I was given a broken1990’s embroidery sewing machine for parts. It has X, Y axis system with stepper motors, gears and belts. I also have a spare MKS Robin Nano V1.2 control board. I envisioned setting up a firmware development system where I can easily at a desktop, write and test control board firmware.
It took me a few hours to wire up motors, end-stop switches, adding Z axis, mounting control board and display. Instead of doing a custom Marlin FW build. I used settings available in Robin Nano firmware V2.0.3.6, via LCD setting menus, and config.txt for end-stop plug setting, for X-max end-stop.
I did continuity checks with multi-meter, powered up and set stepper driver reference voltages to 0.5V. I then used motion settings to jog motors set, motor directions, home directions and end-stop settings, and step settings. My android phone, 3D Fox app via OTG USB cable was used to send M119 and receive end-stop status information. I could have used Pronterface with notebook, but that takes more bench space. After verifying correct end-stop operation, homing was tested, it worked! It is important that X is homed before Y, to reach Y end-stop at X-max. I found that using Robin_nano35_cnf.txt settings to disable X_min plug, and enable X_max plug, enabled LCD menu item for X-max end-stop. Modified Robin_nano35_cnf.txt is placed on SD card, and controller board powered up, it reads file and changes suffix .txt to CUR for current setting. I see it in a way similar to Klipper, to make many configuration changes. What is lacking is good documentation, and FW source code from MKS.
I then added a low cost Z axis slide, added Z end-stop using a H22A optical vane sensor. This was used to lift pen for use as a plotter. I then used FreeCad to make simple geometric shapes of 0.2mm layer height, sliced with Cura to generate Gcode, and modified by adding a few G0 Z commands to raise and lower pen as necessary for home, and plot requirements.
My long term plan is an attempt to add enhancements to Marlin FW.