Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: George221 on January 30, 2013, 05:25:53 PM

Title: I NEED HELP WITH STEPPER MOTOR~
Post by: George221 on January 30, 2013, 05:25:53 PM
i got few stepper motor from robotshop :   12V 0.68A 125oz-in Unipolar Stepper Motor

(http://www.robotshop.com/ca/rbsoy14-soyo-unipolar-stepper-motor.html (http://www.robotshop.com/ca/rbsoy14-soyo-unipolar-stepper-motor.html))

Question: i wanna control it that it can move both direction, so i tried to use darlington array uln2004A
                but the collector-current rating is 500 mA. will this burn when driving 0.68A stepper.

                is there another darlington array with higher current rating ? or other way to drive this stepper in both directions.
               
Title: Re: I NEED HELP WITH STEPPER MOTOR~
Post by: waltr on January 30, 2013, 09:41:54 PM
You can use discrete MOSFET, Bipolar or Darlington transistor instead of an array. An arry is not needed for bi-directional control of a uni-polar stepper motor.

Try googling 'uni-polar stepper drive' for lots of circuit examples.
Title: Re: I NEED HELP WITH STEPPER MOTOR~
Post by: jwatte on January 30, 2013, 09:44:41 PM
Pretty much all motor drivers these days use MOSFET transistors.

Because your motor is unipolar, you need four transistors. Four N-channel MOSFETs will work just fine, and you can buy power MOSFETs with logic-level I/O for about $1 each from places like Digi-Key. Adafruit also sells them.

You could also get a dedicated unipolar motor driver circuit, but I don't think you'd get anything out of that that you wont' get out of just discrete MOSFETs.