The air sensor connects via USB to a computer. For indoor use, hooking the sensor up to any computer would be good enough for spot readings, but our plan was to put the computers outside. We decided to use a tiny and very cheap computer called the Raspberry Pi Zero W.
Raspberry Pis are bare-bones computers that cost between $10 and $50, but do not include screens, storage, or any peripherals—not even an electrical cable to power them with. They do, however, run a full operating system, which makes them quite easy to use compared to the alternatives we considered for this device (notably Arduino).
We settled on the second-cheapest Raspberry Pi because we have very simple computing requirements. Though the Pi Zero W is very slow compared to any other modern computer, it is certainly capable of doing the computations we need. We did not use the cheapest Raspberry Pi, the Pi Zero (without a W), because we wanted our computers to be able to report wirelessly.
We were forced to purchase the Pi Zero Ws in kits, which included a case, a power supply, and a MicroSD card, because the computers alone are rationed out at one per customer. Unfortunately, this drove the price of each Pi up from an advertised price of $13 to $65 (CAD, including tax and shipping).
The Pi Zero W (which I’m going to call “the Pi” from now on) runs Raspbian, a free operating system, which can be installed using a utility called NOOBS. Raspbian comes with the free programming language Python preinstalled. We used Python to collect and manipulate the measurements from the SDS011 air-quality sensor.
Setting up the Pi is fairly straightforward if you have the cables and peripherals—but to do it over a graphical interface, you’ll need quite a few of those, including:
- A MicroSD card writer
- A USB hub
- And a USB keyboard and mouse
- A mini-HDMI to HDMI adapter
- An HDMI cable
- A USB OTG cable
- A somewhat beefy USB power adapter
In addition, you’ll need a MicroSD card. These peripherals add considerably to the cost of the $13 Raspberry Pi if you don’t have them in a drawer somewhere.
There is excellent help available on the internet, particularly Reddit, to get you to the point where you can boot the operating system.