An Unusual Mechanism / Linkage

[Stanleymonkey]

There are the standard cam mechanisms and linkages.

They can be scaled up for large games / stalls for a fair.

Is there a cam / linkage that produces a random movement??

For example - someone turns a handle and some targets bob up and down random amounts making them harder to hit.

 

[Richard_C]

I can't imagine a true random cam in a simple wooden design. You could build the top left one with a very big wheel with a convoluted edge with lots of ups and downs of different depth and duration per rotation. It would still repeat every cycle but be hard to learn unless you observed it for a few revolutions. If you drove that wheel indirectly from another one with either a belt on different diameter wheels or an odd number of gear teeth you would get a lot of hard to predict variations, but still not truly random.

 

[Blockplane]

How about using heavy (possibly steel) balls to trip the 'pop-ups'? with the handle recirculating the balls so they fall down a 'pins on a board'arrangement which would generate a random path.

 

[MusicMan]

A compound or double pendulum has chaotic motion, (https://en.wikipedia.org/wiki/Double_pendulum). You'd have to work out how to put the energy in and how to get it out, electronically would be easiest.

Keith

 

[Dominik Pierog]

https://november.world/Objects-XS-S-M
In simplified version you need 2 gears with uneven tooth ratio.

 

[Stanleymonkey]

I can't imagine a true random cam in a simple wooden design. You could build the top left one with a very big wheel with a convoluted edge with lots of ups and downs of different depth and duration per rotation. It would still repeat every cycle but be hard to learn unless you observed it for a few revolutions. If you drove that wheel indirectly from another one with either a belt on different diameter wheels or an odd number of gear teeth you would get a lot of hard to predict variations, but still not truly random.

Didn't think of meshing some weird gears to drive it as well. That could be a possibility.

 

[Stanleymonkey]

A compound or double pendulum has chaotic motion, (https://en.wikipedia.org/wiki/Double_pendulum). You'd have to work out how to put the energy in and how to get it out, electronically would be easiest.

Keith

Those double pendulums are crazy - but I think converting to some sort of output will be a challenge.

 

[Stanleymonkey]

How about using heavy (possibly steel) balls to trip the 'pop-ups'? with the handle recirculating the balls so they fall down a 'pins on a board'arrangement which would generate a random path.

I can visualise this. Crank becomes something like a marble elevator that you see on a marble run??

 

[TheTiddles]

Generation of “pure” random is a very specialised thing (think cryptography level of special) so just what do you mean by random? Add enough gears you can create a range of ratios, but even an enigma machine can be predicted eventually and your losses for each transmission will be adding up for each one. Doing it mechanically might be less effective than having a few actuators and a simple computer driving them

Aidan

 

[Richard_C]

Raspberry pi springs to mind, but depending on what it's for that might be overkill and needs a different set of skills. Do you need truly random?

Sticking with the mechanical, you could have a variety of interchangeable cams so it never gets too predictable.

 

[Blockplane]

How about using heavy (possibly steel) balls to trip the 'pop-ups'? with the handle recirculating the balls so they fall down a 'pins on a board'arrangement which would generate a random path.

I can visualise this. Crank becomes something like a marble elevator that you see on a marble run??

Yes, that's the sort of thing I had in mind. If the 'cups' or whatever lift the balls back up were unequally spaced, that would add a random element to the timing.

 

[TheTiddles]

How about using heavy (possibly steel) balls to trip the 'pop-ups'? with the handle recirculating the balls so they fall down a 'pins on a board'arrangement which would generate a random path.

I can visualise this. Crank becomes something like a marble elevator that you see on a marble run??

Yes, that's the sort of thing I had in mind. If the 'cups' or whatever lift the balls back up were unequally spaced, that would add a random element to the timing.

How in any way would that be random? Are you perhaps meaning “different”?

 

[Bod]

Title Making Mechanical Marvels in Wood
Author Raymond Levy
Edition illustrated
Publisher Sterling Pub., 1991
ISBN 0806973587, 9780806973586

Might be interesting reading.
I have a copy and all the items I'ved made worked from the drawings.

Bod.

 

[Stanleymonkey]

How about using heavy (possibly steel) balls to trip the 'pop-ups'? with the handle recirculating the balls so they fall down a 'pins on a board'arrangement which would generate a random path.

How in any way would that be random? Are you perhaps meaning “different”?[/quote][/quote]

I think that one would be applied to four or five different targets - the order in which they jump up to be shot at would be random.

 

[Stanleymonkey]

Generation of “pure” random is a very specialised thing (think cryptography level of special) so just what do you mean by random? Add enough gears you can create a range of ratios, but even an enigma machine can be predicted eventually and your losses for each transmission will be adding up for each one. Doing it mechanically might be less effective than having a few actuators and a simple computer driving them

Aidan

Fair point - just something mildly unpredictable might be a better description.