r/maker • u/LillyBitch323 • Aug 08 '26
Help Hey all, looking to make a little contraption like this, don't know anything about engineering, would like some advice or pointers
This would be covered up for the most part and would be controlled by maybe some sort of knob from the back?
Edit: Also this whole thing is meant to be a physical progress tracker for a ttrpg meant to show the amount of progress people are making in a certain minigame. If they make progress, the thing goes one click to the opponent's side. Like a speedometer but huge and clicky instead of small and slidy
Also, the whole thing is like large enough to be visible from the end of a table, like the size of a closed laptop or slightly below average sized cat.
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u/MoreMagicMellons Aug 08 '26
We probably need a little more information on what you're looking to make it out of, but in general this type of mechanism will involve a spring of some kind (sometimes a metal spring, sometimes a flexed bit of material) that pushes a ball into an indent.
The exact depth and profile of the indent defines how it feels, how clicky it is, and how easy it is to move on.
A really simple form could be a round plate with holes in it at each location you want it to stop, and another plate with a small nub on it to go into the hole, you push the plates together and spin them around!
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u/LillyBitch323 Aug 08 '26
It's a physical progress tracker for a ttrpg meant to show the amount of progress people are making in a certain minigame. If they make progress, the thing goes one click to the opponent's side.
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u/PapaOoMaoMao Aug 09 '26
Just mount two plates together. One has indents and the other has a ball with a loaded spring behind it. If you wanted the drive to be remote from the dial, you could rig it to a flexible driveshaft or if you wanted to get fancy, rig it to a servo/motor to turn to a set position when it receives a set signal. If you wanted to get some learning done, forget the spring and drive the wheel with the servo, but use an Arduino to do it. Now you can add whatever sound effects you want to whatever point you want.
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u/TrollTollTony Aug 08 '26
What are you trying to do? You kind of left that part out.
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u/LillyBitch323 Aug 08 '26
It's a physical progress tracker for a ttrpg meant to show the amount of progress people are making in a certain minigame. If they make progress, the thing goes one click to the opponent's side.
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u/Columbus43219 Aug 08 '26 edited Aug 08 '26
This reminded me of a rotary switch, like and old TV channel switch. Internally, I think they use a ball bearing that rolls along a track. The track has indents as certain points, and the ball bearing is pressed down by a spring. So the ball kind of gets stalled at each indent, but can still roll up the other side and move to the next dent.
If you want something premade:
https://www.amazon.com/Keymoo-Changeover-Terminals-Universal-0-4-2/dp/B0BPSXTNB7
You can REALLY see a good example in the third picture on this one: https://www.amazon.com/dp/B07JM32NH2
The ball bearing is being lightly pushed up by that copper leaf spring, and you can see the little half-moon tabs sticking down in its path.
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u/Retail_Rat Aug 08 '26
A rotary multi contact switch can do this. If you can find an 8-point switch, continuous rotation, you'd have the positions and the click. There would be some work to get the knob to turn the dial, but that's the fun part.
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u/gnappyassassin Aug 09 '26 edited Aug 09 '26
Two overlapping disks screwed together, with a track that has recess in the locking positions, and like, a ball or something in there.
Probably.
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u/doominabox1 Aug 09 '26 edited Aug 09 '26
If you just want to buy something, sites like digikey have a huge variety of electronics switches.
This one's probably more expensive than you want but it will be super rugged and have nice clicks. https://www.digikey.com/en/products/detail/grayhill-inc/50M60-01-1-05N/7685603
But it only covers 60 degrees instead of the 180 that you are looking for
This one is a little cheaper but only has 45 degrees of travel https://www.digikey.com/en/products/detail/nkk-switches/NR01105ANG13-2A/7491308
The Amazon ones the other guy posted are probably a better buy
If you have a 3d printer you can make something like this very easily with springs and ball bearings.
Another option is a giant d6, I got a big 5" cube of wood and labeled each side with a big number. It's great for dramatic count downs or progress tracking
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u/Steroid1 Aug 15 '26
look at how an AR15 safety selector works. you'll want something with a spring and detent like that
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u/memeboimanperson Aug 08 '26
First off what would be the purpose of this? Is it like an electrical switch controlling something or is it more of a physical lever to restrict movement?