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Pololu A4988 and CDROM stepper


#1

Hi,

I’m trying to drive a CDROM stepper motor (4 wires, ~10 ohm / coil) with Arduino through A4988.
On delay less than 1 milisecond the motor is working, but i think it miss some steps.
When delay is more than ~ 1.5 milisecond the motor is not running (i can hear only some buzzing) and on increasing the voltage from trimmer the buzzing became high pitch squeal.
I changed the wires from A4988 to the motor, change A4988 power supply (from 12V/1A to 9V battery), powered Arduino from USB or from separate power supply but i get the same results.

What else should i try ?

Thx,


#2

Hello.

Could you tell me more about your setup? What are the voltage and current ratings of your stepper motor? What did you set the current limit on the A4988 to? Could you post a picture that shows how you have everything connected?

By the way, a 9V battery is not a good power source for motors since it cannot not supply much current. You should use a power source that can supply an appropriate amount of current to your system.

- Grant


#3

if you are using stepper motors and the drive rails out of a cd/dvd drive they need to be powered with 5 volts. they seem to be fairly robust as long as you dont mess with the stepper/screw mounts. I use a old computer power supply. mine are set with ms1, ms2, ms3 set to high. i have turned the adjustment screw down. mine rotate 360 deg. but have a flat spot on the adjuster i have set mine to the same position. the motors wine a little when overpowered i turn the adjustment screw unitll they dont wine. they produce more heat than normal due to the 8 volt. working on either using a heat sink on the motor or putting resistors in the output wires.

as the wires come off the stepper motors. they are {coil a, a1} {coil b , b1} you will need to invert two of the wires to make that stepper motor work correctly. I dont know if inverting a and b is the correct choice but one must be inverted to make it work. i usually invert b.

if you get them wired wrong you will never adjust them. use a volt ohm meter and fint the two wires that ohm. the other two are the other coil. the outside two wires are what i usually call coil a.