Swap EasyStepper for a A4988

Using Arduino Project Guidance
#1

Hi

For my first project I will (try to) use 2 stepper motors (NEMA17) for a cam slider. For that I bought 2 EasyDrivers, and because I didn't know what to look for in the specs when I ordered them, I'm now stuck with 2 750mA drivers while most nema17 require 1+A... that's not going to work. I've read (on this forum) that A4988 will go up to 2A so they should be good to go. I've found a driver that (probably) should do well, on Ebay.

Will this work OK? My sketch needs the steppers to be in 1/4 mode and this one does that too but I wonder if there are any connecting differences compared to the easy driver? I'm using AccelStepper.

I will use the easy driver to control the shutter using an optocoupler, now that I have to lying around :slight_smile:

Thanks a lot for reading.

#2

NEMA 17 just defines the dimensions of the mounting plate of the motor. It has nothing to do with motor current or other characteristics.

You need to find the actual winding specifications (winding resistance and maximum current) for your motors.

#3

Post a link to the datasheet for your stepper motor.

The Pololu DRV8825 has a little more amps capacity than the A4988.

AFAIK the Easydriver defaults to microstepping whereas the A4988 and DRV8825 default to full steps.

The Pololu web pages for these products have very good wiring diagrams.

...R
Stepper Motor Basics
Simple Stepper Code

#4

AFAIK the Easydriver defaults to microstepping whereas the A4988 and DRV8825 default to full steps.

#5

Thanks for the answers, I thought the 17 was a range of motors as most that I saw had about the same specs. My mistake, its, 1.7inches in size :slight_smile: Learn every day.

The motor I'm looking at now (since the ones I've previously ordered went out of stock somehow) are these: Link to steppermotor.

Thanks for helping!

#6

Robin2:
AFAIK the Easydriver defaults to microstepping whereas the A4988 and DRV8825 default to full steps.

Leo102:
AFAIK the Easydriver defaults to microstepping whereas the A4988 and DRV8825 default to full steps.

Why copy and paste what someone else just said?

#7

Thanks

I've found the ones that Robin2 mentioned here: Another link on ebay.

So these should be good for what I need? I only have one motor that's needs some power (to move the dolley, maybe even on a bit of a slope) and one lighter/smaller stepper for the rotation. I will use the new drivers for both.

One thing is not exactly clear and maybe you can help me with this (again). On the EasyDriver I can set the microsteps by setting Ms1 and MS2 to LOW/HIGH (standard HIGH). Does this work the same? I don't have any pins free anymore to control this as a lot of pins are buttons for leverswitches and the LCD menu, I need them to be in 1/4 step.

Thanks

#8

The DRV8825 should be fine with a 1.5 amp motor. Just make sure you set the current limit correctly.

You can "hardwire" the microsteps setting.

I suggest you try the motor with a simple test program on full steps before you try anything fancy.

At that price I would but a few driver boards in case of poor quality control.

...R

#9

Thanks Robin, will order a few. I realize that the build quality might be better from pololu but shipping costs to the Netherlands are pretty steep. The Chinese sellers on eBay ship for free or a for a low fee, which keeps thing manageable.

Thanks!

#10