2 in 1 solution for Storing and Drying Filament for 3D printing.

This repo contains all the information I gathered while developing my DryBox. It is a work in progress, and I will keep updating it as I go.

• PID control of the temperature
  • Feed forward control using the hotend temperature
    • After stabilizing the box temperature, I get .1ºC of error. I'm happy with that.
  • Anti-windup
• IO/Serial
  • Send values and readings to the serial port every X seconds
  • Receives serial commands such as:
    • SETPOINT <value> - Set the temperature setpoint
    • PID <Kp> <Ki> <Kd> <FF> - Tune the PID values
    • FAN <value> - Override the FAN speed
    • HEATER <value> - Override the Heater output
• Home assistant integration
• Silent FAN PWM control
• Safety features
  • Over temperature protection
  • DHT sensor error detection
  • Watchdog timer
• Calculates absolute humidity and the water vapor mass inside the box
• LCD 16x2 display using I2C
  • Custom icons on the LCD display
• Bowden tube from the box to the printer
• Filament runout sensor
  • Already bought, have to install

Under src/tools you can find a python script that enables realtime plotting and control of the DryBox.

Example while I was developing this

Using template sensors you can integrate via USB/Serial the DryBox with Home Assistant. (Only if your board supports Serial communication, or you can use a TTL converter too)

sensor:
  - platform: serial
    name: drybox
    serial_port: /dev/ttyACM1 # Replace with your port
    baudrate: 9600 # Replace with your baudrate
template:
  - binary_sensor:
    - name: "drybox_status"
      template: "{{ has_value('sensor.drybox') }}"
  - sensor:
      - name: "Fan Speed (PWM)"
        unit_of_measurement: "PWM"
        state: "{{ states('sensor.drybox').split(',')[0] | float(default=0) }}"
      - name: "Fan Speed"
        unit_of_measurement: "%"
        state: "{{ states('sensor.drybox').split(',')[1] | float(default=0) }}"
      - name: "Hotend temperature"
        unit_of_measurement: "ºC"
        state: "{{ states('sensor.drybox').split(',')[2] | float(default=0) }}"
      - name: "Heater setpoint"
        unit_of_measurement: "ºC"
        state: "{{ states('sensor.drybox').split(',')[3] | float(default=0) }}"
      - name: "Heater PID output"
        unit_of_measurement: "%"
        state: "{{ states('sensor.drybox').split(',')[4] | float(default=0) }}"
      - name: "Box temperature"
        unit_of_measurement: "ºC"
        state: "{{ states('sensor.drybox').split(',')[5] | float(default=0) }}"
      - name: "Box humidity"
        unit_of_measurement: "rh%"
        state: "{{ states('sensor.drybox').split(',')[6] | float(default=0) }}"
      - name: "Box absolute humidity"
        unit_of_measurement: "g/m³"
        state: "{{ states('sensor.drybox').split(',')[7] | float(default=0) }}"

Into your configuration.yaml

Some other stuff that helps:

• Hot glue gun
• IR Thermal gun
• Multimeter
• Soldering iron
• 3D printer (duh)

And some other stuff I forgot to mention here.

I printed everything with PLA, given that the temperatures should not exceed 60ºC inside the box, it should be fine. But while developing this I had an issue where the box stayed at 70ºC for a long time, and the fan support made with PLA started to deform. It still works, but probably a better idea to print in PETG or ABS ASA.

The PLA I used was HT, but I did not perform the cristalization process, so it is not as strong as it could be.

Schematic

Overview

I have a KiCad schematic for my PCB somewhere, someday I will upload it here :p

• Marlon Nardi's video DryBox project which I took heavy inspiration from
• Mighty studio's video another DryBox project which I took heavy inspiration from
• 3DMaker's Commercial DryBox
• Ricky Impley's amazing essay on Dryers
• METER Group video about absolute humidity

• Sam Knight's PWM.h
• Max Mayfield's Thermistor2. Which I can't find the original source anymore.
• Adafruit's DHT sensor library
• Max Promer's LCD Custom Character Creator which I used to create the custom icons for the LCD display