Hey guys I wanted to get a step motor running from a PIC that we used from our labs at school. Ive done some research on step motors and somewhat figured out how it works, however Im lost as to how exactly the interfacing works between the motor and the PIC. Ok so I know that the step motor has three modes, wave stepping, full stepping or half stepping. Now im planning on moving 45 degrees performing some action and then moving another 45 degrees. Assuming Im using http://search.digikey.com/scripts/DkSearch/dksus.dll?pname?site=us;lang=en;name=403-1018-ND which has a step angle of 15 degrees I would want to have 3 steps issued to my step motor.

My question is am i connecting the microcontroller pins directly to the step motor or to a driver that is then connected to the step motor? I just cant wrap my head around that...like how do the step sequences work for this step motor?

Thanks alot guys

 

Connect to a driver chip, the driver to the motor. For a unipolar motor the simplest dirver is a bunch of darlington transistors as 4 low side switches. unl2803 ( from memory, probably wrong ) is a chip with 8 transitors ( 2 motors ) and .5 amp current.

 

How do you determine the step sequence for a certain stepper motor? is this provided with the datasheet for the motor? Im not exactly sure how you would be able to determine which sequence to turn the coils on for an arbitrary stepper motor

 

Data sheet is usually a help. This works for unipolar motors http://www.opencircuits.com/Stepper_Motor_Tester

 

Data sheet is usually a help. This works for unipolar motors http://www.opencircuits.com/Stepper_Motor_Tester

Awesome resource but I need to find a stepper motor that im gonna be using before I get to use most of that infromation! I want to have a stepper motor that uses these stepping sequences but im not sure what it would be...as in how many phases/coils it would be...all i know is it would be unipolar with i THINK 2 phases or 4 coils. If anyone could help point me in the right direction that would be great.

normal sequence.
Step Q4 Q3 Q2 Q1

1 0 1 0 1

2 1 0 0 1

3 1 0 1 0

4 0 1 1 0

wave drive sequence.
Step Q4 Q3 Q2 Q1

1 0 0 0 1

2 1 0 0 0

3 0 0 1 0

4 0 1 0 0

The half-step sequence.
Step Q4 Q3 Q2 Q1

1 0 1 0 1

2 0 0 0 1

3 1 0 0 1

4 1 0 0 0

5 1 0 1 0

6 0 0 1 0

7 0 1 1 0

8 0 1 0 0