@Arthur_Wolf
So something like this:
pin 1.3 (in the EXP 1 group of pins) to GND on my PSU
GND on the X5 to IN on my PSU
Then in my config change “#laser_module_pin to 1.3o”
Edit: Also, will this setup allow a pot?
You might justifiably be skeptical of this cause I have not tested it since I have been waiting to see the LPS internals.
Now that we have a glimpse the internals of the LPS as I suspected the Pot biases the current in a diode on the transmitter side of a opto-coupler which on the receiver side adjusts the DF of the LPS internal PWM. The other controls grnd the transmitting diode on similar opto-couplers to enable disable the internal PWM of the supply.
So putting a level shifter and pwm IN creates a complex circuit and the current in the power control opto-couplers transmitter depends on the position of the pot and the PWM setting from the controller. To my thinking using IN does not provide predicable control.
All we should have to do is connect an “Open drain” to the L pin. The below picture shows my wiring soon to be tested. I plan to use P2.4 as the open drain running grnd true.
I pick it up on the board edge connector for P2.4 and grnd on the “power in” connector two to the right.
The pot can be left alone and it will still set a power limit. However I expect the real power will be the product of the two settings.
So set the pot to 50% power and the PWM to 50% power and you get 25% power.
I don’t know anything about when the smoothie outputs its PWM I assume if a job is not running it is High. I have also heard there is some kind of reset glitch problem.
missing/deleted image from Google+
Here is the PS end of my PWM setup.
Also using a level shifter on the L pin still seems unnecessary to me since the pin is connected to the cathode of a LED and just needs a grnd so the LED can turn on the opto’s receiver and in turn the LPS.
BTW consider that the L pin is the only connection between the Nano and the LPS on a stock K40.
missing/deleted image from Google+
I tried this: pin 2.4o (in the EXP 1 group of pins) to GND on my PSU
GND on the X5 to IN on my PSU
And I have the same issue. Whenever the board is connected to the laser in this manner the laser itself won’t fire manually. Once I disconnect either the ground or the 2.4 pin the laser will fire.
It will, however, fire if I have it set up through the shifter (5v, L, G).
I ended up going back to using the shifter and 5V, L, G. I had moved to the other setup because LightObject seemed to think using those pins was a bad idea, but it works, so I’m going with it.
@K1111 I’m lost … you connected 2.4 to gnd, and gnd to IN??? if that is correct that will not work.
Is it all working now including the current adjustment. Do you have a pot connected?
@donkjr Correct. I followed this post: “So, you need to use a free GPIO pin ( a pin that has nothing on it like pull-ups or pull-downs, which I don’t know which that would be on an azteeg ) that is also a PWM pin.
Then you connect that pin to GND on the PSU, and you connect GND from the Azteeg to the IN pin. Then you set that pin to be Open-Drain ( change 1.30 to 1.30o or 1.30o! for example ) and it should work.”
I have it working now using the level shifter and k40 style setup. The new pot seems to have made a difference. I’m cutting fine, but so far it’s not looking like I’m actually getting any PWM when rastering. I’m testing that as we speak.
@K1111 when you get a minute I would appreciate a diagram that shows how you are currently wired… cause I am lost 
@donkjr I have it done just like this: http://chibidibidiwah.wdfiles.com/local--files/blue-box-guide/k40SmoothieWiring4.png
but I had to connect ground to both sides of the shifter to get it to work.
is this the level shifter you have used?
@donkjr Here’s the one I used. I think it’s a straight knockoff of the SparkFun shifter because it uses the same description. XCSOURCE 5PCS IIC I2C Logic Level Converter Bi-Directional Module 5V to 3.3V TE291 https://www.amazon.com/dp/B0148BLZGE/https://www.amazon.com/dp/B0148BLZGE/ref=cm_sw_r_cp_api_hgHbybPAD8CN6