Help with GBRL and Universal Gcode Sender with Arduino Hobby CNC Plotter
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??
Re: Help with GBRL and Universal Gcode Sender with Arduino Hobby CNC Plotter
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