Wiring Chinese GRBL Board to 80W CO2 PSU

Hi Guys!

I am new to the forum and laser engraving in general. I am "in my mind" 95% complete on a custom CO2 laser build.

Using a Chinese GRBL board, I have managed to configure setting, calibrate axis, align mirrors etc. The board does not have a 5V PWM output per se, the port is advertised as a "Servo" port, but measuring the V output when running a test cut (with laser PSU deactivated!!) the PWM pin puts out 4.8V when power in Lightburn is set to 100%, 2.4V on 50% power and so on, so I am making an assumption that this should work?

I have managed to test fire and run the laser with a pot and switch, with water protect hot wired. MY NERVES!!!! I will attach the current wiring as reference.

I would like to install a flow switch, door switch and additional safety/E-Stop switch on the front panel that can be slammed at any moment. I am a bit lost when it comes to the wiring though, and would prefer not to resort to trial and error on this one. I am hoping that someone here can offer some advice.

Please let me know if more information is needed. I will also attach an image of how I think this should be wired.

Thanks!

Can’t see images. I don’t think this site allows new members to post photos
I have a home built system. Initially went with Mach3 then switched to DSP controller which is the way to go.
I would get the laser working first. Absolutely need to have water flowing even for test. I would build a simple circuit that drives the PWM signal. Could be a voltage divider or output from an Arduino.
Plan to drive it under 1 volt then work your way higher. Having a power meter is important. You don’t want to overdrive the tube.
Then get the controller working not to exceed the voltages from your testing.


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Hi Dean, Thanks for the advice.

I would like to end up with a DSP, but budget dictates that I use the GRBL for now.

Yes the laser is working when using a potentiometer and switch, and yes I have water flow, installing the flow switch tomorrow for extra level of safety.

If you need high speeds on X axis, use GRBL port on STM32F103 (aka. BluePill).

Great, not sure what help you need. Just connect the switches in series. Each switch stops the beam but the machine keeps going.


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