Reprap Ramps1.4 RRD Fan Extender

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Fan1.jpg Fan2.jpg

If you build or upgrade your printer with/to DUAL-EXTRUSION (2 extruder) including a heated bed all the output ports (D8,D9,D10) will be used. In this case there is

not option to connect a firmware controlled FAN to RAMPS board directly. However in Sprinter/Marlin firmware there is an option already (Marlin: BOARD=34) which

redirects the FAN to RAMPS output D4. But this solution needs a "buffer/driver"in order to work.

The RRD-FAN-EXTENDER is exactly what you need in this case. It is a plug and play solution to mount the FAN for DUAL-EXTRUSION setups with RAMPS1.4. But instead of

adding only one additional output port the RRD-FAN-EXTENDER is equipped with 2 PWM controllabe channels(D6/D11). The second channel can be used for another fan

(e.g. to cool the stepper driver) or for adding light control (e.g. add dimmable LED light to your machine).


  • max 20V
  • 2 (PWM controllable) channels (D6/D11)
  • max 0.5A per channel (enough for a really big fan)
  • flexible output voltage (you can connect the RRD-FAN-EXTENDER to 12V,5V,... in order to support the output voltage you need)
  • each channel has a fly back diode
  • easy setup (plug and play)
  • already supported by Marlin firmware (choose "#define MOTHERBOARD 34")
  • easy to adapapt to other firmware (e.g. Sprinter: just change "#define FAN_PIN 6" in "pins.h")



You need Marlin firmware v3 or newer. If you are using older firmware, you must re-flash your board.

The latest Marlin firmware is available here:


Test the Editing Reprap Ramps1.4 RRD Fan Extender

Hardware required:

-Ramps 1.4

-Mega2560 board

1.Upload Test for Editing Reprap Ramps1.4 RRD Fan Extender to your Mega.

void setup() {

 pinMode(11, OUTPUT);
 pinMode(6, OUTPUT);

} void loop() {

 digitalWrite(11, HIGH);  
 digitalWrite(6, LOW); 
 digitalWrite(11, LOW);
 digitalWrite(6, HIGH);   


2.Connecting follow this picture:


3. Power up ,two fans will take turns to rotate

How to buy

Click here to buy Reprap Ramps1.4 RRD Fan Extender