It's hard to see what's in the air around us—unless you've got a handy portable air quality monitor like Arnov Sharma. This maker uses our favorite microcontroller, the Raspberry Pi Pico 2, to power his custom handheld, making it possible to see what exactly you're breathing in and how much of it is around. This portable air quality meter is an open-source project with full build details available at Hackster.
Sharma says the meter is built around an MQ135 air quality sensor. This module works with various controllers and can operate efficiently using a Pico 2. The Pico is also connected to an OLED display to get visual output. This screen has a custom interface that displays specific particle levels in real time.
One important thing to note about this portable air quality monitor is the limitation of the sensor. It doesn't provide the full scope of particle assessment you would find with a complete Air Quality Index (AQI). Sharma confirms that his handheld can detect only CO2, smoke particles, benzene, alcohol, ammonia, and nitrogen oxide.
The project's first iteration was built using a Raspberry Pi Pico 2, but it was eventually swapped out for a Firebeetle 2 ESP32-E. This was mainly because the Pico had no battery charging circuit, requiring more space for a second module. The Firebeetle has an integrated TP4056, which was a little more practical for the unit.
If you want to recreate this project, you can use either board as the microcontroller if you're mindful of how you plan to recharge the battery. It will need to be connected to the MQ135 air quality sensor, the SSD1306 screen, and the 14500 Lithium Ion battery. The housing is 3D printed, as well. You can also explore the source code for the project over at the project page on Hackster.
If you want to examine this Raspberry Pi project in greater depth, you can check out the complete build guide at Hackster. You can also follow Arnov Sharma for more cool Raspberry Pi projects.
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Ash Hill is a contributing writer for Tom's Hardware with a wealth of experience in the hobby electronics, 3D printing and PCs. She manages the Pi projects of the month and much of our daily Raspberry Pi reporting while also finding the best coupons and deals on all tech.
Lower-end air quality monitors are notorious for being inaccurate. I'd love to hear from a user who bought two of these and gets the same readings on both given the same air.
