Two extruders one motor

Hi everyone, let me start by introducing myself, I am Pablo, I’m an electronic engineer from Argentina. I have a 3d printer that was manufactured by a local factory but they do not like people modding their product, so when I called asking on how to add a second extruder they simply said it was not possible.
So, checking my hardware, I have a smoothieboard X4, so no 2nd extruder motor channel. The solution I have found is a dual extruder based on a servo moving the motor between the two filaments (search for D.E.I.S.S. on thingiverse, I am not able to post links yet, sorry).
I have already printed everything and now I am trying to configure the smoothie. The two temperature controls work OK, I used port 2.6 with an external MOSFET to drive the second heater. The servo is a bit jumpy sometimes, and during bootup it moves, but I think it will work OK too. My main concern is with the actual motor. If I enable the code, the smoothie will not even boot. I believe this is because the firmware is not liking my dual use of the motor pins:

# Extruder module configuration
extruder.hotend.enable                          true             # Whether to activate the extruder module at all. All configuration is ignored if false
extruder.hotend.steps_per_mm                    98               # Steps per mm for extruder stepper (TOCADO)
extruder.hotend.default_feed_rate               600              # Default rate ( mm/minute ) for moves where only the extruder moves
extruder.hotend.acceleration                    50               # Acceleration for the stepper motor mm/sec² (TOCADO)
extruder.hotend.max_speed                       1000             # mm/s (TOCADO)

extruder.hotend.step_pin 2.3 # Pin for extruder step signal
extruder.hotend.dir_pin 0.22 # Pin for extruder dir signal
extruder.hotend.en_pin 0.21 # Pin for extruder enable signal

extruder offset

extruder.hotend.x_offset 0 # x offset from origin in mm
extruder.hotend.y_offset 0 # y offset from origin in mm
extruder.hotend.z_offset 0 # z offset from origin in mm

firmware retract settings when using G10/G11, these are the defaults if not defined, must be defined for each extruder if not using the defaults

extruder.hotend.retract_length 3 # retract length in mm
extruder.hotend.retract_feedrate 45 # retract feedrate in mm/sec
extruder.hotend.retract_recover_length 0 # additional length for recover
extruder.hotend.retract_recover_feedrate 8 # recover feedrate in mm/sec (should be less than retract feedrate)
extruder.hotend.retract_zlift_length 0 # zlift on retract in mm, 0 disables
extruder.hotend.retract_zlift_feedrate 6000 # zlift feedrate in mm/min (Note mm/min NOT mm/sec)

delta_current 1.30 # First extruder stepper motor current (TOCADO)

Second extruder module configuration

extruder.hotend2.enable true # Whether to activate the extruder module at all. All configuration is ignored if false
extruder.hotend2.steps_per_mm 98 # Steps per mm for extruder stepper
extruder.hotend2.default_feed_rate 600 # Default rate ( mm/minute ) for moves where only the extruder moves
extruder.hotend2.acceleration 50 # Acceleration for the stepper motor, as of 0.6, arbitrary ratio
extruder.hotend2.max_speed 1000 # mm/s

extruder.hotend2.step_pin 2.3 # Pin for extruder step signal
extruder.hotend2.dir_pin 0.22! # Pin for extruder dir signal
extruder.hotend2.en_pin 0.21 # Pin for extruder enable signal

extruder.hotend2.x_offset 0 # x offset from origin in mm
extruder.hotend2.y_offset 65.0 # y offset from origin in mm
extruder.hotend2.z_offset 0 # z offset from origin in mm

#epsilon_current 1.30 # Second extruder stepper motor current

Is this true? or I am missing something? If it is not possible to use the same pins on the two modules, how can I ‘hack’ the board into thinking it is using two modules but using the same one?

Thanks a lot for your help!!

Pablo

Imported from wikidot

Are you sure you want two extruder modules ? Smoothie isn’t design to do what you want, it doesn’t have the logic for it. I think if you want to “hack” your way around this problem, having only one extruder module ( but two temperaturecontrol modules ) is a better solution.