Hi, so I'm new and I just wanted to ask about building some kind of rotating device. I'm a totally electronically illiterate, so please forgive me.

I'm working on a video project and for one shot I want to have the camera in the centre of a circle of people, with the camera rotating in place. I had tried using a turntable (record player) but it spun too quickly and the filmed images were blurred. I tried a number of ways of slowing down the rotation eg: putting weights on the turntable, wedging cards under the turntable, slowing it with my finger but it was hard to get a constant speed. Manually turning the turntable has the same problems!

Is there a device, like an electric motor I could use that allows me to set/control the speed of rotation? I've racked my brain/s and can't come up with anything and the shot is absolutely critical to the project! Aahhh! Anyone know anything that could be useful?

 

Get a disco ball and hang the camera from the string isnted of the ball?

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Hmmm...maybe though I'm not certain suspending the camera is going to be stable, I need a very solid locked in rotation, no wavering up and down, just around on the central axis.

Is there not something like a stepper motor? I'd be greatful if someone could give me even some keywords to search out for...I literally don't know anything about this type of equipment!

 

Well you just have to steady the camera, it wont swing up and down from the rotation just if the base moves.

Anyway yes a stepper motor would be a good solution.But note that stepper motors need electronics to get going.What it basicly dose is pulse 4 windings in the right order the faster you do that the faster it spins,since each of these pulses thurns the motor a exsact number or degrees(how many depends on the motor) The down side is that they are normaly pretty noisy

A nother solution is a DC motor with a rpm counter so its regulated to a constant adjustable speed.The quick way of regulating it is to simply put a nother DC motor on the same shaft and meshure its output voltage.

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Check the surplus supply and robotics places, they often have DC motors that are geared down. Look for gearhead and gearmotors. Do you have a given RPM in mind?

To some degree you can change speed by changing the voltage. For example if you found a 12V 5RPM motor running it at 6 volts may give you a speed or 2RPM. Do not expect it to be linear.

I am thinking a stepper motor would be too jerky.

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L297 + L298N combo can do half stepping and with a decent stepper motor (10+ steps per full rotation) it should turn smooth .. anyhow, without stepper or servo I do not see how you can achieve controllable and steady RPM. If speed does not need to be precise, then any geared motor will do.

 

I do not know much about steppers.

Once a DC gearmotor is up to speed, it should provide uniform speed if the load is balanced.

The OP describes himself as "electronically illiterate". Changing speed by adding or removing a few cells is something he could do. Setting up a stepper motor may be too advanced.

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