Worlds thinnest tally counter (proof of concept)

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Maybe this is more interesting for you - it's a prototype of a mechanical calculator based on this design:

https://www.prusaprinters.org/prints/86506-mechanical-calculator-working-prototype

(it jams less and is not as fragile)

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Hello,

as far as I know this is the thinnest mechanical counter in the world (4 mm) that is 3d printed. Chances are good it is the thinnest tally counter in the world. It has the dimensions of a credit card and can count from 0 to 999. It's more a proof of concept than it is actually useful though.

I hope you like it. If it does not work for you please leave a comment or shoot me a message instead of just posting a 1 star review, I'm sure there is no problem that can't be solved.

How does this thing work?

When you press the actuation down, it turns gear 1 by one number. As soon as the actuation is fully pressed down, the retaining mechanism in the cover snaps into gear 1 and prevents it from turning back in the other direction. This allows the actuation to be pulled back up. The actuation is designed to be stable when pressed down against gear 1, but to give way when pulled up.
After the actuation is pulled up, it can be pushed down again to add another number. When you have added 10 numbers, the second gear turns to 1 (=10). If you push the actuation down again 10 times, the second gear turns to 2 (=20) and so on. In the second picture you can see the "display" showing the value "0" "0" "2" which translates to the number 2.

Unfortunately, there is currently no way to reset the counter to 0 (without disassembly). So you can either press the actuation down 999 times to reset it to 0, or think twice before you count something with it...

Although it is just a proof of concept, it actually works. You just have to be a bit careful with it so that it does not jam.

UPDATE 07.11.2021:

I made a few changes to the counter. I didn't delete the old pictures so you can see the difference.
A few things that I have changed:

• the gears now have a proper calculated module and geometry
• the center distances are now properly calculated
• I had to raise the overall height of the gears quite a bit, becuase my prints just were not percice enough to make it work with gears that are only 0.5mm high.
• the overall height increased from 3 mm to 4 mm
• the side is open so that you can see the gears rotate (I will change this in the future)
• I improved the actuation lever
• there are now 10 numbered holes in the cover which act as a display. This solution is a bit unorthodox but it works. You have to mark a dot on the top of the gears that aligns with the holes. This way every time the gear turns a different hole is darker than the other ones. I also added numbers on every hole to make it easier to tell the number. They did not turn out great when I printed them but maybe you are more lucky with your printer setup.

the actuation is now guided on both sides Old version from 05.11.2021:

old Text:

Hello,

this is the thinnest mechanical counter in the world.
So far it can add 1 but cannot yet be reset to 0.
It also lacks any numbers (or windows through which you could see the numbers...). Also the gears don't have a properly calculated modul or anything, it's just a concept at this point.

As you can see, the counter is in a very early stage, but it works.
The difficulty is that the quality of the 3d printed parts is good enough, they must not warp when they cool down.

The counter is the size of a credit card and about 2-3 mm thick. When you push the lever down, the first gear is turned. After 10 turns, the next gear turns, and so on.