Help with GBRL and Universal Gcode Sender with Arduino Hobby CNC Plotter

[JonnyAlpha]

Hi;

I have built a DIY CNC plotter which I have been having problems with and started a thread here.
I have now managed to get both the X and Y axis working using a some stepper test code which just runs the motors clockwise and anti clockwise.

I am now working on the next step which is to send a Gcode image for printing and here in lies the next problem.

I am a little confused with how this is supposed to work. I understand that the Arduino needs to have code running on it to receive movement commands based on the image to be printed and I need software on my Mac to interpret and send the image data over the USB port to the Arduino.

Looking at various guides I think I need GBRL on the Arduino and Universal Gcode Sender on my Mac. After a lot of head scratching I have managed to get UGS working on my Mac but I now think my problems lay with the software on the Arduino.

I have followed several guides but none seem to be up to date with the latest Sketch (1.8.2) and I am not sure I have the Arduino software configured correctly. It seems that the code for GBRL is all embedded and not visible but how does it know what pins I am using??

Any help would be great

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[Biggs427]

1.8.2 is the latest version of the Arduino IDE.

You will need the last version of GRBL. Which is 1.1.

Intructions are on the GRBL wiki:
- Compiling: https://github.com/gnea/grbl/wiki/Compiling-Grbl
- Flashing: https://github.com/gnea/grbl/wiki/Fl...-to-an-Arduino

I'd try the flashing instructions first. It seems that now they have pre-compiled .hex files and you only need HexLoader to flash your Arduino.

Once You flashed your Arduino you should see it in your UGS given that you have selected the right COM port.
USG.jpg

The pinout can be found here: https://github.com/gnea/grbl/wiki/Connecting-Grbl

[george4657]

To drive a stepper you need a H-bridge circuit which is what your L293D are. The h-bridge requires 4 inputs that control how the power flows in the circuit.
GRBL outputs only 2 controls, step and direction. To use this you need a stepper driver that takes step and direction and does the conversion to drive the H-bridge.
I assume your test circuit outputs 4 lines to each motor so it does the timing that a stepper driver such as A4988 does. You could drive a system using the 4 outputs but I do not know of a software that reads gcode and outputs these steps.
You say the original project went to a driver board,it was for these reasons. I don't know what he was using to drive the original.
You could add a L297 to do the conversion from step to direction but it would be easier and cheaper to just buy 2 A4988 driver boards to replace the L293D. You would need to develop or find the proper circuit. See https://www.pololu.com/product/1182

George

[chucketn]

Johnny, I am using Arduino Uno, CNC shield v3, grbl 1.1, and grbl controller v 3.6.1.
My plotter setup is 3 axis CD-rom steppers. I want to use a full stepper axis to lift and drop pen instead of a servo.
grbl controller is used to connect to grbl on the Arduino.
I have the mechanics finished to the point of 3 axis movement, but have not added the pen yet.

Chuck

[vidio1]

Here's a link to a YouTube vid using freeware to convert an image to a Gcode file.