Alt-BEAM Archive

Message #05765



To: alt-beam@egroups.com
From: BSkater12@aol.com
Date: Tue, 17 Aug 1999 21:33:56 EDT
Subject: [alt-beam] DigiKey


Why are part P241-nd (The 1.3V Solar cells) so cheap. Is there something
wrong about them? There are only 1.76 for 1 and for then there are only 16.00
bucks for 10! I am new to BEAM and I am not sure about the prices of things.
So is this normal?

BSkater12



5766 Wed, 18 Aug 1999 12:08:11 +1000 (EST) [alt-beam] Re: Contest entry (the bounty bot) beam@corp.sgi.com (mailing list) Benjamin Edward Hitchcock ----- Forwarded message from Bruce Robinson -----


And if he got 2 entries, he might very well award a prize to a plain old
bot, just to teach the rest of you a lesson. I wonder how many people
with moderately different ideas didn't enter because they thought the
"big guns" would outshine them. I wonder how many of them are kicking
themselves now.

---

I made a solar powered robot similar to LEM about 5 months ago, and wrote
to Steven Bolt about it. I was going to enter it into the competition,
but I took one look at that 'manta ray' idea with a SE and a flexible body
that swims around a swimming pool by ingesting and exp-elling water, and I
gave up completely.
It was just too much effort to set up a tripod, take 32 Quicktake images,
download them all, turn them into a movie, write reams of documentation,
all for the sake of a last place in a competition dominated by manta ray
bots!

I WAS kicking myself after I saw LEM. That was my idea! (Well, of course
it wasn't, butI did come up with it independantly). I designed my own SE
for it, based loosely on a combination of the Alf circuit and a
photopopper-style SE. It's sitting on my shelf now, covered in four
months worth of dust.

I did find that with a SE-style LEM, it is better to only fire one motor,
rather than two. Maybe this was to do with the amount of power in my
0.047 uF cap driving pager motors, but anyway, firing two motors doesn't
work nearly as well as firing one motor.

IF anyone's interested, I'll post some pictures.

Ben



5767 Tue, 17 Aug 1999 22:57:12 -0400 [alt-beam] Re: Contest entry (the bounty bot) beam@sgiblab.sgi.com Bob Shannon

Benjamin Edward Hitchcock wrote:



>
> I WAS kicking myself after I saw LEM. That was my idea! (Well, of course
> it wasn't, butI did come up with it independantly). I designed my own SE
> for it, based loosely on a combination of the Alf circuit and a
> photopopper-style SE. It's sitting on my shelf now, covered in four
> months worth of dust.
>
> I did find that with a SE-style LEM, it is better to only fire one motor,
> rather than two. Maybe this was to do with the amount of power in my
> 0.047 uF cap driving pager motors, but anyway, firing two motors doesn't
> work nearly as well as firing one motor.
>
> IF anyone's interested, I'll post some pictures.
>
> Ben

I'd love to see some pictures.

On LEM, if I only fire one motor, the ratio of current drawn to motion
generated
drops very fast. To move like LEM, you need more than one motor to produce
rotational
inertia, then reverse one before the other to convert this into low friction
linear motion
by skipping over the surface just a little.

I dont think that can be done with one motor, but I'd love to be wrong!


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