Alt-BEAM Archive

Message #12299



To: beam@sgiblab.sgi.com
From: Bruce Robinson Bruce_Robinson@telus.net
Date: Tue, 21 Mar 2000 14:44:06 -0800
Subject: [alt-beam] Re: Caution: newby questions


Korus wrote:
>
> Well, I guess the best place to start off with for schematics,
> if you know something about electronics, would be the BEAM Robotics
> tech...
> (http://people.ne.mediaone.net/bushbo/beam/main.html), although
> the site seems to be down right now...

BEAM Tek goes down late in each month, probably due to some sort of
traffic limit imposed by the ISP. There is a mirror of this site at Beam
Heretics, and that's hardly ever down:

http://www.serve.com/heretics/

> Another good place to see would be http://www.beam-online.com/

And after you get an idea of what sort of thing you'd like to start
with, the BEAM Web Index will point you to various pages for specific
types of robots. Caution: this is NOT a good site for surfing ... better
for research once something has caught your fancy.

http://www3.telus.net/rfws/bwi/

Bruce



12300 Tue, 21 Mar 2000 14:44:14 -0800 [alt-beam] Re: Aesthetics beam@sgiblab.sgi.com Bruce Robinson Laura Malinowski Laura/Rob Malinowski wrote:
>
> Is it base material on both sides or a solder mask?

It's a laminate. Copper (?) traces in the center, base material on both
sides. Total thickness = 0.006". Stiff, but flexible, transluscent
reddish brown.

Bruce



12301 Tue, 21 Mar 2000 15:04:18 -0800 [alt-beam] Re: Schmitt inverters? beam@sgiblab.sgi.com Bruce Robinson Justin wrote:
>
> As someone whose understanding of logic gates is derived mostly from
> formal logic rather than electronics, I don't know the difference
> between a schmitt inverter and an inverter.

The Schmitt inverter has hysteresis. In other words, the rising input
voltage at which the output toggles is guaranteed to be higher than the
falling voltage at which the output toggles.

With a slow-rising or slow-falling input (typical BEAM microcore) in a
noisy environment, a conventional inverter could start to toggle on and
off as the input approached the threshold. The Schmitt inverter will
toggle very cleanly. Bicores don't suffer from this problem.

For ordinary logic applications, you can always use a Schmitt inverter
in place of a regular inverter. This is not always the case with
bicores, especially floating bicores.

I see that 74HC240 chips are manufactured in SMT packages. You might
also try a regualr 74HC04 inverter (non-Schmitt) ... I imagine that
would work for a bicore.

Bruce



12302 Tue, 21 Mar 2000 15:20:30 -0800 [alt-beam] conductive epoxy instead of solder? alt-beam@eGroups.com "joe" I was just wondering, would it be possible to put together a solar
engine on a pcb with conductive epoxy instead of soldering the
electrical components together? if not, why? I know it is an odd
question
Thanks

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