Alt-BEAM Archive
Message #12287
To: beam@sgiblab.sgi.com
From: CORBIT GIBERSON aethelwulf@home.com
Date: Tue, 21 Mar 2000 14:23:17 -0600
Subject: [alt-beam] Re: Question about vibra-popper mechanics
> In a message dated 3/20/00 7:02:08 AM Eastern Standard Time,
> ben@wollongong.apana.org.au writes:
>
> > No matter which direction I make the motors spin, the bot gets pushed
> > backwards when a motor fires.
Why not put the "eyes" on the back then. switch wich is front and wich
is back.
12288 Wed, 22 Mar 2000 07:45:15 +1100 (EST) [alt-beam] Re: It works! beam@sgiblab.sgi.com Ben Hitchcock Hi,
> So, this circuit is basically FRED with the motors not touching the ground
> and the pager weights still on? Interesting.
> -William
Actually it's anything but FRED. I used a 74HC14 to generate a 1 Hz
oscillation, and feed that through two LEDs. The other side of each LED
is connected to the input of a latching (for AC) pair of gates. When the
gate latches, it turns on a motor through a BC337 transistor.
It might seem like a strange way of doing things, but I wanted to achieve
some interesting behaviour:
When in a decent pool of light, the circuit will lazily turn on once on
the side that is furthest from the light - similar to a photopopper - and
then wait until it is charged up before attempting another 'pop'. If the
light pool suddenly decreases in intensity, the robot will set off on a
trek towards the nearest light source. But the motors will be firing
constantly when this happens. It means that this robot can 'cross' areas
of deep shadow where there isn't enough light to charge up the cap, so
long as the shadow isn't more than, say, 30 cm across.
I'm never content with using an unmodified circuit!
btw I left FRED under my desk lamp last night for a while, and it locked
up after a while (an hour?). I believe that it's to do with both FLEDs
oscillating at the same frequency, and coupling to each other through the
power supply. This might be just enough to stop it from firing. I'm
working on a solution.
Ben
12289 Tue, 21 Mar 2000 15:02:15 -0600 [alt-beam] Alternative Power beam@sgiblab.sgi.com CORBIT GIBERSON
Any one out there know the power rates of those crystal radio thingys?
The stuff that you can use to both receive the signal and produce power?
I was thinking it may be interesting to try out on a night active bot. I
found some kits for radios that are the size of a credit card, stack a
few of them and the foot print would stay pretty small. Think of it, a
dark seeking little bot that is powered by radio waves( maybe even throw
on one of those luminescent sheets.- fire fly/glow bug)
Do you think it could work??
I cant find the link right now but once I do I'll post it.
Corbit.
12290 Tue, 21 Mar 2000 15:47:52 EST [alt-beam] Re: Caution: newby questions beam@sgiblab.sgi.com BUDSCOTT@aol.com Hi chris,
try www.solarbotics.com, they have kits, but they also have alot of good
solar panels and motors for all kindsa stuff. Also, try hobby stores, or
magazines for hobby servos to use as gear motors, if your lucky you can get
servos as cheap as $9.00 (in my filthy U.S. money, is it just me or does most
currency collect an unusual amount of filth.) Have fun!
-Spencer
12291 Tue, 21 Mar 2000 15:55:25 EST [alt-beam] Re: It works! beam@sgiblab.sgi.com BUDSCOTT@aol.com In a message dated 3/21/00 4:21:52 AM Central Standard Time, beh01@uow.edu.au
writes:
<< Thank you to all who responded to my vibra-popper question.
I turned the LED's (yes, clear-lensed LEDs used as light sensors) around so
that they were pointing towards the motors, not away from them, and
nominated the other side of the robot as the front. If you can't beat 'em,
join 'em I say.
Now this flat little robot is battling it out with FRED for the best place
under the desk lamp on my desk. It takes a while to charge up compared to
FRED, but it sure makes an impressive racket when it does fire!
I wonder why the motors only pull, not push? Aren't physical systems
strange?
Ben >>
Its a twisted science that physics is, it has to do with the direction of
force created by these shifting wieghts. it isn't the direction the motors
will spin, but the way the eccentrics exert their force, up forward down
backward. since the spin around in a complete circle no matter what direction
they spin they'll pull only one way. wierd, and impossible to explain. glad
it works, looks like something really worth tryin!
-Spencer
12292 Sun, 19 Mar 2000 21:03:26 -0500 Re: all powerful light............. Matt
> also art type stores have "real light" bulbs...for artists when they're
> stuck indoors or something...I'm guessing here ....hehe (ok I'm not
> guessing that art stores have them...I know that bit....I guessed the
> bit about what they use them for...anyone know? :-)
>
>
> Matt
>
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