NEJE-like Laser as CNC upgrade

chimaeragh

@mdalacu Are there not any downsides with connecting this way? The laser wiki states you need a specific electronics to attach a laser to the Duet2. I'm thinking you may fry your Duet if 12v from your test board runs back into it.

mdalacu

@chimaeragh I really hope not. The test board underneath the display has an integrated circuit. I think it basically does the same thing as the circuit on the wiki. But I am not an electonist...by any means.
What can I tell you is that after almost 1h of total burning time, everything still works perfectly!

chimaeragh

@mdalacu I hope so. From the wiki... [Laser PWM Control( https://duet3d.dozuki.com/Wiki/Laser_PWM_control)

The circuit diagram for the needed circuit, including protection for shorting of 3v3 line to prevent unintended Laser Power on is shown below.

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I do not think the test board has a 74HCT02 Quad NOR Gate.

FelixH

@mdalacu I don't think they designed the circuit @chimaeragh displays just for the sake of it. I actually build that circuit with TTH components and it has been working great

mdalacu

@chimaeragh @FelixH Maybe someone with more knowledge than us could look at that test board and tell us if it is safe.
The test board has an IC roughly the same size as 74HCT02 underneath the 3 digit display, but I can not tell which one. I don't what to disassemble the board since it is working just great.

chimaeragh

@mdalacu Upon further investigation, I am certain the 74HCT02 Quad NOR Gate is required to prevent shorting of the 3v3 line and accidentally turning on the laser. I will advise you to get the board if you plan on doing much laser work. It cost me less than $42 to get a batch of 5 of these boards made, assembled and shipped to me at jlcpcb.com

FelixH

@mdalacu said in NEJE-like Laser as CNC upgrade:

@chimaeragh @FelixH Maybe someone with more knowledge than us could look at that test board and tell us if it is safe.
The test board has an IC roughly the same size as 74HCT02 underneath the 3 digit display, but I can not tell which one. I don't what to disassemble the board since it is working just great.

mmm... I do not need such information. As I said, I made myself the Duet recommended board for using lasers and it works as advertised...