Stepper motor not responding to Arduino Gcodes


I've been trying o achieve the goal of turning the stepper acc. to Gcodes i enter. But, my stepper motor shows no response to any of the Gcodes i enter in serial monitor.
I'm using GRBL1.1 and latest arduino.

It't very important so please help

Any suggestions please

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More details needed

Hardware ?
Circuit ?
Code ?


Arduino Uno
L298 driver
Stepper motor
Grbl v1.1
Universal Gcode sender V2.0.7
Java RE latest

I think the bit you are missing is the Arduino UNO sketch that accepts the Gcodes, parses them and drives the stepper.
Warning none of the links below parse Gcode :frowning: but should give you some ideas

Multi-tasking in Arduino has a complete stepper example
driven by user (serial) input and a sensor.
Arduino Serial – Reading/Parsing covers the basic of reading from Serial (using Arduino Strings or my SafeString library)
The Serial Basics - Updated covers somewhat similar ground but using low level char[ ]'s directly and string (lower case s) functions.
Of course I use my SafeString library :slight_smile:

Arduino Serial I/O for the Real World covers in detail handling large inputs.

I am not aware of any version of grbl that supports L298 drivers. Grbl uses step/dir drivers like A4988 or DRV8825. What version of grbl do you have that is modified to use the L298?

I simply have grbl 1.1. So what driver should I use?

What exact stepper motors do you have? Post a data sheet.

If the steppers are bipolar and the coil current is less than 1A, the A4988 is good. Up to 1.5A the DRV8825, 0.5A to 4A the TB6600 drivers are popular. Those are all step/dir type drivers.

All of those driver will need the coil current to be set before they are used. See instructions on the linked pages.

So, acc. to what you are saying. Do i need a stepper driver and CNC shield both for this operation?

The answer to that depends on what exact stepper motors you have.

You will find that this help thing will go faster if you answer questions.

The proper stepper drivers, for modern bipolar steppers, are always better than the ancient, inefficient and just inappropriate L298 or L293.

and My motor is a unipolar motor

Unipolar steppers usually do not take an H-bridge to run. Can you post a schematic of your wiring?

I found this. It is supposed to work with 4 wire H-bridge drivers. I have no idea if it will work for you.

My thought is that if you want to work with grbl, use steppers and drivers that grbl was written for. And, with an Uno, the CNC shield makes a lot of sense. It is set up to use grbl with very little work. The CNC shield has accommodations for limit switches and other control signals as well as stepper drivers.

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No dice I'm afraid, you'd need 4 pins per stepper for unipolar use and there aren't enough pins!

Bipolar motors driven by a step+direction stepper driver are required for GRBL.

Also you don't get microstepping drivers for unipolars which is probably a show-stopper anyway, microstepping is vital for vibration and resonance control.

How many wires is the motor? 6 and 8-wire motors can be used both unipolar and bipolar, 5-wire can't.

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