3.5 Watt Chinese Laser (August 2018)

Mostly Printed CNC - MPCNC Advice
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I didn’t really want to start a new thread since it seemed like all the information was already available, but in different forum threads and website posts. However, I’d like to make sure that everything is up to date, and was told making a new thread would be a better idea than asking this in an existing thread, so no problem.

 

Picked up an Eleksmaker 3500mw (3.5w) blue-violet laser from Banggood. It has 12v TTL modulation on its attached (separate from the module) control board, and the power is pre-wired into a female DC/laptop power adapter, with the power brick separate. TTL module has no wires currently, looks like some kind of Molex connectors.

 

The website mentions that on the RAMBo, the board I am using, the current laser mapping is:

When using a laser or a PID controller the Pins on MX2 are available.

45 (PWM), your laser pin or PID speed. Controlled by M3

31 Laser or PID, enable, Controlled by M5

23 not assigned yet, Shared with YMAX


Pictured is the pin area, called MOTEX or motor extensions.

So, the scenarios from this:

  1. I can externally power the laser with its power supply. Then I could wire the TTL port on the control board to the RAMBo. Where would that go? Positive to pin 45, negative to where? Ground; the negative pin in the picture; or elsewhere?
  2. I can power the laser through the RAMBo. Cut the provided adapter, then mount the wires in a connector and attach them to the +/- in the picture? If that is power, of course. Then the same problem arises for the TTL, where exactly to connect it.
I know that PWM and TTL are used interchangeably even though they are different, or at least that's what some quick research turns up. Another forum thread from quite recently involved someone hooking their laser up and accidentally dithering the output, so performing PWM through TTL or the other way around, just rapidly turning the laser on and off instead of the more desired power level changes (0-255).

 

The guide for the Leo Laser - is any of it also applicable?

 

Do any changes need to be made to the firmware? Is the updated Marlin posted on August 1st, 2018 (Marlin 2.0) any different in regards to making said changes? I would probably be updating the machine since my firmware is from December, 2017, and the only available option linked is the official Marlin, as the Allted branch is from August, 2017.

 

Scenario 2 is probably less preferred since plugging the laser input power into its own port causes less power to have to flow through the RAMBo. Just interested in turning the laser on/off and changing its power level. Is any information from above still accurate?

Thank you, and please pardon the disorganized format. Asking questions seems harder than writing a detailed process.

 

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Can’t help you with the rambo part as I use a ramps board, but I have a EleksMaker 3.5W and I would assume it is similar to yours if not the same model. My laser has a 12v power supply, but the TTL signal is 5v. I use the brick power supply to run the laser, although I routed the positive side of the 12v cable through a dedicated switch to make sure the laser doesn’t fire unless I am expecting it to. Then a signal control cable is run from the + & - pins of the laser driver back to the ramps board.

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