Build Your Own SLA/SLS

Hi guys. I´m from Spain and I´m searching information about building my own LCD UV SLA printer.
I have a million of doubts, but at the moment I only want to solve one.
I want to build it with a rapberry pi 3 conected to a ramps 1.4 and Mega 2560 ( I have someone in house without use) and controll it with nanoDLP software. I imagine the motors and other parts will be controlled by Marlin like an FDM printer, but that it´s not my doubt now (there will be another time for that)
I want to know exactly how the UV LED is controlled ( how and where is connected to turn on/off LED when slicer send to lcd panel the layer ) because that control in origin is in the LCD board, but I don´t know how to find the signal to control and external LED.
This is the only question that stop me to start the project.
Thanks in advance for all and I hope in future I can solve you any doubts.
Thanks again.

I don't know either. I don't think that was ever built into DLP or LCD based SLA control software because the masking ability of those systems was used to block the light. So, in other words, the light was or is always on. Now that LED light is starting to be used, especially with LCD based SLA systems, that would be a good feature request suggestion. Although, I don't think Steve is continuing to develop Creation Workshop so you need to make the suggestion to the developers of NanoDLP.

There is a way to do it though! You can do it with Creation Workshop or NanoDLP. Both of these have a built-in means of operating a shutter mechanism. The reasoning for this ability came into being because of light bleeding through the digital mask with some types of DLP projectors. With early DLP based SLA systems, it was impractical to turn off the light because the light needed to spool up to operating temperature. So, what was devised was a shutter mechanism that was usually actuated via an RC style servo motor.

So, what you could do is use the same method, but instead of operating a servo you can use the same signal to operate a switch to turn your LED off and on.

Thanks for your reply James.
I solved it making a command in Marlin and sending it in the Gcode of the slicers.
Thanks again

Great! I'm glad you got it working like you wanted!