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Benefit of L293D
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Benefit of L293D

by jonvh on Wed Oct 09, 2019 1:44 pm

I'm new to Arduino, but not new to coding. I'm helping my son make a robot that he wants to build together, and I'm honestly really enjoying myself with it. I do have a question though. Nearly every tutorial sequence that I have found online and in the books that we've borrowed from the library, somewhere between lessons 3 and 5 there is a step by step tutorial on how to set up an Arduino to control a stepper motor. As we continue to plug along, I find many tutorials that insist on using an L293D chip to control the motor. But what I don't understand is why. What is the benefit of introducing a L293D IC to control the motor vs. controlling the motor directly with the Arduino?

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Re: Benefit of L293D

by adafruit_support_bill on Wed Oct 09, 2019 2:29 pm

The Arduino pins are not capable of sourcing enough current to drive a stepper motor. And they do not have any protection against the inductive reverse-voltage spikes that are produced when de-energizing the motor windings during stepping. So you need a circuit such as the L293D which is designed for the purpose.

As motor driver chips go, the L293D is a bit primitive by today's standards. It is a great low-cost way to learn the basics of motor control. But more modern chips like the DRV8833 have more advanced protections like current-limiting - which becomes more important when you start working with more powerful motors: https://www.adafruit.com/product/3297

https://learn.adafruit.com/all-about-st ... he-stepper

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Re: Benefit of L293D

by jonvh on Wed Oct 09, 2019 2:43 pm

That makes sense. It didn't occur to me that the Arduino may be capable of driving the motor, but that the motor controller provides protection. Thanks for clarifying. We're just goofing around with some pretty small motors for now. If we get into anything bigger I'll look into the motor controller that you recommended. Thanks again.

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Re: Benefit of L293D

by zener on Fri Oct 11, 2019 2:42 am

adafruit_support_bill wrote:The Arduino pins are not capable of sourcing enough current to drive a stepper motor.

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Please be positive and constructive with your questions and comments.