Notes
How to connect TTL laser to Woodpecker CNC
Pin11 (Spindle_enable) is a PWM pin. You wire the TL(TTL_Low) to ground of Arduino and TH (TTL_High) to Pin11 (Spindle_enable) and you can dim it by feeding it an S command from zero to what ever you have $30 at. Be careful - on old board shields (v3.0 and older), the z_Limit and Spindle_enable pins are swapped. Because the z_Limit is held high by the arduino, it may fire the laser and keep it on.