Marble binary tower

by evgiz0r Oct 19, 2018
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An interesting concept for sure, thanks for sharing!

I'm having a hard time getting it to work reliably though...using 8 mm (instead of your 9.5 mm) steel balls, I tried scaling it down exactly proportional to ball diameter (84%) - problem is that, while it works ok quite often, balls will "fall thru" occasionally instead of locking into an open binary position. Seems that the ball is bouncing back too far after it hits the arched stopper, thus continuing to fall down to the next level.

At 90% scale, the balls won't lock at all.

At 80% scale, reliability seems to improve a tiny bit (I'm not really sure), but the balls now tend to stick at the "overflow path" sometimes already (especially when holding the level pieces together - did you glue them?) so further scale reduction might not help much.

Any ideas? Does it work really reliable with 9.5 mm balls?

Kind regards

Hey man, Thanks for sharing

You are right, the vibrations of this model do cause the balls to go through sometimes.
In my prints it was about 20% of balls going through, which is a little annoying, especially on higher towers.
I have tried various changes but i could not make it completely reliable with this gravity and hole mechanism.

I am designing something with two moving parts but it might take a while to be ready.
If you have some idea how to make this specific mechanism work better i would be happy hear.

Sorry for the somewhat wasted time!

Hi, thanks for your information... no, definitely not wasted time, I enjoyed toying around and I'm still contemplating if there wouldn't be a way to improve the reliabilty of this very charming idea!

I guess the key would be to consume more of the kinetic energy of the ball when it hits the (somewhat flexible?) "stopper arch" so it would not bounce back too far and continue to fall to the next level. Of course this locking of the ball is easier with moving mechanical parts (as shown by several other designs here on Thingiverse and elsewhere) but the interesting thing is to do it without :-)

Probably you might want to share your design in some CAD format so it would be easier to modify & experiment?

You can download the design here - https://a360.co/2RZzyqb

Some slight changes but it is almost the same.
Slightly messy workspace but you would have to forgive me :)

Doing something bouncy for the ball to fall is a really cool idea!
I spent some time thinking how to slow the ball, but not making it jump too much or keeping it easily printable.

Thanks... looks nice! Yes, I think the main points would be one or both of

  • slowing down the ball to some kind of "calibrated" (and fairly constant) speed before it hits the stopper, so the stopper flexibility and length & slope of the ramp can be adapted to work reliabily for exactly this speed.

  • invent something "un-bouncey" for the stopper (so the bouncing back will be reduced), making it more tolerant for varying ball speeds. Maybe a kind of shock absorber or other energy reducing material, but a) the space is very limited because the front of the ball has to remain accessible for the overflow phase and b) the fun is to do without any moving parts :-)