Fan extender for RAMPS 1.4

thingiverse

A small circuit to add a second fan to your RAMPS 1.4 controller. For instance : the first fan is wired to D9 and cools down the print the second fan is wired to the fan extender and cools down the printing head The schematic is the same as on RAMPS board (for D8 to D10). A LED indicates when the fan is running. Instructions THE CIRCUIT The files can be read with Eagle 7 free version (http://www.cadsoftusa.com/) Print the circuit on single-sided PCB, the parts needed are : R1 : 10 ohms, SMD 1206 R2 : 100 Kohms, SMD 1206 R3 : 1800 ohms, SMD 1206 LED1 : SMD LED (red) T1 : BSP126 (or an other N-MOSFET ) JP1, JP2 : 2.54mm connectors You can add a capacitor between +12V and GND ( 100nF ) , solder it directly on JP1, below the PCB. WIRING First you have to solder on RAMPS board a 2-pin connector (+12V) and a 3-pin connector (Servo connector) as shown in the drawing. Then make a Y cable between +12V, the servo connector and JP1 on the PCB (see drawing). Be careful when you connect this cable on RAMPS board, it will make a short circuit if put in the wrong way. SOFTWARE I use this fan extender to cool down the printing head. To do this, in Marlin software, edit configuration_adv.h like this : #define EXTRUDER_0_AUTO_FAN_PIN 4 #define EXTRUDER_AUTO_FAN_TEMPERATURE 50 #define EXTRUDER_AUTO_FAN_SPEED 255 // == full speed and reprogram the firmware.