I have a stepper motor controller with software that puts out a maximum of 1A per step.
I want to use a larger stepper motor with this controller, a nema 17 bipolar motor that requires 1.68 A per step.

Is there a little board that I can add on between the controller and the new stepper motor to amplify the amp output to drive this motor?

I'm not sure it will require the full 1.68 A as it is under very little load, but I don't want to burn up the controller.
The motor will not be under constant use, more like a few steps at a time for position correction.
Help?

Thanks
Greg

 

Welcome to AAC.

Which controller are you using?

 

It's a controller made for telescopes by Lunatico Astronomical in Spain. It's called a Platypus 2.
It controls 3 steppers (1 A each) and I only need to increase the output of one of them.

 

It's a controller made for telescopes by Lunatico Astronomical in Spain. It's called a Platypus 2.
It controls 3 steppers (1 A each) and I only need to increase the output of one of them.

You should be able to use an L298N based module, like these. They can handle 2A.

 

That would be great.
I might need a little wiring help given that these little boards from Amazon hardly ever come with instructions.

There are only 4 pins coming out of the Platypus for each stepper so it would be 4 pins in to the L298N and 4 pins out to the stepper, plus power inputs.
The Platypus runs on 12vdc so it would be handy to be able to power the L298N with the 12v?

 

That would be great.
I might need a little wiring help given that these little boards from Amazon hardly ever come with instructions.

There are only 4 pins coming out of the Platypus for each stepper so it would be 4 pins in to the L298N and 4 pins out to the stepper, plus power inputs.
The Platypus runs on 12vdc so it would be handy to be able to power the L298N with the 12v?

The L298N uses 5V logic, and can handle up to, I think, 36V for motor power. You might need to use a level shifter of some kind to drive it from the outputs of the current controller/driver. Since this is battery powered it would be good to avoid simple resistors which would work but might waste power.

 

"level shifter"?

 

"level shifter"?

12V to 5V. Strictly speaking a level shifter is usually something that does 3V3 <—> 5V conversions for compatibility, but it’s the same idea. The onboard driver is going to be expecting to drive a motor at 12V, not a logic input at 5V.

 

Thank you!
I found an article about this board and the arduino that suggests that there is an on board converter for the 5v logic circuit as long as the jumper is in place?

 

Thank you!
I found an article about this board and the arduino that suggests that there is an on board converter for the 5v logic circuit as long as the jumper is in place?

There is an onboard regulator so you can power the board with 12V, but the logic inputs are always 5V.
I think, though I might be giving you bad advice because the Platypus is directly driving the motors for microstepping, and the L298N is “too smart”.

Let me find you a simple MOSFET driver instead.

 

I‘ve got some boards that are appropriate but I have to track them down because I don’t immediately find them from the usual sources and so I am not sure where I bought them. Give me a bit and I will do that.

 

Thank you!

 

OK, here you go. These should do the job though you will need 4 per motor. Each will handle one wire. They also have the advantage of being able to take the 12V in as the logic signal so you can just wire them to the existing outputs.

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The common and one of the motor wires goes to the solder terminals at the front. Power for the motor goes into one set of screw terminals on the back and the output tp the motor to the other set. They are labeled. When the controller sends a pulse to the stepper coil, it will turn on the MOSFETs, and supply current from the screw terminals.

 

You may be able to find these on Amazon, but my preliminary search failed. The board is labelled “XY-MOS” on the back.

 

Oops, found them!

 

Wow!
Such a deal.
So I would put each wire from the Platypus output to the PWM+ and gnd, and the output from the Out + and Out - to the stepper motor and the DC+ and DC - from the 12v DC power supply.
Sounds like something even I can figure out.
Many thanks for your brain time!

 

Wow!
Such a deal.
So I would put each wire from the Platypus output to the PWM+ and gnd, and the output from the Out + and Out - to the stepper motor and the DC+ and DC - from the 12v DC power supply.
Sounds like something even I can figure out.
Many thanks for your brain time!

It should work as expected. If you run into any trouble don’t hesitate to ask more questions.

 

Thank you.

 

One more question.

The PWM and GND input would be from A and A' phase.
And the B and B' phase.
So I would need two of these boards to power a Bipolar stepper motor.

Did I get that right?

 

Or
A and V+
A' and V+
B and V+
B' and V+

So 4 boards ?