Infor:Want to connect a firmware controlled FAN to RAMPS board directly when you build or upgrade your printer with/to DUAL-EXTRUSION (2 extruder) including a heated bed, but found that all the output ports (D8,D9,D10) will be used?

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).

Features:

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)

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")