Configuring Happy Hare Firmware

After installing Happy Hare firmware, there are some configurations you need to go through before printing in multimaterial.

This page is under construction

Filament Sensors

To use the 3MS, you'll need a filament sensor. Assuming you already have one installed, you can configure it in mmu_hardware.cfg.

Locate the [mmu_sensors] section near the bottom of mmu_hardware.cfg.

Extruder/Toolhead Sensors

To configure an extruder entry sensor (a sensor right before your extruder), set your extruder_switch_pin:

Don't know your sensor pin?

If you don't know your sensor pin, and it's already configured with Klipper, locate your sensor configuration (usually filament_switch_sensor) and note the sensor_pin.

[mmu_sensors]
...
extruder_switch_pin: <SOME PIN>

To configure your toolhead sensor (a sensor right after your extruder), set your toolhead_switch_pin the same way as you set your extruder_switch_pin.

Shared Gate Sensor (Optional)

Moving backwards from the extruder, the next possible sensor you may have installed is a shared gate sensor. This goes right after the Y-splitter.

If you have a gate sensor installed, set your gate_switch_pin:

[mmu_sensors]
...
gate_switch_pin: <SOME PIN>

Pre/Post Gate Sensors (Optional)

If you have a filament sensor before or after each of your 3MS filament units, configure a pre_ or post_gate sensor.

Pre-Gate

Pre-gate sensors go before each of your filament units. Configure each of these:

[mmu_sensors]
pre_gate_switch_pin_0: <SOME PIN>
pre_gate_switch_pin_1: <SOME PIN>
pre_gate_switch_pin_2: <SOME PIN>
pre_gate_switch_pin_3: <SOME PIN>

Post-Gate

Post-gate sensors go after each of your filament units. Configure each of these:

[mmu_sensors]
...
post_gate_switch_pin_0: <SOME PIN>
post_gate_switch_pin_1: <SOME PIN>
post_gate_switch_pin_2: <SOME PIN>
post_gate_switch_pin_3: <SOME PIN>

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Existing Sensors

Before moving on, ensure all your existing filament_switch_sensor and filament_motion_sensor sections are commented out or deleted. Leaving this enabled will lead to unintended issues later on.

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Distances

There are many key distances to set up in Happy Hare firmware.

Homing Endstop

Firstly, when homing filament (checking if it is present), you have three options for the sensor to be used:

• mmu_gate Use the shared gate sensor after the Y-splitter
• mmu_gear Use the individual post-gate sensors.
• extruder Use the extruder entry sensor.

Select one of the three options in gate_homing_endstop.

Homing Distance

Next, configure the maximum distance Happy Hare should attempt to load filament to the homing sensor, before "giving up" and deciding that the spool is empty. This should usually be ~150% the distance from your filament parking position to the sensor.

Note

If you use post-gear endstops (mmu_gear), this uses the gate_preload_homing_max parameter.

This parameter is called gate_homing_max.

Parking Position

This is the location your filament should park when idle, measured from your gate endstop. This should be set to ~1-2cm above your Y-splitter.

This parameter is called gate_parking_distance.

Eject Distance

Finally, if you want to switch out which filament is in a filament unit, edit your gate_final_eject_distance. This should be the distance from your parking position to your filament unit gears, plus a small margin.

Speeds

There are many different speeds you can configure with Happy Hare firmware.

These are located in the speeds section of mmu_parameters.cfg (near the top).

Homing Speed

"Homing" is when the HH moves the filament into your extruder entry sensor to ensure they are present. You can adjust the speed at which this happens by editing the gear_homing_speed parameter.

First Load Speeds

Happy Hare allows for slowing down the initial load to deal with additional drag from the filament spool. To adjust this speed, adjust gear_from_spool_speed.

Load/Unload Speeds

To adjust your load/unload speeds during a toolchange, adjust the gear_from_buffer_speed parameter.