Subject:
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Re: Crate Size
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Newsgroups:
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lugnet.org.us.smart
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Date:
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Wed, 13 Oct 2004 23:01:19 GMT
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Viewed:
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5340 times
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In lugnet.org.us.smart, Steve Hassenplug wrote:
> Here's a couple more questions for the SMART guys.
>
> First, how many balls are "normally" loaded into a crate? I'm guessing between
> 20 and 30.
>
> How would things be effected if the crates were a little shorter? It appears
> the crates could be one or two bricks shorter, and still handle 20-30 balls.
> Any comments?
>
> If you were to start completely over, would you use the same crates, or would
> you change anything?
>
> Steve
Usually we aim for around 30 balls per crate. That gives enough leeway that if a
robot is out of commission for a few minutes (changing batteries, say) that a
'filling' robot still can run without being stopped. More than around 60 balls
and the crate overflows.
If the crates were shorter then you'd have less margin for error. You'd likely
have to stop any filling robots upstream if a robot goes out of commission
downstream. And any robot that drops balls in from more than just above the
crate edge will start having balls bounce out. Originally we were aiming for
around 50 balls per crate, but the problems made us reduce that number so that
things would work more reliably.
We talked about different mechanisms of lifting crates at one time, which would
have entailed a redesign, but the most reliable way was to grab the top edge of
the crate while also holding it underneath, something which our crates already
did pretty well.
If you design a 'ball contraption', though, I would stay away from crates as a
holding mechanism, and then the height restrictions wouldn't be an issue.
However, to let gravity do it's work, you'll still need to lift balls somewhere
along the line. And that means a mechanism that can get under them. So you're
probably going to want all the balls to be rolling at least two bricks higher
than the baseplate, otherwise you don't have room to lift them. And since that's
your lowest point, you probably want at least five or six bricks higher as a
good minimum starting point. So you're back up to the height of a crate anyway.
One idea for a ball contraption might be to have the output from the previous
module be three or four bricks up. The first thing your module does then, is to
raise the balls to whatever height it needs to do its thing. There's no reason
to raise them any higher than you need then. If you want the balls to roll
through a set of multiple loops, you raise them 40 bricks. If you just want to
shuttle them along, sorting them, say, you can probably get away with lifting
them only two or three bricks higher, and let gravity do the rest of the work
moving the balls around your module.
Back to crates, I think the only reason we would redesign the crates would be if
there were a better set of sensors and/or a better RCX available that would let
us do something with them that we currently couldn't. For instance, determining
what the crate contains.
--
David Schilling
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Message has 1 Reply:
 | | Re: Crate Size
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| (...) If I haven't said this already, let me first express how impressed and fascinated I am with your Contraptions. Three questions about the SMART crate. 1. The one at (URL) is 7 1/3 bricks high. The ones at the Road Show ((URL) appear to be 7 (...) (20 years ago, 19-Oct-04, to lugnet.org.us.smart)
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Message is in Reply To:
| | Re: Crate Size
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| Here's a couple more questions for the SMART guys. First, how many balls are "normally" loaded into a crate? I'm guessing between 20 and 30. How would things be effected if the crates were a little shorter? It appears the crates could be one or two (...) (20 years ago, 13-Oct-04, to lugnet.org.us.smart)
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