HI,
Anyone here using smoothieware to control laser. I need help setting up an external laser fire switch and a potentiometer for controlling power when doing testing and alignment. I made a connection diagram. Will it work without messing my smoothie board?
Thanks
@A.J
That’s a CNC shield, right??
I’m using a smoothie board http://smoothieware.org/
My first laser setup was like this, except for CNC shield I used G shield 
Yeah
I configured everything as per the document but it doesn’t say anything about adding pot to it
I made a diagram but think it may mess up with smoothie
See first comment
Now I think this one will work, have to try it
n order to control the power of the laser tube, the laser PSU reads a PWM signal as it’s input.
Please look at the datasheet for your PSU to know which connection that signal is wired to.
From the Smoothieboard, you need to connect :
One GND pin to the Ground connection on the PSU
One of Smoothie’s PWM pins to the PWM input on the PSU
Both Ground pins are easy to find, and the PSU input you find in the manual/datasheet, now all you need is to find a PWM pin on the Smoothieboard.
There are 6 of them, but 4 of them are used for the step pins for stepper motor drivers.
Those for alpha and beta you won’t be able to use as you use those drivers to control the X and Y axes.
Depending on whether you have a Z axis, your gamma axis step pin could be used. It is labelled ST3, on the JP12 header, near the M3 stepper motor driver.
You probably do not use your delta ( M4 ) stepper motor driver on a laser cutter, so that pin can also be used, it is labelled ST4 on the JP15 header near the M4 stepper motor driver.
The other two are found near the microcontroller and the MOSFETS, on the JP33 header, and are labelled PWM0 and PWM1.
Choose which you will use, all have a GND header close-by ( all are unlabelled ) to make it convenient for wiring.
Now you need to find which GPIO pin/port number corresponds to the PWM pin you chose, so you can tell Smoothie which you’ll be using in the configuration file.
Pin number for configuration Label on the board Comment
2.2 STP3 Only if you are not using a Z axis/the gamma driver. Make sure you set gamma_step_pin to the “nc” value. The unlabelled pin in JP12 is GND.
2.3 STP4 Only if you are not using the delta driver. Make sure you set delta_step_pin to the “nc” value. The unlabelled pin in JP15 is GND.
2.4 PWM0 Only if you are not using the first small MOSFET ( X8 ). All pins of JP10 are GND.
2.5 PWM1 Only if you are not using the second big MOSFET ( X15 ). All pins of JP10 are GND.
You cannot directly control the PWM signal with a pot to your power supply. How do you intend to use the pot? In an and or OR configuration?
I’m not controlling the pwm signal using pot. My intention is to generate low power I’m using the pot to provide a variable voltage(0-5V) to IN port of PSU so that I can control the laser power.
But some people says it’s not possible to have both pot and PWM control.
I think my new setup would work. Here by using an SPDT switch I can chooose pot contol when testing and PWM from smoothie when running via software
That instruction for setting up a pwm pin , my pwm pin from smoothie is pin 2.3 (see picture) and I already done that .
I’m trying to set up a pot along with PWM from smoothie
Your schematic should work in theory. It is true that it is an OR issue. PWM or POT but not both. Good luck on your project and keep us up to date on your progress.
Thanks, and I will
I have a doubt abut one smoothie configuration
Can you tell me how !^ configuration make a pin active low?