Ardunio Project - Arduino Uno>STSPIN220> Nema 17 Stepper 2.7V 1.68A @ 1/256 Step

Hello all,

I am a complete rookie in the area of electronics but I would like to know if it's possible to control a Nema 17 Stepper 2.7V 1.68A with an Ardunio Uno connected to a STSPIN220. I thought I understood the basics, but the further I research, the more I realize I don't know. I'm all for trial and error, but I don't want to tear a rift in the fabric of space/time while I monkey about. In the end, helping me might just help save our universe (cheesy, sorry).

I've watched the DroneWorkshop YouTube channel's excellent video on steppers but I still am not clear on how to program/wire the STSPIN220 to run at a 1/256 microstep. I can see that I have to use the MODE1, MODE2, STEP/MODE3 and DIR/MODE4 to High/Low/Low/High respectively, but how do I wire that back to the Arduino and how do I code for it?

Finally, since the stepper seems to be rated at 2.7V, could I use a standard 5V powerbank to supply power, and if so, what should I be considering?

This Pololu page may be the of interest.

That driver will not supply the full current that your motor is rated for. Is there a particular reason that you chose that driver?

Hi Groundfungus (great name btw),

I was looking to connect a Arduino Uno (or most appropriate Arduino) to a Nema 17 Stepper Motor (linked). Given that I was trying to develop an equatorial mount for astrophotography, I wanted to throttle back the stepping to as low as I could go, preferably 256:1. Like I said, I watched the DroneWorkshop videos, but they didn''t address the specific requirements I was looking for.

Like I said, I am really a complete noob, but I can learn at a slow to middling rate. The A4988 stepper driver seems to have been designed for a higher voltage motor (12V), so I thought the STSPIN220 low voltage would be a better option for the 2.7V stepper. The specs said that the STSPIN220 was designed to "drop into" an A4988 setup, so I thought it would be fine..

? Oh, Happy New year BTW
STSPIN220>

Get a stepper motor driver board. They don't cost much. STSPINN220 only contains some transistors offering some current limiting. A driver board will have nice logic offering micro stepping, but not up 256. Usual is x2, x4, x8 and sometimes x16.
The stepper looses more and more torqe the higher the microstep value is.
A good driver board is something like the 6500, or 6600 serie.

Thanks folks,

So if I understand correctly, the NEMA17 stepper I'm looking at has a rated current/phase of 1.68A, and a voltage of 2.7V. This looks like its below the power capabilities of the A4988, but is better matched with the DRV8834 that operates from 2.5–10.8 V, and 1.5 A per phase continuously (up to 2 A peak).

The 6600 driver boards look interesting but aren't their operation voltages of 9 – 42 VDC too high for the 2.7V motor I was planning to use? What are the advantages of the larger driver boards like the 6600 versus something like the DRV8834?

Forget about the voltage for the stepper. Set the A4988 to the current You need. That's all. For currents close to maximum You glue a heat heat sink to the IC.
I use the A4988 at 12 volt, 1.5 Amp,heat sink and a little fan to keep them cold. That DRV8834 looks less interesting.
By the way. NEMA17 designates the mechanical interface, how to drill the holes in the mounting plate and tells nothing about the electrical properties.

Thanks for the quick reply Railroader.

Getting back to the A4988 makes me feel more comfortable. There's quite a few resources on the Uno and the A4988. It's 1/16 microstep resolution should be fine for my application. One thing though, I'm not sure the A4988 run off a USB 5v powerbank (the kind you use to recharge a phone) and portabilty is a key factor in the project.

Just out of curiosity, what issues did you see with the DRV8834?

The issue is the very low voltage limit of 10.5 volt.

Note that the A4988 needs a board that makes the multi stepping. It would consume many more I/O pins of the controller and code to make it run. Those boards are affordable. All You need to give it is direction and step. Enable if You need.

Sorry, I threw in another question in my previous post but you answered too fast (LOL).

One thing though, I'm not sure the A4988 run off a USB 5v powerbank (the kind you use to recharge a phone) and portabilty is a key factor in the project.

chardpp:
One thing though, I'm not sure the A4988 run off a USB 5v powerbank (the kind you use to recharge a phone) and portabilty is a key factor in the project.

Why not? Okey. Power banks need a certain minimum of current to stay alive. That varies from bank to bank and also depends on the consumption of current for the entire project. That can be tricked, if needed.

Did You read my remark to use a board carrying the A4988?

"Note that the A4988 needs a board that makes the multi stepping. It would consume many more I/O pins of the controller and code to make it run. Those boards are affordable. All You need to give it is direction and step. Enable if You need."

I did see that. I thought that connecting the MS1, MS2 and MS3 pins of the stepper driver to the Arduino Uno and applying the appropriate coding was the method for setting up microstepping.

the STSPIN220 looks to be the perfect solution for your needs.
can take in 10 volts. way more than you need
can handle 1.3 amps, also way more than you need.

check the notes on the pololu site

the pololu site says " The module has a pinout and interface that are very similar to that of our popular A4988 carriers, so it can be used as a drop-in replacement for those boards in many applications. "

all this is moot as you have not listed the application

one of the unwritten forum rules is " no application = total speculation "

A worm gear with a stepper is the most common for a telescope and a NEMA 17 is massively overkill for scopes under 12 inches.

============

"I'm all for trial and error, but I don't want to tear a rift in the fabric of space/time while I monkey about. In the end, helping me might just help save our universe (cheesy, sorry)."

sorry, I am not buying this... you ARE trying to look into the space/time and monkey about.
THAT is what astronomers do !

as for the saving of the universe, sorry on that too. an observer is not a player and humans are not players on a universe scale playing field.

a bit about steppers

you can run a stepper on it's nameplate voltage and current without any problem.

When you want to get higher Performance, you MAY, if you REALLY NEED TO, you MAY increase the voltage.

since you want to run the motor slow, you have no need to increase voltage or performance. a properly mounted scope will be in balance and only a tiny amount of power is needed.

A NEMA 17 could easily run the 60 inch scope at Griffith Observatory.

Hi Dave-in-nj,

As far as the application goes, I am trying to build a portable star tracker for a balanced dslr/lens/small telescope combination that I can power with something like a standard 5v powerbank. My tracker design doesn't use the standard gears you mentioned but the NEMA 17 I had in mind does have a 100:1 high precision planetary gearbox that I want to take advantage of. I also don't mind the size/power of the motor because I should be able to reuse it in future projects (like a proper 2 axis goto mount for heavier optics) once I understand the electronics better.

Now I'm back to being a little confused. Earlier posts had me questioning the STSPIN220.

chardpp:
One thing though, I'm not sure the A4988 run off a USB 5v powerbank (the kind you use to recharge a phone) and portabilty is a key factor in the project.

Things like that are in the "A4988 datasheet" (Google that).

Minimum motor supply is AFAIK 8volt for that chip, so not possible to use a 5volt powerbank.

High motor speed is only possible with a high supply voltage.

Stepper motors are a poor choice for battery power, because they draw full current when standing still.
Leo..

If you want to run at 5V the A4988 or DRV8825 drivers will not work. They need a minimum of 8V. Now that I know more about the application I will agree with dave-in-nj that the STSPIN220 driver is a good fit.

chardpp:
Hi Dave-in-nj,

As far as the application goes, I am trying to build a portable star tracker for a balanced dslr/lens/small telescope combination that I can power with something like a standard 5v powerbank. My tracker design doesn't use the standard gears you mentioned but the NEMA 17 I had in mind does have a 100:1 high precision planetary gearbox that I want to take advantage of. I also don't mind the size/power of the motor because I should be able to reuse it in future projects (like a proper 2 axis goto mount for heavier optics) once I understand the electronics better.

if you are talking a 'barn door' or something similar that will run for less than an hour, then your application is possible.
steppers are power hogs, the size of your power bank needs to be able to handle the load for the time.
lots of guys use car batteries for star gazing.
100:1 gear ratio and you have a LOT of power.
the weight of the optics is not important. the original panama canal gates were so well balanced.that a single 25 hp motor can move the 662 ton gate.
if you are using a planetary gear box (fitting name for a telescope) your power needs are not that great.
work out the mechanics,
mount the motor and try it with a multi-cell power supply.
watch how long that works.
reduce voltage to where it no longer works, then bump it up about 30% higher.
time a run, then figure how many batteries you need per hour of use.

every volt over the voltage needed to drive the motor is wasted.
this is a case where you want to keep the voltage as low as possible and still be able to drive the device.

Please post a link to something similar to your project.

** do you know a good CCD camera for use with a simple telescope ?
I have a 3 inch and a 4 inch and use them once or twice a year to look at the moon, totally manual. but I have a full manual drive that is screaming for motors.......

I plunked the specs of the NEMA17 I wanted to use (2.7V/1.68A) into this *power calculator *and got a charge lifespan of 11 hours using a large powerbank (10,000mAh at 5V). Based on what you're saying, I've missed something in the analysis. I really don't want to carry a car battery in my backpack while hiking. That would suck.

I'm sure I'll have other questions, but until then, enjoy your new year!!!

Thanks guys for your help working through this.

dave-in-nj:
reduce voltage to where it no longer works, then bump it up about 30% higher.
time a run, then figure how many batteries you need per hour of use.

every volt over the voltage needed to drive the motor is wasted.

Are we talking brushed DC motor now?
Because that does AFAIK not apply to stepper motor chopper drivers.
They feed a constant power to the motor, set by the current pot.
A higher supply voltage means a lower current draw from the supply (same power).
Leo..

Wawa:
Are we talking brushed DC motor now?
Because that does AFAIK not apply to stepper motor chopper drivers.
They feed a constant power to the motor, set by the current pot.
A higher supply voltage means a lower current draw from the supply (same power).
Leo…

Since this is a battery powered application, reducing the current to the motor does reduce power and the goal is to tune the motor to the lowest current and voltage that will deliver reliable and sufficient power for the application. Also to acheive the lowest possible heating.