NEJE N40630 lasermodul with Duet Wifi

Pascal 0 · 18 Sept 2022, 12:11

Hi folks,

I'm currently working with a small 500mv laser engraver. Good enough for some smaller parts, but looking for an upgrade.

I've found the following device on Amazon:

Amazon Link

As far as I know, I can't drive anything else than my small laser directly via the Duet Wifi,
but this Laser comes with an extra device:

Is it possible to attach this device to the duet Wifi directly to run the laser?

Thanks in advance for your help.

TQKez 0 · 18 Dec 2022, 07:34

I also need some clarification regarding the Neje line of lasers.
I got the E40 which is higher output but the same PWM configuration.

I followed the instructions here, including building the board.

https://duet3d.dozuki.com/Wiki/Laser_PWM_control

But the PWM signal doesn't seem to work.
It's unclear whether the board is actually necessary with this module. The wiki page says the Duet Wifi 2 won't be able to drive the laser PWM directly, but it does not state why.

According to the Neje docs, the PWM signal can take anything up to 12V, but the 'ON' state is activated by anything over 2.5V. So in theory, a 3.3V, 5V, or anything up to 12V should just work the way I understand it.

Does this mean the board is unnecessary and we can drive the Neje PWM directly from the Duet board?

https://neje99.com/tutorial/how-to-use-laser-modules.html
https://neje99.com/faq/how-to-make-laser-module-work-with-your-control-board.html
https://neje99.com/faq/about-pwm-signal-specification.html

Thanks in advance!

o_lampe · 18 Dec 2022, 07:59

@TQKez-0 said in NEJE N40630 lasermodul with Duet Wifi:

Does this mean the board is unnecessary and we can drive the Neje PWM directly from the Duet board?

I would run the laser with this board, because it has an test switch and status LEDs.
But you can run the laser without it. (There is also a laser driver module, you can't remove that)

I'd use a 5V fan port to fire the laser, or if you run the Duet board with 12V, you can jumper the fan port to 12V too.
But running the steppers at 12V reduces their possible max. speed, which might be unconvenient during laser engraving. So I recommend the 24V/5V setup.

TQKez 0 · 18 Dec 2022, 21:14

@o_lampe

Sorry, by 'board' I meant the circuit containing the 74HCT02 Quad NOR Gate which is said to be necessary in the Duet Wiki.

I'm definitely using the Neje board with the LED and test switch. It just doesn't seem respond to any PWM changes when following the instructions in the wiki.

I'm running the Duet at 24V as this machine is usually set up as a CNC and its better for the steppers.
Then I have a 24-12V buck converter powering the laser which works fine in test mode.

@o_lampe said in NEJE N40630 lasermodul with Duet Wifi:

I'd use a 5V fan port to fire the laser, or if you run the Duet board with 12V, you can jumper the fan port to 12V too.

So the Wiki says to use heater3 and I've seen other recommendations to use the heater pins for PWM.
So you would say use a fan instead?

Thanks.

TQKez 0 · 19 Dec 2022, 03:04

Actually I think I figured it out now. Works fine without the 74HCT02 board.

Was a little confusing as there are some outdated threads here and the wiki needs updating.

For testing the laser PWM, M452 laser mode with M571 to fire the laser as per the instructions in the wiki doesn't seem to work.

So for anyone coming back here, this works for Neje lasers, with external 12V power, and the laser PWM connected directly to ext.heater3.

Board: Duet 2 WiFi (2WiFi)
Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 3.4.1rc1 (2022-05-03)

In config.g

;M452 C"exp.heater3" R255 F500  ; Laser Mode (disabled for testing)

;Setup laser for testing on heater3 pin, PWM frequenxy 500 (this number isn't too important for this laser)
M950 P7 C"exp.heater3" Q500 ;

Testing examples.

M42 P7 S0.01	; Test laser at 1% power. This reads 001 on the Neje LED display.
M42 P7 S0.10	; Test laser at 10% power. This reads 010 on the Neje LED display.
M42 P7 S0	; Turn off laser. This reads 000 on the Neje LED display and shuts down the laser and fan.

Once happy with PWM is working properly, swap to using real laser mode.

M452 C"exp.heater3" R255 F500  ; Enable Laser Mode.

;Setup laser for testing on heater3 pin, PWM frequenxy 500 (this number isn't too important for this laser)
;M950 P7 C"exp.heater3" Q500 ; Test mode (disabled)

With laser mode enabled, the laser should fire automatically with G1 commands with S parameter setting laser power.

o_lampe · 19 Dec 2022, 08:24

@TQKez-0 said in NEJE N40630 lasermodul with Duet Wifi:

So the Wiki says to use heater3 and I've seen other recommendations to use the heater pins for PWM.
So you would say use a fan instead?

It's only a small signal you want to switch on/off. A heater FET is way overkill for this task.
Although it will work, it switches probably slower than the fan-FET and it is only recommended if the Duet board runs on 12V too.
Otherwise the laser driver sees 24V on the PWM pin...not funny.

The fan-FET can be jumpered to 5V, no matter what voltage the Duet gets.