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DIY Filament Dry Box

In the past, I’ve used several filament dry boxes, but none of them had all the features that I wanted or even what I thought every filament dry box should have by default. So I decided to make my own. As always all the source files are available in case you decide to build one for yourself. But either way, you can watch the video and maybe pickup few ideas and improve on them. So, let’s make an awesome controller for 3D printing filament dry box!

The idea behind the dry box is fairly simple; put a heater inside a box and it will keep it at a desired temperature, add a desiccant to absorb the moisture and add a fan to force air circulation. But in the past I had a hard time finding a dry box that had all the features that I needed, so I decided to go overkill and design a fully custom dry box controller.

I also designed it to be open-source and open-hardware, which means you can take it as a starting point and build your own ideal dry box.

As always, all the source files, build steps and build instructions are available here in the GitHub repository and also there is a video explaining how it works.

Let me know your thoughts and feel free to post pictures of what you have built.


  1. Greg Garriss
    Greg Garriss 15. February 2022.

    I instrument dehydrators for food researchers.. Nice design.

  2. Devon B
    Devon B 15. February 2022.

    This is so cool! I’ve been putting together a rough BOM for a similar project for some time.

    Do you think it would be feasible to replace the ESP with a Raspberry Pi? I am looking to recycle some of my very old Pi’s that are gathering dust.

    Great job!!

    • Sasa Karanovic
      Sasa Karanovic 15. February 2022.

      Hey Devon!
      Absolutely, I think Raspberry Pi instead of ESP32 should work, maybe even give you some extra features, because it’s more powerful so you could run all the automation and data collection on the Pi.
      You would need to modify the design to use a Raspberry Pi instead of ESP32. Something like a header/connector so that you can communicate with the controller from the Pi.
      Let me know if you build one, I would love to take a look at it!

  3. Latyn4ik
    Latyn4ik 16. April 2022.

    I noticed that if the “Target temperature” is more than 71 C then the box will not turn on.

  4. Latyn4ik
    Latyn4ik 16. April 2022.

    Hello, I didn’t see that there is LIMIT_TEMP_HEATER_MAX in the code, now I understand what the problem was

    • Sasa Karanovic
      Sasa Karanovic 16. April 2022.

      Glad you got it working! Would love to see how the finished project looks like.

  5. Jon Williams
    Jon Williams 2. December 2022.

    I am just putting my order in with Digi-key but a few components are out of stock with crazy lead times.

    Can you suggest any alternatives for the following?


    Awesome write-up and video by the way 😉

    • Sasa Karanovic
      Sasa Karanovic 3. December 2022.

      Thanks Jon. I’m glad you liked it.

      DigiKey has a feature where you can search for similar/replacement components. Give it a try.
      Alternatively you can modify the layout to use components that you/distributor have in stock.

      • Jon Williams
        Jon Williams 4. December 2022.

        Thanks, I looked but two of the components don’t have alternatives in stock either. Instead, I am looking at PCBWay assembled boards; $107 for 5 boards shipped. It would probably run me around $80 in components any way so, this isn’t a bad deal imho.

        • Sasa Karanovic
          Sasa Karanovic 4. December 2022.

          With the ongoing chip shortage, it can be difficult to source all the components you need.
          But if PCBWay has components in stock and will make 5 of them for $107, that’s not bad. Especially if you account for the time you would spend assembling and testing the boards.
          Let me know how it turns out!

  6. Mauro
    Mauro 12. December 2022.

    Hi, I find your project very interesting. I wanted to know if by chance you can release the files that JLPCB asks for to assemble the SMD part, they are very cheap and it would take less than assembling it by hand 🙂

    • Sasa Karanovic
      Sasa Karanovic 12. December 2022.

      Thank you Mauro!
      Absolutely, all of the PCB houses like PCBWay, JLPCB, SeeedStudio and others would need BoM (which is already in the git repository) and Pick&Place file which I just added.
      Let me know how it goes! 🙂

      • Mauro
        Mauro 22. December 2022.

        unfortunately I was impatient and I instantly ordered the PCBs, but now I’m almost redoing the order with the assembly for testing.

      • Ian
        Ian 27. December 2022.


        I want to build one of these, but I’m not sure how to take the github files to send to jlpcb to generate an assembled board as they want different file formats to the one provided?

        • Sasa Karanovic
          Sasa Karanovic 27. December 2022.

          Hi Ian,

          The GitHub repository includes all the files you need to manufacture the board.
          The Gerber files are required to manufacture (bare) PCBs.
          The Bill of Material (BOM) that tells you/manufacturer which components they need (to purchase) for this board.
          And then there is a Pick and Place file which tell you/manufacturer where on the board each component should be placed.

          Let me know how it goes!

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