wiring advice: Ramps 1.4 with Fan, LED, z_probe switch

My hot end will have some LEDs to light the print area and a fan for the Jhead. In Repetier, I see a slider for fan speed.

Can someone explain how with Marlins, I can control a Jhead 40mm fan and 3 little leds?

What pins.

I also have a microswitch to z_min pin for auto bed leveling.

I don't know enough about lectronics. Am I correct I do not need to wire 3 seperate grounds for the LED/Switch/fan, I could have all three wired together and only the positive wires to the RAMPS?

I'm trying to have less wires.

Anythoughts.

Thanks

Alex

The simple approach is to not wire any of the "extra" stuff to the Ramps at all. Hook the fan, and the 12V LED lights straight to the power supply. Everything turns on and off when the power supply goes on and off.

Not a bad idea. I think it is prefered to not use the fan on the first layer or to to help adhesion. then fan. It would be nice to have software to control the J-head fan.

If you are going to run multiple fans all under software control, you will need to get an add on fan board and connect it up to the aux pins.

I see very little advantage to running the J-head fan with software. You very much want it to cool the head all the time.....

I'll leave the fan discussion to the experienced folks.

As for the LEDs, I'd wire them in line with the heater in the print head. You would need to make sure they can handle the power that will flow through them, but then there are no wires leaving the extruder assembly.

If you absolutely want separate light control, then run a pin from your RAMPS board (I'd grab a spare one from AUX-4) up to your extruder, into the positive on your LEDs. The negative on the LEDs then runs into whatever resistors you need to add, and then run the other side of the resistors to the ground wire from anything in the extruder. I would recommend running the LEDs in parallel, and only using one resistor.

There is actually a pin assignment already in the MARLIN pins.h (I'm assuming you are using MARLIN). Just set the correct pin number.

Then, you need to find where the print job is controlled from (Marlin_main.cpp, I think), and add a line of code to send that pin high when you want the lights on, and a line of code to pull it low when you want the lights off. (Uncle_bob, do you happen to recall where the job start and stop subs are located?)

The heater pulls 10 to 15 amps. The hot end pulls about 3 amps. You very much do not want to run that through an LED.

Stay away from pins.h unless you really need to do something odd and you know what you are doing.

Interesting. I* diod like the idea of the LED attached to the hot end. But then again the PMW would make them flash on and off occasionally.

At the moment I'm trying to physically wire (solder, connectors) a z-probe micro switch, the 3 dollar store leds, and a 12v fan. I'm guessing the LEDs are 5v. I will need 6 wires to the Ramps.

I don't have a heated bed. casn the fan be connected directly to the RAMPS where the 12v heated bed would go?



Thanks

The fans are 12V gizmos. The LED's need resistors in series with them to limit the current. You size the resistors based on the supply. If you have string LED's they may have resistors in them already for some unknown voltage.

If you hook stuff up where the heated bed or other stuff goes, it will not be turned on. You would need to tell the MOSFET's to enable (or disable) the supply to those pins.

The big issue is stuffing a lot of small wire into those screw terminal blocks. They don't like that very much at all. The wires will eventually fall out. It's a real hassle keeping everything going that way.

Your Z switch will need to be wired to the Ramps pins that "look" at that function.

Edited 1 time(s). Last edit at 12/21/2013 06:06PM by uncle_bob.