8331A's back indexer thought

because I put the brain and battery on the left and motor on the right side,so there’s no place for those gears onthe out side.
so I put some gears between 2 c-channel and some inside with the back rollers.
after testing I find out that themotor could still speed up to 200rpm and 600rpm,which is a pretty good thing for me .
do you guys have some advice for my back indexer? hope to get your reply!

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what kind of advice are you looking for?


like the disadvantage of this kind of disign,because i can see most of the team dosen’t do the same thing as me.

well I mean if it works well then it’s good. It looks pretty solid.
And poopers are pretty good things to have, so yeah its good.
unless you have any specific problems with it you need help on, that’s about all I can say.


is there any difference between thick and thin rubber bands?

Thick snap less and are really just better for most applications

one is thick, the other is thin. I’d assume the thick ones would be tighter and have a bit more traction because of their thickness. I haven’t used #32 ones for rollers ever, but #64 (thick ones) work just fine so it probably doesn’t matter that much as long as you space the bands well.

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ok, I really appreciate your reply!
I’m asking for reply because the robots disigned by others are too good and I don’t really have confidence on my own robot.
still need to improve meself though.

You should test it if you haven’t already so you can judge for yourself it it’s good enough. A good speed to aim for is to be able to score or discard balls as fast as you can descore them, and to be able to descore/score 3 balls in around 1-2 seconds.

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they’re the same.I think reason why you think they are diffrent is that I stretched it to different lengths.

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Sure. maybe a driving test next week.

what do you mean “Thick snap”?
sorry my English is not very well (I’m not a native speaker)

do you mean less gears is better?

he means that the thick rubber bands snap less often than the thin ones.

less gears is always better because less friction and complexity, but you do need to use gears in this application to reverse the direction of the back rollers. you’re using the minimum number of required gears though you you’re good.

(you could technically do something funky with the chain to reverse the direction by having the chain like mesh against the sprocket instead of around it but that would have a lot of friction so not a good option imo.


As xenon stated thick bands snap less often than thin ones do. This will improve their performance in a competition setting. Generally, thicker rubber bands are the better choice.



thanks to Xenon,now I understand.
yeah,thick one is better,maybe I’ll change the thin rubber band.

oh you mean thicker rubber band diffrently than I use?As they said, thicker one is just better(at least I think so)

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