PWM control of laser module not working

firex726 · 31 Mar 2020, 04:09

Hi All,

I have a Wanhao duplicator i3 v2.1 (Marlin), I have a small laser module I can hook up directly to the PWM controlled fan connector and using the M106/M107 commands I can control it's intensity and use it for engraving.

I have been trying to adapt the same setup for my Hypercube Evo and Duet2Wifi board but can't seem to get the PWM (if that's what it is) to control the laser correctly.

The power leads of the laser control board attach directly to the fan connector and on the Wanhao it just works, but the Duet it is either 0% or 100%. Even when trying to manually send the M106 S### command it'll respond in binary function.

Wanhao

M106 S2

Very faint light, barely see with lights on.

Duet

M106 P1 S2

Full blast would burn hole in wall

 ; Fans
M106 P0 S0 I0 F500 H-1               
M106 P1 S0 I0 F500 H-1

droftarts · 31 Mar 2020, 11:35

@firex726 It will depend on the signal your laser module is expecting. Does this guide apply? https://duet3d.dozuki.com/Wiki/Laser_PWM_control
Otherwise, search the forum for other examples of hooking up a laser: https://forum.duet3d.com/search/?term=diode laser&in=titlesposts
It may also be firmware dependent. What firmware version are you on? Send M115, post response. Your full config.g would probably help, too.

Ian