Home Chapter 12 Maxuino/Arduino ULN2003 Stepper motor
Maxuino/Arduino ULN2003 Stepper motor

Another motor that is quite nice to use for accurate positioning is a stepper motor. Steppers have many discrete coils that allow them to step through the motor coils and you can use a counter subroutine to move the steppers in step.

This could allow you to count the number of steps to turn the motor one time for example. With a motor that steps 1.8% you would need to have 200 steps to go one full revolution.

Since the motors are accurate you can also tell them to go 50 steps for example and that would be 1/4 of a 360 degree turn. The challenge with steppers is they have not feedback and if you are holding the motor and it does not turn, while advancing the code telling it to turn, the motor or the program many not know it has not turned.

Notice the part number below is for a ULN2003 vs a ULN2803 and either part will work though pay attention to the extra pins on the ULN2803 and account for them in your design if that is what you are using.

Also note that the supply voltage is 12 volts and the GND rail is also tied to that power supply. It is important to tie that GND back to the GND rail of the Arduino you use to create the stepping code for this stepper motor.

You can purchase a stepper motors from Sparkfun or Pololu motors  

 
 

Code to drive the stepper motor using Maxuino.

 
 Copyright Ken Rinaldo

 

MAX MSP lessons continue in Chapter 13