The goal of the machine is to put music on a vinyl record. for that the PC sends the sounds in the sound card, then to the mixer, then to the amplifier. the amplifier is connected to two speakers that make a diamond vibrate.
The electronic board allows with an LCD screen to:
Commandant a step motor,
Send and receive MIDI commands,
Order a servo motor (for the engraving head position),
Receive the information from sensors,
I still have a lot to learn on the lathe cutter but the result is pretty good for an homemade machine so I share a video of my project.