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 https://reprap.org/forum/read.php?219,281880,281880#msg-281880 Sat, 18 Jul 2026 21:02:29 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?219,281880,283100#msg-283100 https://reprap.org/forum/read.php?219,281880,283100#msg-283100
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.]]> uncle_bob RAMPS Electronics Sat, 21 Dec 2013 18:05:33 -0500 https://reprap.org/forum/read.php?219,281880,283065#msg-283065 https://reprap.org/forum/read.php?219,281880,283065#msg-283065
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]]> disneytoy RAMPS Electronics Sat, 21 Dec 2013 15:58:05 -0500 https://reprap.org/forum/read.php?219,281880,282825#msg-282825 https://reprap.org/forum/read.php?219,281880,282825#msg-282825
Stay away from pins.h unless you really need to do something odd and you know what you are doing.]]> uncle_bob RAMPS Electronics Fri, 20 Dec 2013 23:48:34 -0500 https://reprap.org/forum/read.php?219,281880,282701#msg-282701 https://reprap.org/forum/read.php?219,281880,282701#msg-282701
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?)]]> BlackDragon RAMPS Electronics Fri, 20 Dec 2013 15:39:44 -0500 https://reprap.org/forum/read.php?219,281880,282515#msg-282515 https://reprap.org/forum/read.php?219,281880,282515#msg-282515
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.....]]> uncle_bob RAMPS Electronics Fri, 20 Dec 2013 08:12:14 -0500 https://reprap.org/forum/read.php?219,281880,282356#msg-282356 https://reprap.org/forum/read.php?219,281880,282356#msg-282356 disneytoy RAMPS Electronics Thu, 19 Dec 2013 23:14:59 -0500 https://reprap.org/forum/read.php?219,281880,282342#msg-282342 https://reprap.org/forum/read.php?219,281880,282342#msg-282342 uncle_bob RAMPS Electronics Thu, 19 Dec 2013 21:44:02 -0500 https://reprap.org/forum/read.php?219,281880,281880#msg-281880 https://reprap.org/forum/read.php?219,281880,281880#msg-281880
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]]> disneytoy RAMPS Electronics Wed, 18 Dec 2013 20:49:36 -0500