Finally I’m building my 3D printer right now.
At the moment I wonder about the fitting for the two hotends… and while I was wondering, I thought of adding a laser.
If there a good way to connect 2 extruders as well as an laser to Ramps 1.4?
Or do I have to manually switch between one extruder and the laser diode?
I’d prefer to keep without mechanical switches so I might be able to print an object with two extruders as well as laser-engrave it without changing any switches…
If You’re building Your first one Yourself, I strongly suggest starting with as simple as design as possible until You have a working one. You will encounter various issues and adding multiple extruders or replacable heads will probably make You regret or maybe even retire… You can always add these features later. Keep it simple…
If you have 2 hotends, you will have 2 extruder motors. You are talking about gping from 2 things to control to 5 or more. If you do end up trying the laser thing, remember that laser can blind people and put it in a case that only lets light in and out through specially coated glass or plastic (or whatever) that will block the laser light. You will need an air assist or the laser and a cooling fan for the laser too. You may have power concerns when using both hotends and a heated bed. Good luck calculating yoir power requirements and figuring out your safety precautions. I do not know the ramps board, so I have no idea there.
@Zohar_Karabelnik I’ve built a cnc millingmachine based on an Arduino using GRBL some time ago.
So far I already know all the basics and do my best to avoid mistakes by searching solutions before problems occur 
At the moment I have one extruder. But I want my fitting to be prepared for a second one and the laser. As I do have to mill my fitting anyway…being well prepared will save a lot of time later
@NathanielStenzel I already have safety goggles for the wavelength of my laserdiodes.
But I’m not going to activate the laserpart (if it’s possible to use it with Ramps 1.4 in a way I like it) before I built a housing with safety switches that disable the laser when opened (I already have done so on my FabScan Pi - even if the weak red-line-laser isn’t half as dangerous as the 1000mW UV laser I’m going to use with this 3D printer…).
I’ve seen people using the laser on the D9 output instead of a second extruder. Using a switch to change between extruder/laser might be the easiest way…
But I’ll see what I can to when I setup the firmware.
A single pin would be enough to drive a pnp and a npn transistor to
switch between extruder/laser.
Or a bistable relay…
First I have to see if there are any pins free to use and how to control them using marlin firmware…
You will be going with a cartesian style, right?
Yes, it’s a selfmade design similar to Prusa i3…