Alt-BEAM Archive
Message #07581
To: beam@sgiblab.sgi.com
From: "Sean Fox" seanjamesfox@hotmail.com
Date: Thu, 11 Nov 1999 15:07:23 PST
Subject: [alt-beam] Competition
Ok I am thinking about starting a robot wars competition in BC i fanyone
lives in BC and would like to help me with the project and help me make a
web page email me at
seanjamesfox@hotmail.com
Ok thanks for your help
Sean
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7582 Thu, 11 Nov 1999 15:22:57 -0800 [alt-beam] Heads that go in circles beam@sgiblab.sgi.com Bruce Robinson Here's a mechanical tip for those of you who have done everything right
electronically, but still can't get that head to stay focussed on the
light.
If your photocells/photodiodes are exactly parallel, the amount of light
striking them will be approximately the same, even when they turn away
from the light. This means they might tend to drift due to very slight
differences in the elecctronic balance of your circuit.
There's a couple of things you can do to make your head more
directionally sensitive:
1) Mount the photocells/diodes fairly close to each other, and mount a
thin opaque divider between them, projecting forward. When the head
turns away from the light, the divider will cast a shadow on one of the
photocells, making a large difference between the two sides of the
circuit.
2) Mount the photodevices pointing at an angle away from each other.
When the head turns away from the light source, one photodevice will
receive light more directly (i.e. light strikes closer to
perpendicular), and the other device will receive light less directly
(i.e. light becomes closer to parallel).
3) Also, in a brightly lit room the ambient light may overwhelm the
small differences between the photodevices. An opaque shade just above
the photocells will reduce this effect considerably. You can experiment
with a bit of cardboard to see how far to extend the shade.
I recently combined all 3 ideas by drilling out a gray plastic block. I
cut two sides at an angle, then countersunk 1/2" holes in the two angled
faces to hold my photocells. I drilled 1/8" holes at the bottom of the
bigger holes to thread the photocell leads through, and then I drilled a
1/4" hole through the back to line up with the 1/8" holes. The plastic
was a chunk of ABS picked up from the waste bin of the local plastic fab
shop. Finished size is about 1" x 1-1/4" x 3/4".
The attached (very small) GIF file should give you an idea what I'm
talking about. I show an angle of 41 degrees for the angle of the face
-- that's half of the tip angle on the countersink I used. If you use a
regular 1/2" drill, the angle would be 59 degrees, but I wouldn't worry
too much about this. 45 degrees should work fine.
Regards,
Bruce
7583 Thu, 11 Nov 1999 15:44:32 -0800 (PST) [alt-beam] Colony beam@sgiblab.sgi.com Daniel Grace I just got into BEAM, and I remember a long time ago I
saw a BEAM site about a colony of bots that
'communicated' with eachother. That is pretty much all
I remember. I don't know to what level they worked
together or anything, just that there was some. Has
anyone seen something like this, or done this? Any web
pages you can point me towards? I want to do something
like this of my own, but need some ideas.
~Daniel
=====
ICQ # 39402143
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Bid and sell for free at http://auctions.yahoo.com
7584 Thu, 11 Nov 1999 18:47:31 EST [alt-beam] Re: Colony beam@sgiblab.sgi.com JVernonM@aol.com In a message dated 11/11/99 6:26:02 PM Eastern Standard Time,
lifebytes_98@yahoo.com writes:
> I just got into BEAM, and I remember a long time ago I
> saw a BEAM site about a colony of bots that
> 'communicated' with eachother. That is pretty much all
> I remember. I don't know to what level they worked
> together or anything, just that there was some. Has
> anyone seen something like this, or done this? Any web
> pages you can point me towards? I want to do something
> like this of my own, but need some ideas.
>
Hi Daniel,
If colonies are your bag then check out Craig Maynard's Cybugs. They are the
only BEAM colony bots that are out there. They work extremely well, and the
hunger and predator-prey boards are really something. Very affordable as well.
See ya,
Jim
http://www.geocities.com/SoHo/Exhibit/8281/beamart.html
7585 Thu, 11 Nov 1999 16:52:42 -0700 [alt-beam] Re: Heads that go in circles Ian Hi
> The attached (very small) GIF file should give you an idea what I'm
> talking about.
Damn that is small. So small in fact that it isn't even there =) Anyway, got
to go finish that order to digikey.
Laterz
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