Subject:
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Re: The Great Ball Contraption
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Newsgroups:
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lugnet.robotics
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Date:
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Sun, 9 Jan 2005 22:09:09 GMT
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Viewed:
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5472 times
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In lugnet.robotics, Russell Nelson <nelson@crynwr.com> wrote:
> Steve Baker writes:
> > Another thought I had was that the organisers might want to consider
> > building a stage that has one input hopper and TWO outputs that sends
> > balls alternately to the two places.
>
> Yes! Since the soccer and basket balls are the same physical size,
> there is no reason why a module can't work with both. There is also
> no reason why a module couldn't sort soccer balls out one side, and
> basketballs out another.
>
> To that end, you need a specification for a "Y" module, which has two
> output faces. Also for a module which has two input faces! And a
> module which is a 90-turning corner and a 270-turning corner. It's
> pretty obvious what's needed for them; it just needs to be written down.
I made a device that sends balls alternately down two chutes.
Balls enter through a 2x2 hole in the top, onto the centre of a 7L studless
beam, set up as a see-saw.
Which ever way a ball goes, it drops onto another, longer, see-saw that tilts
the first see-saw the other way to send the next ball down the other chute.
Balls exit though 2x2 holes in the bottom at each side.
I used two more studless beams (liftarms work well too) crossed over to do the
reversing links between the see-saws.
This contraption is about 13 bricks high and 4L deep, but could be made smaller
in height. Its advantage it that it doesn't need a motor. The minimum height
is dictated by the need for the energy from a ball dropping nto the lower
see-saw being more than enough to tilt both see-saws.
Of course this device won't sort balls by colour, but that's a slow process.
Also, soccer balls have black and white bits so you can't predict which bit a
light sensor will see, and hence whether the reading from a soccer ball will be
greater or less than the reading from a basketball.
I used the see-saw device with a vertical ball lifter, based on transmission
chain with a few track links. It was possible to over-run the see-saw device
with too many balls, so that two went the same way, but the through-put had to
be quite fast before that happened.
A module with 2 input faces would probably be a hopper with 2 chutes entering
it. The greatest problem I've had with ball contraptions is balls clogging in
the hopper - sometimes you need an agitator like they use in factories.
Mark
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Message has 1 Reply:
 | | Re: TGBC - The Weakest Link?
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| (...) Any operation involving a long sequence of events as in The Great Ball Contraption (TGBC) is likely to be fouled up by failure of one of the events in the chain - the so called weakest link. Is there allowance for the fact that one of the (...) (20 years ago, 9-Jan-05, to lugnet.robotics)
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Message is in Reply To:
| | Re: The Great Ball Contraption
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| Steve Baker writes: > Another thought I had was that the organisers might want to consider > building a stage that has one input hopper and TWO outputs that sends > balls alternately to the two places. Yes! Since the soccer and basket balls are the (...) (20 years ago, 9-Jan-05, to lugnet.robotics)
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