Adding cooling fan questions

I just recently switched from Sanguinololu to Ramps 1.4. I have everything up an running except cooling fans. I currently have two 5v 150ma fan mounted on my extruder and would like a third for my case. As far as I can tell, the extruder fan can be controlled by pin 9 but I don't have any idea how to connect them up on the shield. Do I need to add a mosfet to power pin 9 for fans? Is there a direct 5v access to the power or do I need to step down the 12volt from my power supply?

Thanks in advance
Kassie

d9 is the coolingfan.

I think the answer is that ramps 1.4 has a green external header for d9 on the side with all of the other power connections. That is either 5 or 12v, and it has already run through a mosfet so that it has enough current to properly run a motor or a heated bed.

If you were to connect it directly to the d9 pin of your arduino (as opposed to the d9 port on the ramps shield) then you would not end up with a spinning fan. You could end up with a dead arduino pin.

as for 5v/12v, it depends on your fans. One last thing is that it may be easier to just add a direct line from your power supply, and not have to worry about switching them on and off with gcode. Add a molex connector and just plug them in!

_Ross

I have a similar question as Kassie...
But a little varied, and more specific, I guess.
I currently *have* a 12v fan running on the d9 pin, and have configured custom buttons in Pronterface to allow me to nicely turn on or off as needed. Just how I want it.
I now want to power - from RAMPS - a small pair of 5v fans (stolen from a dead laptop), to be used to cool RAMPS itself. I would also like to configure a custom button in Pronterface for me to control them.

The "servo" accessory headers on RAMPS 1.4 show as being 5v. Can anyone clue me in how I could utilize these headers for this purpose? I can add the pin headers no problem, and the pins themselves are easily enough identied, but is there something in firmware I must enable to actually use them? And, what would the gcode be to "enable" / "disable" a specific pin from a custom button?
Greatly appreciate any assistance! TIA

For anyone else maybe looking for something similar to what I was trying to get worked out :

M42 is the "magic bullet", so to speak.

[captain-slow.dk]

That article describes implementing it in Sprinter, but it al;so available in Marlin.

So, in my case, I wanted to utilize pin "D4", a 5v "servo" pin on RAMPS to power a couple of little laptop fans.

I created a pair of custom buttons in Pronterface, one "ON" - one "OFF" and use :

M42 P4 S255
- and -
M42 P4 S0
respectively.
Exactly what I wasn't able to sort out on my own, and works perfect.

With ramps 1.4, there is a screw terminal (D9) between the hotend and heated bed outputs. It's a 12V output so you will have to use a 12V fan. This output can be turned on by sending an M106 command in the gcode and stopped with M107.

Example:

M106 S255 //turn on fan at %100 PWM
G4 P1000 //pause for 1 second
M107 //turn off fan

If you want a fan to be on whenever the hotend is on, just attach the fan wires to the D10 screw terminals along with the heater wires. Just make sure your polarity is correct for the fan wires.

If you want the fan to be on all the time, I use one to cool my ramps heatsinks, just solder a molex connector on the wires and connect it directly to the power supply.

With Marlin and Ramps 1.4 I needed to swap a couple of pin assignment in pins.h for board type 33 in order to use D9 for a 12V fan. This basically disables the high-current extruder2 heater in favor of a PWM fan that can be enabled with the fan button in Repetier.

Before:

#define FAN_PIN 4
#define HEATER_1_PIN 9 // EXTRUDER 2

After:

#define FAN_PIN 9
...
#define HEATER_1_PIN 4 // EXTRUDER 2

I'm sure there's some other, cleaner way to do it but this worked for me.

Charles

Yup.
Just what I did, plus the M42 codes to control P4 for my 5v fans. Works perfect.

Can you post how you added the buttons in pronterface? if possible include the code?

thx

just click the "+" button to the right of the existing buttons to add a new one.

fan on = m106
fan off = m107

you can also add s(0-255) after m106 to PWM the fan

eg: m106 s150