer for a robot. Have you made
a microcore? Each 'neuron' consists of a resistor and a capacitor, which
is the basis of just about every electronic analog timer ever made. You
can experiment with different R * C values to igve you different times.
In the olden days before programmable logic controllers, when all
automation was done with relays, people used to use pneumatic timers to
set the delays needed for automation. THese consisted of a bellows and a
small air-hole htat you could adjust. After the relay turned on, the
bellows would take a while to deflate - making a crude but effective delay
relay.
We still use them around the place here at the steelworks where I work.
Hope this helps!
Ben
7800 Wed, 17 Nov 1999 13:27:55 PST [alt-beam] Re: absorbpsion circuit or something beam@sgiblab.sgi.com "Timothy Flytcher" >they showed
>this lab where they had hooked up something to this woman and used it
>instead of the mouse, and she could actually move the cursor by thinking
>about it. If it didn't work, she said that getting angry didn't help, so it
>was difficult to stay calm.
there is or was a company in Santa Barbara CA that manufactures them... I
have seen a video game using this technology... But I have yet to see a
wheel chair equipped with one(that's what their design was for)
______________________________________________________
7801 Wed, 17 Nov 1999 13:38:20 PST [alt-beam] Re: More PCB etching beam@sgiblab.sgi.com "Timothy Flytcher" Sorry Thomas,
I have no experience with this... I have seen photo etching using this kinda
technique...
>would you happen to have any experience
>in laserprinting a cirquit onto transparencies and then iron them onto
>the copper? At first glance it seems to be a pretty good solution too.
>
>Hows about dunkin' danish? :)
>
Works for me :)
Timothy...
California, USA
______________________________________________________
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7802 Wed, 17 Nov 1999 17:44:07 -0400 [alt-beam] Re: analog memory alt-beam@egroups.com michael.hirtle@ns.sympatico.ca (Michael Hirtle) >
>
> Hope this helps!
> Ben
I helped a lot, thanks!!!! :-)
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