Thanks, Arthur!

I looked through the documentation. One thing that I'm not sure about is whether I can connect the laser directly to the smoothieboard. It's a 2.5W laser so it's using less than 1A if powered by 12V.

Can the smoothieboard control the laser with PWM? Where would I hook the laser to the smoothieboard?

Oh a laser that power definitely needs a laser driver board. That board has a TTL input, which you wire to any PWM pin on Smoothie.

Oh ok gotcha. I was just using my Rambo board to power my laser so I thought maybe I could do the same with the smoothieboard. Is it because the smoothieboard can't do 12V PWM? Or is it just too much current for the pwm outputs?

You can do what you did with Rambo with Smoothie, Smoothie can do 12V PWM ( for example it does for hotends, but it can for lasers ). It's just not how the laser is supposed to be used, current needs to be regulated, that's what the driver board is for, and if you skip it, you'll likely severely reduce the laser's life.

Ooohhhh. I see. So is the fundamental difference between the two methods is that the PWM is tuning the laser on and off and the driver board varies the current rather than turning off the laser so often?

If that's the case, I could see why PWM would reduce the life of the laser.

No it's about limiting current vs limiting tension.

Ok thanks. One last question. I didn't see this in the laser module of the documentation.

I'm going to be using all the stepper drivers because I have a Prusa i3 type printer. So all the pwm pins in the laser cutter documentation will be used.

Could I then wire the TTL port of the laser driver module to any of the pins mentioned in the configuration?

From the configuration file:

Only pins 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 1.18, 1.20, 1.21, 1.23, 1.24, 1.26, 3.25 and 3.26 can be used since laser requires hardware PWM.

Or do I use the TTL pin:

#laser_module_ttl_pin                           1.30            # This pin turns on when the laser turns on, and off when the laser turns off.

But that's confusing because it seems like it's only on or off. I want to be able to vary the power.

Anyway, sorry if I'm asking too many questions but you've been a big help and it's awesome that you're so willing to help the community. Thanks.

You want to use one of the PWM pins for laser control.

It seems my laser has a built in constant current laser driver. I don't think I'll be able to use a TTL driver board with this laser.

I think I'm just going to have to run it off 12V PWM and replace it when it burns out. What pins can do 12V PWM and can output at least 2.5 Watts?

Unless you have a better suggestion. I don't know if I can disassemble this laser and remove the constant current board and hook up the laser module to a TTL laser driver board.

If you want 12V pwm then you need a mosfet that is controlled by a pwm-capable pin, see the pinout page and the documentation on temperature control.