Alternate Pin for Laser Mode on Printrboard Rev D

I have a few printrboard rev D. around and I already blew two of them trying ot use the Fan to control a 3w diode laser. I see in the firmware configuration on Tools you can choose another pin for it. I've tried setting it to first Extruder and Bed but neither seem to send anything out when you do M106 S255 (on full) or M107 (off) or even G1 X1000 which from the config notes on laser mode should turn it on for 1000mm move then off. 

I can power the laser directly with 12v (from printrboard power input which is also 12v) but I want to use the 3rd yellow wire for PWM and let a printrboard pin control that PWM. What am I missing? What alternate pin should I use to control a PWM signal in Laser mode? What are the related gcodes?


  • First is the pwm signal a 5V TTL level input - then you can use any free 5V pin.

    Importnat is that only one feature get the pin assignes so either fan or laser otherwise they might change and overwrite signals.

    For laser PWM is not supported only on/off. You need to add a event for laser intensity setting if you want to use pwm. Otherwise it is only on and off and you need to control power by move speed.
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