High torque motor and controller for rotating turntable

Hi there,

I’m a robotics newbie and am building a slowly rotating turntable like device. I’ve attached an image of the design. I’m looking to control the rotation of the ‘arm’ which is on bearings and exceptionally smooth - by using a motor controlled by a Raspberry Pi. I’m not too worried about the Pi control, but I don’t know how much torque I’ll need or how to calculate that.

I need to be able to control the speed from about 10 seconds per full rotation (6 RPM) down to about 60 seconds per full rotation (1 RPM). I’m not averse to using additional gears. I was thinking of using a bicycle gear assembly with a chain but am not married to that idea.

I was looking at this one pololu.com/product/1591/pictures (Metal Gearmotor 25Dx58L) which has an RPM of 12.

Does anybody know what type of motor I should get for my project? There are too many to choose from!

Thank you for your suggestions


Hello, Marc.

Without knowing the specific torque requirements of your application, I cannot say if that gearmotor is appropriate. You will need to figure out the torque requirements of your application to narrow down your choices. You might find
this blog post on force and torque helpful.

By the way, if you want precise speed control, you might want to select a motor that has an encoder or gives you the option to add one. An encoder will give you feedback that can be used to regulate the speed.

- Grant