| Other Features | 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 isnot option to connect a firmware controlled FAN to RAMPS board directly. However in Sprinter/Marlin firmware there is an option already (Marlin: BOARD=34) whichredirects 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 ofadding 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).Features: max 20V2 (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 diodeeasy 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")TEST Test the Editing Reprap Ramps1.4 RRD Fan ExtenderHardware required:-Ramps 1.4-Mega25601.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); delay(5000); digitalWrite(11、 LOW); digitalWrite(6、 HIGH); delay(5000); }2.Connecting3. Power up 、two fans will take turns to rotate |