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Author Topic: more stepper motors & current question  (Read 335 times)
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Hi all.
I am completely new to all this so I apologise for the newbie questions, though I have tried looking for an answer before posting.

I have an Arduino mega and for my new project I have two questions:

First question is how I could control 3 strepping motors. I understand I would have to get the Arduino Motor Shield(that is because of the increased load demands of the motor I guess?) but that can only drive 1 stepper motor. Is there another way? Can I stack more Motor Shields(probably not)?

The second question has to do with servos. I realise I have to use external power as they tend to draw significant current. Is it possible to damage the arduino board? I mean, I suppose servos like this one could draw -depending on the load- as much as 500ma or even more. Could the board handle that?

That's it for now and thank you in advance.
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You can drive any number of motors from an arduino but the stepping library can only drive one at any one time. This means if you want two or more motors turning at once you will have to write your own code to do it.

Yes you are best if you have a separate power supply for servos.
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Welcome keraynopoylos,
I have 3 drives hooked onto my Mega .. they take 6 pins each, that's all. You supply each driver with external power. I've got a stepper-class and a 2d pen-class (synchronizing 2 steppers) that you can get to work with. Both classes has a lot of redundant code and needs a clean up, but that's just how it is.
Pop me a mail at carsten@troelsgaard.net if I don't get back (it's a big park to get lost in here)
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Or you can use Stepper Drivers - they usually use 2 (some times also an enable input or ready output) Step & Direction. That approach would mean that each stepper would need 2 wires. You might look at the GRBL shield, was built to work with the GRBL CNC code, but would work with your code also.

or take a look at this unfinished approach - http://arduino.cc/forum/index.php/topic,84809.0.html - in which I have done some work to use an Arduino, and finally an ATtiny2313 as a stepper controller. Take a Step and a Direction input, controls 1 stepper. Biggest part of the cost is MOSFETs sized for the steppers you want to use. I have been playing with some 9.5A MOSFETs that cost about $2.56US. Needs 4 for Unipolar motors. For Bipolar motors you would need to use H-Bridges or pay for a lot of therapy...
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