Hi ! Inspired by RichRap Filament Box and the pretty nice filament monitor from Enrico Miglino I want to build a filament box that:

• is air tight.
• can be heated.
• have an humidity and temperature measure.
• measure the amount of filament remaining using a weight scale.
• can be controlled/notifies via the network or lcd/keyboard.
• spools can be easily changed and secured.

Sources:

• https://create.arduino.cc/projecthub/balearicdynamics/3d-printer-filament-monitor-for-arduino-a158a9
• https://www.element14.com/community/community/arduino/arduino-projects/blog/2017/06/24/3d-printer-filament-monitor-with-arduino
• http://richrap.blogspot.lu/2018/02/diy-heated-drybox-for-3d-printing.html

Components (incomplete):

• Controller: STM32 Nucleo Board (it can be a Arduino)
• AC/DC Relay Board to control the heat pad
• 14W 28*28cm 220V Amphibian Pet Heat Pad
• I2C OLED Display
• DHT22 Sensor
• Ethernet Shield, I have an ENC28J60
• Digital Loading Cell of 20Kg with HX711
• Keyboard (optional)
• Small PSU and few other stuff (not complete yet)
• 608ZZ Roller Bearings (by 8)
• M8 Screws/Nuts
• M6 Screws/Nuts

Design

I want to be able to put two spools inside the box. I do not have any big constraint on the volume it can be up to 600mm by 600mm, with a constrained width of 200mm. For the moment I want to put spools up to 1Kg OD 240mm, Width 100mm. I want to design a very compact base to not 3d print too much and iterate quickly on the design.

My design box looks like the following.

The heated element is vertical, I can put another one if needed. There is enough room to put all the electronic "inside" the box, there is enough height and room next to filament support/weight system.
So far, I do not have the load cell so I can just "improvise". The top base has different slots to allow to adjust the bearing supports in one way, while the bearing support should have (not already done) slots in the other way to allow to adjust in both directions. There is just a block at the base to screw on the load cell, the load cell is in magenta and there is the second part of the base supporting the other part. There are 4 bearing supports for each spool (in green).

I had a look to support bigger spool of 2Kg, the base should be at least 150mm wide and 200mm long, the majority of spools are having OD 300mm, Width up to 120mm. I will see later when the "small" box will be implemented and running. Bigger spools come with another set of potential problems.