Air Quality, Your Way

If you are an electronics hobbyist and you have never built an environmental monitor, there is no time like the present. Building such a device is a common rite of passage for new makers, but even if you have some experience under your belt, engineer Randy Durrant’s take on this classic project has got some things to keep you interested too. It is simple enough for a beginner to build, yet it is loaded with features and ripe for expansion, which is enough to hold the attention of a seasoned hobbyist.

Durrant designed a custom, 3D-printed enclosure to house all of the device’s hardware. That hardware includes an Adafruit Feather M0 Express (other Feather boards should also work) to serve as the main processing unit, and a Novaduino 2.4-inch color LCD display. A rotary encoder and set of three tactile buttons are included in the build to handle user inputs.

As designed, the monitor comes equipped with a BME280 sensor to measure temperature, humidity and barometric pressure, as well as a ENS160 sensor that measures a variety of factors relevant to air quality. You are not limited by these sensors, of course — you can install anything you like to make the environmental monitor your own.

Out of the box, the system provides a fairly comprehensive look at your immediate surroundings. The ENS160 keeps an eye on total volatile organic compounds, estimated CO₂, and various gases such as ethanol, toluene, and hydrogen, combining those readings into an Air Quality Index. Meanwhile, the BME280 tracks environmental essentials like temperature, humidity, and pressure. All of this data is displayed instantly on the Novaduino touchscreen, offering a polished user interface driven by entirely open source software.

Because sensors generate heat and can influence one another, the BME280 is thermally isolated inside a dedicated enclosure and separated from the ENS160. Early prototypes revealed temperature drift when the sensors were adjacent, leading to enclosure refinements and the addition of software calibration variables. Users can further fine-tune temperature, humidity, and pressure offsets.

A small but important configuration step involves setting your altitude in the software so the device can calculate sea-level equivalent barometric pressure. This is a one-time adjustment, though future software updates may allow editing the value directly through the rotary encoder.

With its flexibility, transparency, and expandability, Durrant’s environmental monitor is more than a weekend project — it is a platform for experimentation, learning, and customization. Read up on all the details to get started on your own environmental monitor today.