Right current value for CD ROM steppers to calibrate with A4988 Pololu

Robotics and electronics discussion Mechanical design and actuators
1

Hi there, before all, Happy xtmas and happy new yeear for everyone!.

I’m newie in this topics and I got a many doubts about CD ROM steppers.I just wanted to build a CNC CD ROM 3 axis and I realized that these motors don’t have any description adn therefore I just can’t to know whos is the factory so that I can calibrate the right current value by means of A4988 Pololu that I got.

Could someome tell me how fix this problem?. Do I assume just one value and make the test-error ?

I`d appreciate very much your help guys!

Thanks a lot!

2

Hello.

If you know the original voltage the steppers operated at, you could measure the coil resistance to get an estimate of the current using Ohm’s law (I = V / R). You could measure the resistance of the coils with a multimeter, but you should be careful since low resistance measurements taken this way can be a bit inaccurate.

-Nathan

3

Thank you so much Nathanb that’s what I did for OHM law I calculate 5 volts/ 11 ohms (coils) and this result is 0.45 A (450 miliamperes) so I’ve calibrated my Vref A4988 pololu at 0.22 volts.I think it’s gonna be right.I didn’t build it yet.Today evening I 've calibrated my 3 A4988.I’ll se tomorrow if I have some time to get involve a little more.

A big hug to you and have a nice new year buddy!,

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did you make it work i’m at the stage where it only buzzes internally or stutters and i’m scared my entire project will go to shambles any help is appreciated

5

Hello.

This thread is 9 years old, so the original poster might not respond. However, if you create your own thread with details about your setup (e.g. power supply, stepper motor, microcontroller, connections), we would be happy to take a look. Pictures of your setup that show all of your connections as well as the simplest, but complete code that demonstrates the problem would probably be most helpful.

Brandon

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