A Compact Air Quality Monitor You Can Wear on Your Wrist
Adafruit's Ruiz Brothers designed this compact and handy air quality monitor that can be worn on the wrist.
Air quality is important — and not just for nebulous environmental concerns. The quality of the air you breathe can have a real effect on your health, as residents of cities with heavy air pollution can attest. That might not even be something you think about if you live in a "clean" city. You can look up the air quality index (AQI) for your general area, but you'll only get metrics for the locations where public monitors exist. If you want to know the air quality where you actually are at any given time, you should check out this compact air quality monitor that can be worn on the wrist.
This device, designed by the Ruiz Brothers for Adafruit, is self-contained and quite small. It is so compact that you can, in theory, wear it on your wrist — though it is a bit too bulky for that to be comfortable for any extended period of time. You'd also have to strap the USB battery bank onto your body. More realistically, this can be carried on a belt, in a car, or temporarily placed at a job site.
It has two sensors with which to gather data on the local environment and air quality. The first is an Adafruit SCD-41, which measures CO2 levels, temperature, and humidity. The second is an Adafruit PMSA0031 air quality breakout board, which measures the actual levels of particulate matter in the air. That is an important metric and correlates with smoke, smog, and other particulates that can harm respiratory function.
To monitor those sensors, the Ruiz Brothers chose an Adafruit ESP32-S2 Reverse TFT Feather development board. Not only does that have a lot of capability, it can also take advantage of the ESP32-S2 microcontroller's various power saving modes. Its built-in TFT screen is great for showing the relevant data in glorious color. In addition, the device contains an Adafruit NeoPixel stick that lights up to give a quick visual indication of the local air quality.
Those components all tuck into a simple (but attractive) 3D-printed enclosure, complete with a wrist strap. Power comes from an Adafruit USB power bank, though any power bank or a wall wart will also work. The device's code provides a nice graphical display of the different metrics and looks great.
If you're interested in keeping tabs on the air quality in your immediate area, this is the perfect project for you.