Laser TTL turn on/off

Hi Guys,

my MPCNC is up and running now.

Time for some add-ons

I have a 2W laser laying about… so I made a mount for it.

Hooked up the 5V TTL connection to pin 44 and GND… But laser does not turn on.

As I usually mill from SD card, I’m trying repetier host to turn on / off the laser using the M3 / M5 command.

But the state of pin 44 does not change…


What am I doing wrong?




Try to check
M3 o200
M42 p44 s200


I don’t know what board you are using, but…

IF it is RAMPS1.4 and you have remapped the D9 fan output to pin 44 (this is the way I use it)…

use M106 Sxxx to turn the laser ON at intensity xxx, and

use M107 (or M106 S0) to turn laser OFF

– David

1 Like

After an entire sunday or reading, google searches and reading through the marlin code, I found that, in my case, the M3 and M5 commands controle pin D6 on my ramps 1.4 board.

So I have finally got the laser to fire!!


Thanks for the replies guys

Once I’ve got the laser fitted to the MPCNC, I’ll post a picture.

The mount is printing on my tevo tarantula as we “speak” :smiley: