Arduino and stepper motor

[Pierre-o]

Hi everybody,

I would like to use 3 stepper motor with an Arduino board, and I'm not really sure of the board I should use Uno, Mega, Duelanove... it's to move a kind of 3 axis CNC machine I'm building. And I would like to be able to give some commands to the motor via potentiometer and different input sensor (one per motor).

Any suggestions?

[Monty]

For what it's worth, Arduino provide a forum http://arduino.cc/forum/ that specifically caters for this kind of question, so you'll probably find better knowledge there.

[Toby Catlin]

Any stepper motor suitable for CNC work cannot be driven directly from an Arduino and so you need some extra hardware to be able to supply enough current to the motor coils. I understand this can be achieved with a couple of H-bridge chips but most people use a more complete solution like the A4988 stepper motor driver:

http://www.pololu.com/catalog/product/1182

You connect the Arduino to the step and direction pin of the board. For each pulse you send on the step pin will cause the motor to move one step. The Arduino code must keep count of the direction and steps to keep track of the xyz position.

The CNC machine I recently build i used a RAMPS 1.4

http://reprap.org/wiki/RAMPS_1.4

This board is designed for RepRap 3d printer and holds 5 stepper motor drivers and will attach to an Arduino Mega. It has features such as endstop inputs and mosfets for driving extruders. You can also use the open source code Marlin & PrintRun to control the motors and run gcode. You can get a RAMPS board already fitted with drivers and ready to go from ebay for around £70

Another option is the L6470 driver:

https://tindie.com/shops/ElectricLaboratory/chainable-intelligent-stepper-driver-l6470/

These drivers do a lot of the processing for you. You tell it what coordinates you want the motor to move to and it calculates the rest, including acceleration and deceleration.

hope this helps

Toby

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[Pierre-o]

Thank's for the information, I already have an Arduino Uno and a motor shield from another project but the problem is I can only use two stepper motor in it and when the motor shield is plugged I can't really connect anything else

 

Does any one already tried that?

https://www.sparkfun.com/products/10735

[Toby Catlin]

That board is based on the A4983 driver which is basically the same as the A4988 but has overcurrent protection.

You could buy three of these and they would drive Nema 17 motors without trouble. It is not uncommon to overheat and blow these driver chips so bear that in mind for your design. The RAMPS board means you can change out the chips when/if they blow. You will want some heatsinks and probably a fan to keep the chips cool.

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