Grant H
not a llama
and all other cnc and arduino speaking persons I?m having life issues and need some help.

I have a long term goal of building a portable 24? cut area cnc plasma cutter that can be stored on a wall when not needed.

Figured the best way to start is to build a plotter/drawing machine.
I am vaguely familiar with arduino able to grab code snippets from GitHub and piece them together to make things happen like WiFi fermentation and gardening controllers cascading led under glow lights for my tool box etc. simple stuff.

I stripped an old 3d printer for components and Built a plotter with a servo controlled z axis pen for lift and drop
I have x and y figured out steps calibrated limit switch?s etc. the home cycle works soft limits are good.

I had a hell of a time getting the servo to even move and after a couple weeks of fiddling around at lunch and a couple blown voltage regulators today I was finally able to get it to go up and down. The problem is that it is backwards down g code makes it go up. Using z+ end stop on the arduino shield as my pwm servo control

I am using grbl-plotter because is has a great GUI that will be useful in the future because it has a built in g code generator for a imple shapes and txt with out having to go to Inkscape or similar.

The creator seems to only offer a .hex file so I am unable to get into the spindle control file and see if there is something to comment or uncomment to reverse it.

I also tried mi grbl but my stepper motors hated it and would make a horrible grinding sound when moving even with microstepping jumpers set up and my drivers amperage calibrated.

I am not familiar with grbl enough to start from base programming and get the servo set up to work.

so if anyone is familiar with grbl and is willing to make a servo go up and down with m3 and m5 commands i needs some helps