air quality

38 Articles

AqMood Is An Air Quality Monitor With An Attitude

March 27, 2025 by No comments

You take your air quality seriously, so shouldn’t your monitoring hardware? If you’re breathing in nasty VOCs or dust, surely a little blinking LED isn’t enough to express your displeasure with the current situation. Luckily, [Tobias Stanzel] has created the AqMood to provide us with some much-needed anthropomorphic environmental data collection.

To be fair, the AqMood still does have its fair share of LEDs. In fact, one might even say it has several device’s worth of  them — the thirteen addressable LEDs that are run along the inside of the 3D printed diffuser will definitely get your attention. They’re sectioned off in such a way that each segment of the diffuser can indicate a different condition for detected levels of particulates, VOCs, and CO2.

But what really makes this project stand out is the 1.8 inch LCD mounted under the LEDs. This display is used to show various emojis that correspond with the current conditions. Hopefully you’ll see a trio of smiley faces, but if you notice a bit of side-eye, it might be time to crack a window. If you’d like a bit more granular data its possible to switch this display over to a slightly more scientific mode of operation with bar graphs and exact figures…but where’s the fun in that?

[Tobias] has not only shared all the files that are necessary to build your own AqMood, he’s done a fantastic job of documenting each step of the build process. There’s even screenshots to help guide you along when it’s time to flash the firmware to the XIAO Seeed ESP32-S3 at the heart of the AqMood.

If you prefer your air quality monitoring devices be a little less ostentatious, IKEA offers up a few hackable models that might be more your speed.

Cute Face Tells You How Bad The Air Quality Is

February 13, 2025 by 3 Comments

You can use all kinds of numbers and rating systems to determine whether the air quality in a given room is good, bad, or somewhere in between. Or, like [Makestreme], you could go for a more human visual interface. He’s built a air quality monitor that conveys its information via facial expressions on a small screen.

Named Gus, the monitor is based around a Xiao ESP32-C3. It’s hooked up with the SeeedStudio Grove air quality sensor, which can pick up everything from carbon monoxide to a range of vaguely toxic and volatile gases. There’s also a THT22 sensor for measuring temperature and humidity. It’s all wrapped up in a cute 3D-printed robot housing that [Makestreme] created in Fusion 360. A small OLED display serves as Gus’s face.

The indications of poor air quality are simple and intuitive. As “Gus” detects poor air, his eyelids droop and he begins to look more gloomy. Of course, that doesn’t necessarily tell you what you should do to fix the air quality. If your issue is pollution from outside, you’ll probably want to shut windows or turn on an air purifier. On the other hand, if your issue is excess CO2, you’ll want to open a window and let fresh air in. It’s a limitation of this project that it can’t really detect particulates or CO2, but instead is limited to CO and volatiles instead. Still, it’s something that could be worked around with richer sensors a more expressive face. Some will simply prefer hard numbers, though, whatever the case. To that end, you can tap Gus’s head to get more direct information from what the sensors are seeing.

We’ve seen some other great air quality projects before, too, with remarkably similar ideas behind them. Video after the break.

Continue reading “Cute Face Tells You How Bad The Air Quality Is” →

Upper Room UV-C Keeps Air Cleaner

December 18, 2024 by 59 Comments

2020 saw the world rocked by widespread turmoil, as a virulent new pathogen started claiming lives around the globe. The COVID-19 pandemic saw a rush on masks, air filtration systems, and hand sanitizer, as terrified populations sought to stave off the deadly virus by any means possible.

Despite the fresh attention given to indoor air quality and airborne disease transmission, there remains one technology that was largely overlooked. It’s the concept of upper-room UV sterilization—a remarkably simple way of tackling biological nastiness in the air.

Continue reading “Upper Room UV-C Keeps Air Cleaner” →

A CO2 Traffic Light On An SAO

November 6, 2024 by 12 Comments

[David Bryant] clearly has an awareness of the impact of an excess concentration of CO2 in the local environment and has designed an SAO board to add a CO2 traffic light indicator to one of the spare slots on the official Hackaday Supercon 2024 badge.

The part used is the Sensirion SCD40 ‘true’ CO2 sensor, sitting atop an Adafruit rider board. [David] got a leg up on development by creating a simple SAO breakout board, which could have either the male and female connectors fitted, as required. Next, he successfully guessed that the badge would be based around the RP2040 running MicroPython and hooked up an Adafruit Feather RP2040 board to get started on some software to drive the thing. This made hooking up to the official badge an easy job. Since the SAO has only two GPIOs, [David] needed to decode these to drive the three LEDs. There are a few ways to avoid this, but he wanted to relive his earlier EE college years and do it the direct way using a pair of 74HC00 quad NAND gate chips.

We’ve seen a few CO2 monitors over the years. This sleek little unit is based around the Seeeduino XIAO module and uses an LED ring as an indicator. Proper CO2 monitors can be a little pricey, and there are fakes out there. Finally, CO2 is not the only household pollutant; check out this project.

Pac-Man Ghost Helps With Air Quality Sensing

October 21, 2024 by 13 Comments

In the past, building construction methods generally didn’t worry much about air quality. There were enough gaps around windows, doors, siding, and flooring that a house could naturally “breathe” and do a decent enough job of making sure the occupants didn’t suffocate. Modern buildings, on the other hand, are extremely concerned with efficiency and go to great lengths to ensure that no air leaks in or out. This can be a problem for occupants though and generally requires some sort of mechanical ventilation, but to be on the safe side and keep an eye on it a CO2 sensor like this unique Pac-Man-inspired monitor can be helpful.

Although there are some ways to approximate indoor air quality with inexpensive sensors, [Tobias] decided on a dedicated CO2 sensor for accuracy and effectiveness, despite its relatively large cost of around $30. An ESP32 handles the data from the sensor and then outputs the results to an array of LEDs hidden inside a ghost modeled after the ones from the classic arcade game Pac-Man. There are 17 WS2812B LEDs in total installed on a custom PCB, with everything held together in the custom 3D printed ghost-shaped case. The LEDs change from green to red as the air quality gets worse, although a few preserve the ghost’s white eyes even as the colors change.

For anyone looking to recreate this project and keep an eye on their own air quality, [Tobias] has made everything from the code, the PCB, and the 3D printer files open source, and has used accessible hardware in the build as well. Although the CO2 sensors can indeed be pricey, there are a few less expensive ways of keeping an eye on indoor air quality. Some of these methods attempt to approximate CO2 levels indirectly, but current consensus is that there’s no real substitute for taking this measurement directly if that’s the metric targeted for your own air quality.

The sensor hub in all its glory, sensor itself on top, standing on 3D-printed feet, and the PCB on the bottom

Hacker-Friendly And Elegant Air Quality Sensor Hub

February 27, 2023 by 9 Comments

Ever wanted an indoor environment sensor that’s dead simple yet a complete package? That’s the anotter-sensor-hub project from [Jana Marie], designed for the Sensirion SEN05x series sensors, with a SEN055 sensor shown in the picture above. Given such a sensor, you can measure VOCs and NOCs (Volatile and Non-Volatile Organic Compounds), as well as PM1, PM2.5, PM4 and PM10 particulate matter indices, with temperature and humidity sensing thrown in for good measure. Fully open and coupled with 3D printable stand files, this alone makes for an air quality hub fit for a hacker’s desk. That’s not all, however — this board’s elegant extensibility is a good match for the sensor’s impressive capabilities!

The PCB itself might look simple, it’s simply an ESP32 and some supporting circuitry required. But you’ll notice there’s also a trove of connector footprints for different interfaces; whatever else you might want to add to your sensor hub, whether it connects through I2C, SPI or PWM, you can! As usual, the sensor itself is the most expensive part of such a project — the boards themselves are around $5 USD apiece fully assembled, but one sensor-included hub will set you back roughly $42 USD. That said, it’s a great value for the price, and the trove of sensing data you can get might just more than pay for itself in quality-of-life improvements you make. Of course, everything is open-source and comes as a complete packages for you to start using. The firmware, KiCad files, 3D holder and even Grafana dashboard files can be found on GitHub.

Such air quality sensor platforms have been getting more and more popular, and hackers have been paying attention. Having a full open-source package like this at our disposal is amazing. If you’re looking for a cheaper “baby’s first air quality sensor”, drop by your local IKEA — there’s a way less featureful but quite cheap sensor that you can equip with an ESP8266, perhaps, even on a custom PCB.

Better Air Quality Sensing With CO2

November 21, 2022 by 19 Comments

Measuring air quality, as anyone who has tried to tackle this problem can attest, is not as straightforward as it might seem. Even once the nebulous term “quality” is defined, most sensors use something as a proxy for overall air health. One common method is to use volatile organic compounds (VOCs) as this proxy but as [Larry Bank] found out, using these inside a home with a functional kitchen leads to a lot of inaccurate readings. In the search for a more reliable sensor, he built this project which uses CO2 to help gauge air quality.

Most of the reason that CO2 sensors aren’t used as air quality sensors is cost. They are much more expensive than VOC sensors, but [Larry] recently found one that was more affordable and decided to build this project around it. The prototype used an Arduino communicating over I2C to the sensor and an OLED screen, which he eventually put in a 3D printed case to carry around to sample CO2 concentration in various real-world locations. The final project uses a clever way of interfacing with the e-paper display that we featured earlier.

While CO2 concentration doesn’t tell the full story of air quality in a specific place, it does play a major role. [Larry] found concentrations as high as 3000 ppm in his home, which can cause a drop in cognitive function. He’s made some lifestyle changes as a result which he reports has had a beneficial impact. For human-occupied indoor spaces, CO2 can easily be the main contributor to poor air quality, and we’ve seen at least one other project to address this concern directly.