New to lasers but as you do I thought I can make one of these. Have a 100W tube and am going through the setup with Aurdino and Grbl. 1 thing I am struggling with is finding how to connect either the TH (Trigger High) or TL (Trigger low) to the aurdino. and which command to use to arm the laser. I am using pin 11 for the PWM and so G1 and S code for laser intensity and travel. M4 to set the dynamic travel. Not sure if I should jut be using a switch with a supply to the TH to turn the laser on. Will be bridging the Water protection for now but will look into a flow switch which a could connect through a relay to the TH.