Stepper (or step) motors are really cool. They are perfect for automation or any time you need a motor to turn to a specific point, at a specific speed, in a specific direction. And, unlike typical motors, steppers are able to do all of this, and hold their position when they are not moving – The trade off is that they cant move as fast, and you have to power them at full power all the time, but you get total control in return.
teppers have a minimum amount they can move known as a step. You can feel these steps if you slowly turn your stepper by hand. The most common steppers have 200 steps per revolution, so all movement is in 1.8º increments (360º / 200). Controlling them can get tricky at first, so today we are doing an article on using the Big EasyDriver Stepper Motor Driver. The big easyDriver is the big brother of the easy driver we wrote about last year. It is able to take a lot more abuse and power, so it isn’t as easy to destroy as the easy driver, can power much larger motors, and it also gives you a little more control by letting you change the microstepping setting.
Motor Voltage / Current
A lot of people ask about what voltage they should use to power their motor. Well, when using a stepper driver, you are powering the driver, not the motor. The driver will take over powering the motor for you.
It is best to power the driver with the highest voltage you can ( up to 35V max for this driver ). This will allow the motor to spin faster than if powered at a lower voltage. Exactly why this is is pretty complex, but if you want to know more about it, you should really read this: Gecko Drive – Step Motor Basics
On the bigEasy driver is a mini potentiometer to control the current to the motor. This varies between 0ma and 2A (2000ma). You want to set it to whatever your motor is rated to. Too high, and you could burn the motor up, too low, you wont get all the power out of your motor. Note: The arrow indicators on the current adjustment potentiometer are backwards. Keep this in mind when adjusting the current limits. If you are running a higher power motor, you will probably want to put a heat sink on the driver as well.
Hooking it up
Even though there are some 30 pins on the Big Easy Driver, we only need a few to get this up and running. In fact, a good deal of the pins are actually just duplicates that are spaced out differently.
The barebones setup:
Power the driver with 8-35v – If using a wall adapter, make sure the adapter has at least enough current for the motor. A higher current/amperage rating is better, and just means it wont burn out. (The Big Easy Driver can supply up to 2 amps)
Connect the 3 control wires from the “gnd”, “dir”, and “step” of the Big Easy Driver to the Arduino as shown.
Connect the stepper motor to the driver – For me the red/green were one pair, and the blue/yellow was another. If this does not work for you, see the section below on finding your motors coil pairs.
For More Details: The Big Easy Stepper Motor Driver