C3D and Diode Assistance


I ordered the LE5040 Diode kit from Sainsmart and I have been enjoying it.

I feel that i have already met the limits of what it can handle when doing images/greyscale. At least from what i understand the 8-bit grbl controller it can came with is basically maxed out around 400 instructions p/s so doing a 254 dpi photo can only run at around 40mm/s which is painstakingly slow. After some research it sounds like your laserboard would take me to the next level and improve speeds greatly, but honestly i am not super sure what the best way to hook it up would be. (I just now realized this wont let me upload photos.)

This is a link to to the diode manual that came with the kit:

Essentially the current controller on the machine has a 3 pin cable, red, black and white (i believe the red is 12v, black is ground and white is PWM). This cable runs to a separate board to the laser itself that output to the laser head and the fan on the laser head. The board on the laser itself has its own barrel plug as an alternate way to get the 12V in, there are pictures in the manual. (there are pictures in the manual)

So after that long winded exlpanation of guesstimates here is the ask: can i unplug the 3 pin on the board near the laser, use the 12v power brick with barrel connector and plug it in there for power and just run a single wire to the PWM pin to a certain pin on the C3D laserboard? The main controller just has one x and one y stepper connectors, so also just move those over to this board? And then use the included 24v power brick to power the C3D laserboard?

Or would there be an easier way of running the wiring on this?

Thanks for any help

We just discussed the “why should you do/ not do this” in this topic:

Then I’d recommend the searching of the forum for “diode” to see what has already been discussed.

Start here:

And also read the linked topic there.

You should be able to upload pics so we can see your setup exactly.

I think that will be fantastic. Yes, I have a variety of 12v power supplies. I also have a spare 24v connection off of my power supply from openbuilds. I don’t have the optlasers laser yet, so I would have to look at their documentation to see how many wire control it.

Thanks for the reply, and i did get the notification i can post some pictures. When i get home i take some and add to this.

In the meantime i used my mad photoshop skills to do this:

So essentially the main controller has three wires that connect on the bottom right of this secondary controller that is mounted near the laser.

I don’t know if it would be best to just bypass this board all together and run the leads back to hook in directly to the laserboard if i got it or just add 12v power to this board via the barrel connector on the top right and just run the PWM sign to this, and if I will just be able to run a single wire or would i need to hook the GND and PWM into the alternate pwm.

Also if i can just bypass the above board, hook the laser to this alternate pwm, would there be a place on the laserboard to hook up the fan that sits on top of the diode?


Thanks for any input, i will take actual pics later, but this pretty much illustrates the wiring on this thing, except the 3 pin at the controller.

Thank you,

I did find this picture:

It has a second connector that is 2 pin that is strictly PWM and GND.

If i put the 12 barrel straight into this board could i connect directly to the laserboard, would i use the + and - diode or alternate?

Below are pictures of the actual set up

The 3 wire cable runs from the controller on the back of the gantry to the board mounted near the laser, then a 2-wire connects to the laser and another to the fan.

I am looking upgrade purely for an increase in speed, so i don’t know if it would be best to bypass the board near the laser and have everything direct connect to the laserboard or would it just make sense to utilize this piece as well.

Looking for any guidance to see if the laserboard would benefit me. In essence, doing either greyscale or high dpi work is painfully slow, if i understand it correctly, the stock controller is limited to aprox 400 instructions per second and the below chart is the wall i am hitting in terms of speed, the math may not be perfect but it seems like it holds true. If i do an image at 254 dpi at 40mm/s, then do another at 254 dpi at 100mm/s, they essentially go the same speed, which i believe is caused by my controller.

This little Pika took 4 hours on construction paper @ 254DPi, 35% power, 40mm/s

Looking to order a board if I can get some help on wiring, im not an electrical engineer by any means but i do know my way around a soldering iron. I would be happy to document the process and do a simple walk through if i can get it up a running! Theoretically speaking what would the max instructions per second this board could process?

Thanks for any help!

Just FYI, i found this picture on a different thread on this form:

I feel like this wiring makes the most sense, grounding the 24v and 12v in the same circuit, along with the neg from the “alt pwm”, providing positive signal to the from the laserboard and 12v from the old controller power brick. Shoutout to @bentleya for providing the picture.

I have ordered the board, next step will be to plan out the config info to get it set up.

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