Looking for advice on how to set up a motor to rotate at a specific speed


I am building a music box, and would like to install a motor of some sort to rotate the mechanism. Obviously this would need to be rotating at a fixed speed.

I'm just wondering whether stepper or servo motors would be most ideal, and what I would need in terms of a driver to make it work?

What precision in the rotation do You need?
What range of RPM are You talking about?
My suggestion is to use a simple DC motor, eventually geared.
The driver handling the motor will be very simple and cheap.

How will you know the motor is turning at the required speed? You have to measure it.

Somewhere in the range of 30 - 60 bpm


Search for a geared DC motor having a max of 100 RPM.
Here is a possible motor: Dc 12v 300rpm geared motor high torque 37gb-550 gear reducer motor Sale - Banggood.com-arrival notice-arrival notice

Yes rpm, sorry. I was thinking bpm because I plan to figure out what voltage is required by comparing the output of the mechanism with my motor hooked up to a metronome that is going at the correct bpm. (maybe there's an easier way, but I'm thinking I could just tinker with a metronome for 5-10 minutes and get the desired result?)

Thanks for the link! I will get to work.

Aha, beats per minute.
Running only in one direction? That makes the driver cheap.
I assume the load on the motor is constant. Then using PWM and some testing hopefully a satisfying constant can be found.
What is this project actually supposed to do?

I wrote some code where I can specify notes and note lengths, and it then generates a 3d model of a music box mechanism (or at least the part that plucks the notes) that would make the song I inputted if it is hooked up to a working comb (the thing that makes the music when plucked). So my plan is to 3d print this model and hook it up to a motor to make a music box.

Yes running in only one direction.

Having only a little knowledge about music terminology I don't get it.
Notes I know, hole, half, quarter etc, CDEFGAH.... but I don't se the connection with the running of the motor. Please, try again..

So the model is a cylinder with spikes sticking out of it corresponding to the notes that are in the song. If I programmed the same note into the model 4 times, say 4 half notes one after the other, there would be 4 spikes in a line on the cylinder. When the cylinder rotates, the spikes will move. If I place a set of teeth that, when one is plucked, a note is played, so that it is up against the cylinder, then when these spikes move into a tooth, they will pluck it.

I am planning on hooking the motor up to the cylinder, so that the cylinder gets rotated.

The rpm of the motor needs to be regulated, because the speed of rotation of the cylinder will determine the speed at which the song I've programmed onto it is played.

Maybe I got it now.

Have a look at this link: wintergatan marble machine - Bing video

My guess is that it's important that the speed is kept at quite a constant RPM, with the option to change speed, with quite some precision? If You're a musician that is likely important.

Since you would want an accurate speed control.
Add an encoder.
Lots of tutorials.
Typically used for speed control.

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