As part of my Hypercube Evolution 3D Printer build I had to re-assign the E1 stepper as the second Z motor and the E1 heater cartridge output as the part cooling fan. Here is how I did it!
Re-assigning the E1 stepper output
After downloading the Marlin firmware from github (here) and you open the “Marlin.INO”file in the Arduino IDE. Navigate to the Configuration_adv.H file and look for the below lines. By default the “define Z_DUAL_STEPPER_DRIVERS” line has a // in front of it. All you need to do is remove these 2 forward slashes. That’s it!
// A single Z stepper driver is usually used to drive 2 stepper motors.
// Uncomment this option to use a separate stepper driver for each Z axis motor.
// The next unused E driver will be assigned to the second Z stepper.
#define EXTRUDERS 1
Re-assigning the E1 heater output
After downloading the Marlin firmware from github (here) and you open the “Marlin.INO” file in the Arduino IDE. Navigate to the Configuration_adv.H file and look for the below lines. All you need to change “define E0_AUTO_FAN_PIN -1” to “define E0_AUTO_FAN_PIN 7” you can also adjust the automatic fan switch on set point by changing the number on the line “define EXTRUDER_AUTO_FAN_TEMPERATURE 50”. Remember though these temperatures are in Celsius!
// @section extruder
Extruder cooling fans
Extruder auto fans automatically turn on when their extruders'
temperatures go above EXTRUDER_AUTO_FAN_TEMPERATURE.
Your board's pins file specifies the recommended pins. Override those here
or set to -1 to disable completely.
Multiple extruders can be assigned to the same pin in which case
the fan will turn on when any selected extruder is above the threshold.
define E0_AUTO_FAN_PIN 7
define E1_AUTO_FAN_PIN -1
define E2_AUTO_FAN_PIN -1
define E3_AUTO_FAN_PIN -1
define E4_AUTO_FAN_PIN -1
define CHAMBER_AUTO_FAN_PIN -1
define EXTRUDER_AUTO_FAN_TEMPERATURE 50
define EXTRUDER_AUTO_FAN_SPEED 255 // == full speed