Rotating object at 60RPM

Hi

I'm looking to rotate an object (probably going to be an LED lighting system) at 60RPM.

I'm familiar with using Arduino, but haven't had any experience with RC electronics.

Should I be using an ESC and somehow program it to maintain this speed on a normal servo motor? Also is this relatively low speed possible? I'd say as long as it is accurate to about 20 RPM and doesn't go lower than 60RPM it would be fine.

Thanks :)

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Replies to This Discussion

ah.... no.

Ah wow thanks Mike. :)

Also currently trying the mod to make the servo into a simple continous rotation motor, with any luck running it directly from 6V could do the trick.

If I have a continous rotation servo, and run it off a PWM controller, would it maintain the same speed even if the battery runs down a little? I'm thinking it wouldn't, as the PWM tells it 'how much of maximum speed and which direction' to run.

There are three lines into a servo, not two.
Use a regulated power source.

I don't believe I said there were two.

Ok will look at regulated power sources.

You can get relatively cheap optical encoders (about 30\$) that give your Arduino the rotational speed. Simply take the desired speed, subtract the current speed and multiply that by some suitable constant. Output that to PWM and it should work. (the most basic PID controller is this)

If you want it really cool you could probably use some diodes and a voltage regulator to create a burshless power transmitter, but the slip ring would be a lot easier I think.

Dear All,

I am using continuous rotation servo for 'Yaw' control of my camera gimbal. I am using it for stabilization around a setpoint/ target angle, using PID's.

If I give a target of say 60 degrees, the servo should adjust its speed in such a way as to make it to 60 degrees (in a circle of 360 degrees).

The AHRS system gives a DCM Yaw output from [-180 to 180], i.e. 0 to +180 degrees and sudden transition to -179 and goes to 0 in the reverse direction.

The problem I am facing is this transition around the boundary from +180 to -179. If my target angle is say 170 degrees, once it nears 170 degrees the servo speed reduces and when it reaches 170, the velocity becomes zero to a standstill. Having the same 'Target angle' if the orientation of board is such that yaw output is 180 and then a slight change in orientation cause a sudden change to -179 (This is a difference of almost 180 - (-179) ~= 360). The servo speed reverses from relatively slow to fast, due to this vast difference to compensate.

Is there a workaround? or a method to compensate for this problem? This is not there in the code. Any help is appreciated.

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