Hotend cooling fan control?

Hi,

I have a 2 wire always on hotend cooling fan. Its connected to the broken out 12V pins on my Ramps near the blade fuses. Now I would like to control this fan via one of the broken out pins on the ramps which would be easy if I had a 3 wire fan where I connect the signal wire to an analog pin, but how to a manage the same for the 2 wire fan. I would need to build a switch with two pins somewhere. Did someone ever do something similar?

Cheers

Check this out [start3dprinting.com] where this guy claims he wired into the D9 ports on the ramps board and was able to control the fan with G-code!!!

There are also 2 pins (Behind the 2 yellow packets) that are for the extruder fan. M-Code turns your fans on and off. "you can send a M106 S[0-255] to set the speed of the fan…. 255 being the fastest, and 0 being off."

Edited 3 time(s). Last edit at 02/11/2015 07:54AM by Chaser30.

D9 is the model cooling fan and its controlled by the m106 commands.

I could of course trigger an external relay with a custom command via some of the aux pins but that seems work intensive but I wonder if Ramps has some controllable 12V pins natively.

Edited 1 time(s). Last edit at 02/11/2015 08:27AM by sungod3k.

there the 2 pins that are behind the yellow packets that are for the extruder fan, to run 2 fans for dual extruders i know you can get a splitter board that attaches 2 fans and then connects to the extruder fan pins on the ramps board. the mcode is entered into the gcode dependind on what settings you enter into the software eg repititor and speed of fan is controlled by voltage throgh the board and software. i use the extruder fan pins and has only 2 wires with no probs you can test with mcode, and when you set up fan settings in software, search for the mcode to ensure its in the gcode

Edited 1 time(s). Last edit at 02/11/2015 09:27AM by Chaser30.

Yes Im using the pins behind the "package" for the extruder fan but to my knowlegde you can control this one with gcode. Only the D9 model cooling fan can driectly be controlled to my knowlegde.

I found this here [neverstopbuilding.com]. this reuqires a relay but is exactly the functionality I need.

To me the extruder fan must be on at full speed anytime. May I ask why you want to control that fan ? Is it for on/off purpose only ?

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Yes on off only. I dont want to have to walk across the room all the time and disconnect the printer physically just because the extruder fan is so loud.

Ok, what about using a simple $1 relay ? you can use direct PSU 12 output and pilot it thru any 5v output on the ramps, like aux or servo outputs :


Edited 1 time(s). Last edit at 02/12/2015 05:47PM by Zavashier.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)