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DPRG: Rhino arm

Subject: DPRG: Rhino arm
From: Jim Brown brownjim at airmail.net
Date: Mon Aug 16 14:49:10 CDT 1999

>How goes the Rhino arm.   

The program that came with the Rhino arm I never got to
compile quite right since it was written for a different
compiler.  I think I might have sort of gotten it to work,
but because the motors lose steps and other nonsense I 
think it renders the program useless.

I wrote a simple program where the rhino arm can be controlled
by pressing keys on the keyboard.  Arrow left spins it left,
arrow right spins it right, arrow up moves it up, etc.  The
instructions are displayed on the screen.  It's not too hard
to control.  I also thought about taping arrows on the keys
that control the arm to make it more understandable.

I've found however, that the rhino arm is not in that great
of condition.  The C and D motors loose steps and the gripper
gets jammed now and then.  Also when the arm lifts sometimes
it binds a little.  Sometimes you have to turn the controller
box off and on again to get it to respond when it locks up.
I got into the encoders and tweaked a potentiemeter in there
and the C and D motors seem to be working a little more reliably
but still not quite right.

But other than a few glitches like that, I've been able to
get it to work.  I wadded up a few pieces of paper and was
able to control the arm to pick them up and move them around.
I let my wife try it and my daughter try it, and they both
had little trouble getting it do move the paper balls around.
My wife suggested bringing tootsie rolls and letting the
kids try to pick them up and put them in a basket or something
like that.  Definately it will have to be supervised, and
probably restarted now and then and perhaps given a technical
"thump" now and then, but I think most of the kids age 5
and up should be able to do it (maybe age 4 I don't know).
Another suggestion she had was to make paper balls with
messages written inside.  One of the messages might be
"sorry try again" and another message might be "you won a t-shirt"
or "you win an all expenses paid trip to Disney World for a month
with $25,000 spending cash".  :>  Uh, yeah, but except
for that last swirling brain spew, the t-shirt winning
thing might be fun.

Currently, I'm trying to see if I can kludge or figure out
a workaround for some of the problems.  Even if I can't, I
think it'll be ok for the pepsi-kid-around.

I think Barry was a little concerned with leaving the arm
at the pepsi-kid-around overnight.  We may want to schedule
people to take it home at night and bring it back in the
morning, along with some other stuff like computers we
may have up there.

Overall, the arm is pretty cool, and I've had fun playing with it.
I think we might have a mess of kids wanting to try it.

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jim_brown at bigfoot.com jbrown at dprg.org http://www.cyberramp.net/~jbrown
Cole's Law:  Thinly Shreaded Cabbage


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