[Yowch, this ‘blog has been dormant since 2019. Maybe it’ll go dormant again. ‘Blogging is work.] Anyway…

Contents

This is the first of several chapters.

• Part 2. The FilaBilly Dehumidifier

The Idea

I’ve got a lot of 3D printer filament. It’s stuffed into bins in the closet, some cupboards in a storage unit, some shelves, and stacks on the floor. I keep dessicant in the bins, but the filament still absorbs water.

So when I saw this article by Ben Krejci about a Peltier-based compact filament dehumidifier, I paid attention. Later, I saw the FilaBilly filament storage rack and looked into it. It uses an IKEA BILLY bookcase. Finally, I found out IKEA makes HÖGBO aluminum-framed glass doors and it all clicked.

That’s the FilaBilly Humidor¹. It’s an IKEA BILLY-based, glass doored, actively dehumidified filament storage cabinet. Then the features started creeping in.

• For performance, I’d want to seal the cabinet.
• Since I had a lot of fun adding RGB LEDs to my printer enclosure, I’d naturally want to add LEDs here.
• An air circulation fan might keep the humidity uniform through the box.
• Another humidity sensor would tell me whether the circulation fan is effective.
• A temperature/humidity display would be nice.
• It would be fun if you could turn on the lights by tapping the glass like some refrigerators.
• Shouldn’t it be tied in to Home Assistant?

As the project gets built, we’ll see which features actually get implemented. Right now it’s all just pie in the sky.

The Dehumidifier

This is the heart of it. The dehumidifier uses a Peltier thermoelectric cooling device to chill a heatsink and passes air over it. The air cools down and water vapor condenses out of it. There is a PC CPU cooler with integrated fan to move the air and cool the Peltier’s hot side. Ben found it works best when the chiller is just below freezing. Ingenious and simple, though Ben’s article makes it clear he didn’t get there in one intuitive leap.

ESPHome ties it all together. It monitors the cold side temperature and modulates the Peltier’s power using a PID loop. Basically a thermostat. It also maintains a freeze/defrost cycle to control ice buildup. It also monitors environmental temperature and humidity.

Ben’s description gave me enough information to recreate his device, but with one big problem: he designed it around a CPU cooler that is no longer available. So I’d have to redesign the housing to fit a different cooler.

Challenges

Aside from the CPU cooler, there are other open questions about whether the FilaBilly Humidor is feasible.

• Can I seal a BILLY well enough to keep the air inside dry?
• How do I pass power for the dehumidifier and lights?
• How do I mount the lights?
• What do I do with the extracted water?
• Peltiers are inefficient. How much electricity will this use?
• How dry will this actually be?

Those questions are still open, though I have plans to address them.

Progress

I’ve redesigned the dehumidifier housing to fit a Noctua NH-U9S. I’ve built it. It works. Part Two of this series will go into detail about the dehumidifier.

I’ve acquired a BILLY and I’ve attempted to seal it with polyurethane. I’ve also got some LED strips and aluminum channels for them. I’ve done some research on weather stripping. I’ve printed the FilaBilly brackets and bought steel conduit for the filament rails. And I have another Noctua fan for air circulation.

Wish me luck!

Project Resources

My work on this project is scattered around the web.

This Github repository has all the digital artifacts: CAD files, ECAD files, firmware, and an assembly manual I’m proud of.

The Dehumidifier print files are published on Printables.

I have a build thread on Mastodon which I update regularly. Be warned that it’s long and it rambles. Still, if you want to track the project progress, follow #FilaBillyHumidor there.

And watch this space. Maybe I’ll publish another post in less than six years.