Dev tools · alternatives · 2026
24 alternatives to I built an under-the-door fan duct to lower bedroom CO2
Hi HN, This is my attempt to fix groggy mornings by lowering my bedroom CO2 from 1700 ppm to ~900 ppm. I designed a simple, 3D-printed fan duct that directs air under the door to improve air circulation. A note on the design process: I used CadQuery, a Python library for creating parametric 3D models. I didn't know tools like this existed and highly recommend it if you can program; it turned out to be more convenient than manually iterating on prototypes in a GUI. The project is open source and the post explains the full build. Happy to answer any questions.
This is an open-source 3D-printed fan duct designed to improve bedroom air circulation by directing airflow under doors, reducing CO2 levels from around 1700 ppm to 900 ppm to address grogginess. The maker used… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes.
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Hey HN! Some more info: I’m an NHS doctor and the founder of Pi-A (https://www.pi-a.io) which developed Lungy (https://www.lungy.app). Lungy is an app (iOS only for now) that responds to breathing in real-time and was designed to make breathing exercises more engaging and beneficial to do. It hopefully has many aspects of interest to the HN community – real-time fluid, cloth and soft body sims running on the phone’s GPU. My background is as a junior surgical trainee and I started building Lungy in 2020 during the first COVID lockdown in London. During COVID, there were…
2023 · lungy.app · its alternatives →
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2024 · hajo.me · its alternatives →
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Here's a "behind-the-scenes" look at my development of a cool sensor during my PhD (electrical engineering). This sensor is only about 1/3 of my total research for my degree and took about a year. I've been on HN for a while now and I've seen my fair share of posts about the woes of pursuing a PhD. Now that I'm done with mine I wanna share some anecdotal evidence that doing a PhD can actually be enjoyable (not necessarily easy) and also be doable in 3 years. When I started I knew I didn't want to work on something that would never leave the lab or languish in a dissertation PDF no one…
2024 · paulbupejr.com · its alternatives →
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In the cold season we tend to keep the windows closed. The air gets "stale": humidity often rises above 60 %, which can harm our wellbeing and promote mould. At the same time the CO₂ level in the air increases, which impacts our ability to concentrate. So I built a room air monitor that stays unobtrusive as long as everything is in the green zone, but becomes deliberately noticeable once thresholds are exceeded. For my personal love of statistics I also visualise the measurements in a clear dashboard.
Nov 2025 · nicolin-dora.ch · its alternatives →
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3D printing is such a fascinating field of technology, so a couple months ago, I decided to take a deep dive and learn how they actually work! This took me to one of my very first PCB projects, a small, cheap, 3D printer motherboard. While it's not the most cutting edge board, I learned a lot and I fully documented my process designing it (https://github.com/KaiPereira/Cheetah-MX4-Mini/blob/master/J...), so other people can learn from my mistakes! It runs off of an STM32H743 MCU, has 4 TMC stepsticks with UART/SPI configurations,…
Dec 2025 · github.com · its alternatives →
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Hey HN! I’m an NHS doctor and the founder of Pia (https://www.piahealth.co) which developed Lungy (https://www.lungy.app). Lungy is an iOS app that responds to breathing in real-time and was designed to make breathing exercises more engaging and beneficial to do. It’s been two years since Lungy launched (here’s the original ShowHN: https://news.ycombinator.com/item?id=34534615) and it's had a huge update and complete redesign. We rebuilt the whole app, and added a real-time 3D soft body solver which gives some really cool interactions like blobs /…
2025 · apps.apple.com · its alternatives →
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A simple webserver / CO2 Monitor. Contribute to Maddimax/MadCO2 development by creating an account on GitHub.
2019 · github.com · its alternatives →
- 8FP
Hello HN users, This is a CAD by code project I have been working on on my free time for more than year now. I built it with 3 goals in mind: - It should be familiar to CAD designers who have used other programs. Same workflow, same terminology. - Reduce the mental effort required to create models as much as possible. This is achieved by: - Provide live rendering and visual guidance as you type. - Allow the user to reference existing edges/faces on the scene instead of having to calculate everything. - Provide interactive mouse helpers for features that are hard to write by code: Only 3…
Apr 2026 · fluidcad.io · its alternatives →
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An air purification system designed as a headboard
2022 · kickstarter.com · its alternatives →
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Quilt▲107The smartest and most efficient heat pump on the market
Feb 2026 · quilt.com · its alternatives →
- 11IM
Hello everyone, My son loves Hacker News, so I am using his account. I love innovation and technology. With the restrictions due to Coronavirus from practicing in my clinic. I created a system that replaces the air in my office in 20 seconds. Those vacuums are also filled with UV-rods inside to kill any viruses. The air is release below the office in a 2-3 foot basement, which is also filled with UV rods. https://youtu.be/UfYt1w156QA https://youtu.be/UpO8WXOlgcQ (side-by-side) Given how much my son enjoys Hacker News I thought you would all enjoy it. Here are…
2020 · its alternatives →
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Squair▲162I built Squair because my phone was giving me anxiety - and it was also the only thing in my pocket when anxiety hit. The problem: 4 cups of coffee just to focus. Then the anxiety kicks in. Chest tight. Racing thoughts. Scrolling reels to "calm down" made it worse. I Googled "anxiety relief" at 2am and found box breathing — same technique Navy SEALs use in combat. First time I tried it, I felt the difference within 2 minutes. No crash. No pills. Just breathing. So I built an app around it. 6 months. Solo dev with a full-time job. 112 builds. 2 App Store rejections. Finally live. What it…
Jan 2026 · squair.app · its alternatives →
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Hi everyone started this project a year ago to generate the CAD for a Jet Engine Axial Compressor. I am now open sourcing this tool that can take in a JSON file with specs and generate the CAD assembly. Still has a lot of work to improve designs but there isn't anything the Open Source community can't accomplish!
2023 · github.com · its alternatives →
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Climeworks permanently removes carbon dioxide from the air.
2020 · climeworks.com · its alternatives →
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Ventorah▲90run virtual wind tunnel aerodynamic analysis in your browser
Jul 2026 · ventorah.com · its alternatives →
- 16MD
2020 · dropbox.com · its alternatives →
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Having a problem-solving mindset is incredibly valuable and rewarding, especially when it leads to exciting DIY adventures. My latest experience with a noisy GPU fan turned into just such an opportunity. It guided me through fascinating explorations involving ATX power, MOSFET motor drivers, Pulse W
2025 · shafq.at · its alternatives →
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Fidget Moire▲783-in-1 air freshener with dynamic animation
2021 · numberzero.net · its alternatives →
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Small Form Factor printable case for AMD Raven Ridge systems - phkahler/mellori_ITX
2022 · github.com · its alternatives →
- 21AI
(space = reset) Fluid mechanics is an extremely interesting topic and I have been creative coding for a couple of months now. Therefore I started working on flow fields in processing. It had so much fun playing around with the different parameters in this project, I decided to rewrite in p5.js an added a control panel. You can change most of the parameters (within some constraints I thought to be reasonable), randomize the values and export and import settings. Hopefully some coders here get inspired and also join the great creative coding community.
2024 · synapse.nugatio.com · its alternatives →
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A modern and modular Figma design system for any type of app
2022 · build.airdev.co · its alternatives →
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BedJet 3▲91Sleep inducing climate control just for your bed 🛌❄️
2018 · kickstarter.com · its alternatives →
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Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →