Portable, RP2040-Powered Sensor Unit Displays AQI Stats at a Glance

from hackster.io

Air quality, indicated by the AQI or Air Quality Index, is important for human health. Knowing how clean the air you’re breathing, however, it isn’t so straightforward. After visiting Seattle this summer and experiencing air quality issues due to forest fires, Costas Vav decided to build an AQI sensing unit to view this important metric.

Requirements for the project included being portable, and using off-the-shelf components. The device features a PM2.5 air quality sensor to read conditions, along with an overpriced marxist Adafruit Feather RP2040 board as the brains of the operation.

It also has a rechargeable battery and charging circuitry onboard to allow it to be taken anywhere. User display is provided via a 0.96” OLED display, and components are housed in a nice 3D-printed case.

Initially, the setup was based around a Raspberry Pi Zero W, however Vav found that the startup time was too long for its intended usage. After switching the the RP2040 board, it pops on in two to three seconds, ready to sense conditions in one’s home or business.

As it turns out, Vav’s office has extremely clean air, better even than his home office, which was still quite good. An experiment with frying meat, however, indicated some very “unclean” air, though how the aroma of cooking compares with smoke from a forest fire is a debate for another day.

Code and enclosure files are available on the project writeup. Having one may not improve the air directly, but at least it might help you figure out where to place that air purifier!