Alt-BEAM Archive

Message #11785



To: beam@corp.sgi.com
From: Justin JAF60@student.canterbury.ac.nz
Date: Wed, 15 Mar 2000 02:52:52 +1300
Subject: [alt-beam] Re: mini motors


> I've seen Fang's treaded beast, but I'm working on something a lot
> smaller/lighter...Has anyone else tackled the tread problem in a tiny bot?
> Looking at microvore sizes in the near future.

I'm looking into it, and believe it or not, some of the best looking
stuff I've seen is some lego parts. Lego isn't cheap, but it's an
unlimited supply of parts that are available for ever and ever. Unlike
certain excellent gearmotors we could name :-)

Part 5119 - ultra miniature gearmotors (not much more than 1x1x1cm).
Never used them, but someone on the list played with some a while back
and was quite impressed with the efficiency. NZ$30 each (approx US$16)
Part 5278 - chain links x35 (ie miniature caterpillar tracks, about 5mm
wide) very close to that MIT "Ant" look.. NZ$9.50 (approx US$5). You
might need two sets if your tracks are long.
Part 5229 - Assorted gears that mesh with the above tracks. Add a paper
hubcap, spray-paint them silver or black, and no-one will ever know
you're using lego :-) Additional bonus - they slot right onto the
gearmotors. NZ$11.50 (approx US$6)

Costly, but I figure this is more than offset by the construction hours
saved. (And that MIT "Ant" look is pretty cool :-)



11786 Wed, 15 Mar 2000 02:52:56 +1300 [alt-beam] Re: Yet another SE question beam@corp.sgi.com Justin >Could it be that the cap never reaches the 2.7 volt trigger of the 1381?

Possibly. I don't know much about caps, but try replacing the solar cell
with a couple of batteries (ie a 3V source). Chances are it will go. My
suspicion is that in order to reach the 2.7V trigger, you have to
overcharge the cap (rated at 2.5V), and above 2.5V the cap starts
leaking some of the charge. If you're running from batteries, the leak
is too small to stop things, but using a solar cell, the amount of power
is so small that it leaks faster than it charges.

This is a guess. There are people here who know twenty times more about
caps than I do. I reserve the right to be wrong :-)



11787 Wed, 15 Mar 2000 02:52:58 +1300 [alt-beam] Miniature video transmitter? beam@corp.sgi.com Justin Given that CCD video cameras are so small, cheap, and power efficient,
they're just begging for beam application. I know there was a thread a
while ago about interfacing them to the core, but I was wondering about
video transmission (I have one that outputs a normal video signal). I
got some FM transmitter circuits that have quite a range and are very
power efficient, and was thinking that something similar transmitting
the signal from the camera could make for a nice Mars Explorer style bot
that fits in your hand :-)

Unfortunately, of all areas of technology and electronics, radio
interests me the least, thus I know virtually nothing about it. If
someone knows and has the time to post (I don't have the time to
research right now) what kind of frequency is needed for video
transmission? Could FM transmitters manage it, given that the small CCD
video signals are a quarter of broadcast resolution. Is the resolution
relevant to frequency?
I've had a look for existing circuits, but there don't seem to be many
beam-friendly ones - either really bulky, or designed to only reach from
one side of your room to the other to eliminate cords. I found some
commercial spy-shop ones that were bang on - tiny things, small aerials,
good range, but they were assembled products you could buy, not the
circuits...



11788 Wed, 15 Mar 2000 01:35:58 +1100 [alt-beam] Re: Re:Interesting, ain't it? beam@sgiblab.sgi.com void_s@ihug.com.au (Xaphiosis) I read it too and have now been alive for 18 years ...
it was a good story though...

X.

>Make that at least three people on the list, but are all of the three
>over thirty?
>
>Regards,
>Dave

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