Getting into small motors for kinetic art?

I have a wild idea, but no knowledge of the related world to get started. Someone give me a clue! So I have this idea for a layered piece of Glowforge art – that’s the easy part. I envision one of the pieces rotating… something simple perhaps a little rubber “drive wheel” at the bottom that makes one layer turn. Or maybe even connection at the center to a clock mechanism, turning at the speed of a second hand?

I have a vision of the effect but don’t know where to start with the how to make it do that. I’m smart, handy, and willing to explore/learn… if anyone out there has a good suggestion with where to start I’d love to hear it!

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A clock mechanism (which you can get in hobby stores or online for just a couple bucks) would likely be the easiest - presuming you can hook the layer to the mechanism. The issue you may run into there is weight - if your layer is (for example) an 8" piece of plywood, the mechanism likely won’t be strong enough - there are heavier duty ones available though!

There are also kits that let you program a motor so you can do something beyond just a simple swing (have it change direction, or speed, or whatever) but I’d figure out the mechanical portion before you get into programming :slight_smile:

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Most clock mechanisms have very little turning power, aka torque. As in they barely can turn the little second hand. The average clock mechanism isn’t going to be able to turn a layer of lasered material.

If you want to go the complicated but more precise route:

There are so many questions to ask here, it’s hard to know where to begin. Is plug-in on the table? How large is the item you’re turning, and how heavy? How quiet will this mechanism need to be? Will it always simply rotate, or do you want some control over its position? How small is “small”, as in how big or small does the motor need to be?

Once you have some of those answers they will put some constraints on what is possible for your project. After that, I’d start looking at places like mouser electronics to see what motors fit your bill. You should be able to get a rough idea of needed torque if you want to spec it really tightly, or you can just go overboard and spec out a much more powerful motor than you think you will need and be done with it.

If you want to just get something in place and try it, and sort of work around the motor:

Something like this might fit your bill.

https://www.amazon.com/Bringsmart-Electric-Barbecue-Synchronous-Reduction/dp/B07J54C84R

1 rpm is exactly the speed of a second hand, you’d just need to either center mount the motor on your layer or rig up a gearing system to spin your layer at the appropriate speed.

Unfortunately that motor isn’t specced out to the level of detail where they tell you the torque, but since it’s 18w and 110v, I suspect it has plenty. 18w is a lot of power.

You can probably find even better options for you, ones that are prewired/cheaper/etc.

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Just to echo the above from practical experience, you can forget about using a clock mechanism unless you buy a very expensive mains-powered commercial unit, such as those used in schools and such.

Even “heavy duty” consumer units can’t carry a laser-cut 1/32" acrylic hand, let alone any kind of more complex mechanism.

An option not mentioned is a continuous servo, as used in radio control. Generally they have 120º or so of rotation but you can buy ones that turn continuously, or modify a more common one. Lots of info, lots of sizes, tons of torque in larger models - and cheap.

Control can be a simple arduino, also cheap and tons of info on how to control servos is already out there.

Forgot to say - the beauty of servos (and arduino) is they can be powered from a standard USB battery bank - they’re designed for 5V. So you can wall-mount it or run cordless on a shelf/table.

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And generally really loud, too. Most servos I know are really mechanical-sounding.

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This is a great point. I don’t know of a cheap motor that could handle the torque required and be quite…

Not when run at very low speed as being discussed.

Of course if it was going to be wall-mounted, you might be able to create a weight-driven system like a pendulum clock.

We have some knowledge of that around here, right Bill? :rofl:

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That was my first thought. It wouldn’t be that hard if it didn’t need to be consistent movement (time).

But would still need to wind it constantly.

Well I wish I had a bit better mental picture of what you are doing but my thoughts go to stepper motor.
Giant rabbit hole but one every maker needs to fall down at some point.

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Two words: Stepper & Motor.

They’re cheap and plentiful in small sizes and can easily be driven with a stripped down Arduino or similar microcontroller with very little in the way of electrical or software skills required - just an ability to search the internet and follow directions. I’ve implemented a number of pretty advanced Arduino based projects over the years, and none of them required me to implement anything from scratch (though I am an engineer with the skills to do so).

There are also purpose-built stepper motor driver chips that are designed to continuously turn the motor at a fixed rate. I have a 3D scanner that came with a turntable that’s actually too fast for the scanner. I bought an off-the-shelf stepper driver chip to replace the driver inside the turntable so I could slow it down.

Steppers can be pretty noisy if run at high speed, but if you’re looking for clock-like step rates, they basically make as much noise as an actual clock does. But you have much finer control with a Stepper and of course, there’s no winding it up.

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Look into miniature steppers. You can find them on eBay in a variety of sizes. I have several that are less than 1/2 inch long including the worm screw. You can drive them with a cheap stepper driver or H-bridge, though I recommend the stepper driver if you want quiet.

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