THC : torch height controller
https://github.com/regeg/ArdunioTHC
https://forum.arduino.cc/index.php?topic=282082.0
https://www.cnczone.com/forums/general-cnc-plasma-oxy-fuel-cutting-machines/251266-arduino-controlled-thc.html
http://proma-elektronika.com/index.php/en/products/thc-torch-height-control/compact-thc-150
https://www.hypertherm.com/fr/learn/articles/torch-height-control-for-plasma-cutting/?region=EMEA