Klipper Filament Dryer

** CURRENTLY IN BETA **

Introduction

Klipper add-on to automatically turn on a filament dryer heater based on the humidity level or manually for a specified amount of time. An optional can also be opened/closed on an interval.

Sample Config

[filament_dryer filament_dryer]
interval: 1
sensor: dryer_sensor
heater: dryer_heater
target_humidity: 30
auto_target_temp: 60
manual_target_temp: 80
default_manual_dry_time: 45
auto_dry_time: 30
manual_dryer_on_macro: MANUAL_DRYER_ON_MACRO
auto_dryer_on_macro: AUTO_DRYER_ON_MACRO
dryer_off_macro: DRYER_OFF_MACRO
vent_interval: 2
vent_length: 3
vent_start_macro: OPEN_VENT
vent_end_macro: CLOSE_VENT

Requirements

• Humidity/Temperature Sensor such as BME280/680
• Heater
• Vent (optional)

Additional Config Needed

The following configs are also required for the heater and temperature sensor:

[heater_generic dryer_heater]
heater_pin: dryer:gpio6
sensor_type: temperature_combined
sensor_list: temperature_sensor dryer_sensor
maximum_deviation: 999
combination_method: min
control: watermark
max_delta: 3.0
min_temp: 0
max_temp: 100

[temperature_sensor dryer_sensor]
sensor_type: BME280
i2c_bus: i2c3_PB3_PB4
i2c_address: 119

[heater_fan dryer_fan]
pin: dryer:gpio14
max_power: 0.5
off_below: 0.31
heater: dryer_heater
heater_temp: 25
shutdown_speed: 0

The BME280 config above will depend on the MCU you're using. Please refer to the Klipper Config Reference or Klipper Discord for help on configuring this sensor.

Note that a heater_fan is added to ensure the fan turns on with the heater and turns off when the dryer chamber temp is below a certain threshold (in this case, 25 degrees). Max_power should also be adjusted to your needs. If using more than 1 fan, consider configuring these as multi_pin:

[multi_pin multi_dryer_fans]
pins: dryer:gpio14,dryer:gpio13

[heater_fan dryer_fans]
pin: multi_pin:multi_dryer_fans
max_power: 0.5
off_below: 0.31
heater: dryer_heater
heater_temp: 25
shutdown_speed: 0

Install

cd ~
git clone https://github.com/Turge08/klipper_filament_dryer
cd klipper_filament_dryer
./install.sh

Removal

cd ~
sudo rm -r ~/klipper_filament_dryer
sudo rm -r ~/klipper/klippy/extras/filament_dryer.py

Settings

• interval: How often to check the humidity level
• sensor: Sensor name of the humidity/temperature sensor
• heater: heater to control
• target_humidity: Target humidity. If humidity is above the target, the heater will be enabled. Once the humidity is below the target, the heater is turned off
• auto_target_temp: Temperature the heater will be set to when automatically enabled
• manual_target_temp: Temperature the heater will be set to when manually enabled
• default_manual_dry_time: When manually enabling the dryer, the heater will be enabled for this amount of minutes unless specified otherwise
• auto_dry_time: When automatically enabling the dryer based on the humidity, setting this value to non-zero will force the dryer to remain enabled for this amount of minutes
• manual_dryer_on_macro: name of macro to execute when heater is manually enabled
• auto_dryer_on_macro: name of macro to execute when heater is manually enabled
• dryer_off_macro: name of macro to execute when heater is disabled
• vent_interval: interval in minutes to execute the vent open macro (see vent_start_macro)
• vent_length: length of time in seconds before executing the vent close macro (see vent_end_macro)
• vent_start_macro: name of macro to execute to open the vent
• vent_end_macro: name of macro to execute to close the vent

Manual Filament Drying

The dryer can be manually enabled for the default dry time and temperature by running the following gcode command: DRY_FILAMENT To dry the filament for a custom time and temperature: DRY_FILAMENT MINUTES=120 TEMP=80

Alternatively, you can add this macro to printer.cfg to have it show up in your list of Macros in Fluidd/Mainsail:

[gcode_macro DRY_FILAMENT]
rename_existing: BASE_DRY_FILAMENT
gcode:
    {% set minutes = params.MINUTES | default(60) %}
    {% set temp = params.TEMP | default(70) %}
    BASE_DRY_FILAMENT MINUTES={minutes} TEMP={temp}

To stop the filament dryer, you can execute STOP_FILAMENT_DRYER or use the following macro:

[gcode_macro STOP_FILAMENT_DRYER]
rename_existing: BASE_STOP_FILAMENT_DRYER
gcode:
    BASE_STOP_FILAMENT_DRYER

Misc

Running the GCode command "GET_FILAMENT_DRYER_INFO" will return information about the dryer including the time remaining if the heater is enabled:

// Humidity: 26
// Temperature: 23
// Target Temp: 60
// Dry Mode: Manual
// Dry Time Left: 0:00:57

Example

My test filament dryer includes all controlled by a BTT EBB42 can bus toolhead PCB as the "dryer" mcu:

• a 24V 300W heater with a 24V fan
• a BME280 temperature and humidity sensor
• an iris vent controlled with a FS90R servo with another 24V fan

Full config:

[filament_dryer filament_dryer]
interval: 1
sensor: dryer_sensor
heater: dryer_heater 
target_humidity: 30
auto_target_temp: 60
manual_target_temp: 70
default_manual_dry_time: 120
auto_dry_time: 0
#manual_dryer_on_macro: MANUAL_DRYER_ON_MACRO
#auto_dryer_on_macro: AUTO_DRYER_ON_MACRO
#dryer_off_macro: DRYER_OFF_MACRO
vent_interval: 30
vent_length: 5
vent_start_macro: OPEN_VENT
vent_end_macro: CLOSE_VENT

[servo dryer_vent]
pin: dryer:PB9
initial_angle: 180
maximum_servo_angle: 250

[heater_fan dryer_fan]
pin: dryer:PA1
max_power: 0.5
off_below: 0.31
heater: dryer_heater
heater_temp: 25
shutdown_speed: 0

[fan_generic vent_fan]
pin: dryer:PA0
max_power: 1

[heater_generic dryer_heater]
heater_pin: dryer:PA2
sensor_type: temperature_combined
sensor_list: temperature_sensor dryer_sensor
maximum_deviation: 999
combination_method: min
control: watermark
max_delta: 3.0
min_temp: 0
max_temp: 100

[temperature_sensor dryer_sensor]
sensor_type: BME280
i2c_bus: i2c3_PB3_PB4
i2c_mcu: dryer

[gcode_macro OPEN_VENT]
gcode:
    #SET_SERVO SERVO=dryer_vent ANGLE=270
    SET_FAN_SPEED FAN=vent_fan SPEED=1
    SET_SERVO SERVO=dryer_vent ANGLE=130
    G4 P900
    SET_SERVO SERVO=dryer_vent ANGLE=180
    SET_SERVO SERVO=dryer_vent WIDTH=0

[gcode_macro CLOSE_VENT]
gcode:
    SET_SERVO SERVO=dryer_vent ANGLE=230
    G4 P900
    SET_SERVO SERVO=dryer_vent ANGLE=180
    SET_SERVO SERVO=dryer_vent WIDTH=0
    SET_FAN_SPEED FAN=vent_fan SPEED=0

[gcode_macro DRY_FILAMENT]
rename_existing: BASE_DRY_FILAMENT
gcode:
    {% set minutes = params.MINUTES | default(120) %}
    {% set temp = params.TEMP | default(70) %}
    BASE_DRY_FILAMENT MINUTES={minutes} TEMP={temp}

[gcode_macro STOP_FILAMENT_DRYER]
rename_existing: BASE_STOP_FILAMENT_DRYER
gcode:
    BASE_STOP_FILAMENT_DRYER