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Topic: Project Using Three Servos and One Stepper Motor (Read 264 times) previous topic - next topic

bnomick

Hello all,

I am a student who is using an Arduino to program a project we are developing. I have a little experience with Arduino so I have some knowledge of the programming and circuitry. For our project we are using one NEMA 17 Stepper Motor and three separate servo motors. We will be using a bench power supply to power the motor and servos. My question is, is it possible to run all three servos  and the stepper motor with a L298N driver on the Arduino? I also found the Adafruit Motorshield v2.3 which supports two steppers and two servos, but is this necessary for what we are trying to do? I see you can stack these, but can I run the external power supply to the Adafruit Motorshield?

Thank you for any advice that you guys can give. I open for suggestions and appreciate any feedback.


slipstick

Normal servos do not need any shields or drivers, just power and one digital pin each, using the Servo library.

So it's only the stepper motor you need to worry about. An L298N driver might do it but I believe there are many better drivers available these days. That's a bit outside my area so I'll let someone else recommend one.

Steve

Robin2

Two or three hours spent thinking and reading documentation solves most programming problems.

bnomick

Hey Robin,

Thanks for the quick reply! We are powering a linear actuator as seen here:
https://openbuildspartstore.com/v-slot-nema-17-linear-actuator-bundle-belt-driven/


So the NEMA 17 Stepper Motor has the following specifications:

Shaft Size: 5mm
Torque: 76 oz*in
Step Angle: 1.8
Peak Current is 1.68A/phase
M3 Mounting Holes
4 Wire Bi-Polar
12-24VDC (Recommended)
RoHS Compliant

We have a bench power supply that we will be using to power the three servos and the single stepper. I was not able to find a datasheet that contained the rated current for the NEMA 17 Stepper Motor. I did a little more research and found the BigEasy Driver from Sparkfun which seems to allow a maximum of 2amps. Would this be sufficient to drive the motor?

Thanks again

- B

Robin2

At 1.68 amps I think the A4988 on the BigEasydriver will struggle, A Pololu DRV8825 would give you a bit more headroom. I suggest you look for a stepper driver that can provide 150% to 200% of the current required by the motor. Avoid running electronic equipment close to its limit.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

MarkT

Definitely DRV8825 or better is the choice to go for. 

The L298 is completely unsuitable for any low-impedance stepper motor like yours, which
require current drive, not voltage drive.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

bnomick

Awesome! Just ordered it, thank you all for your help!

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