Title: Custom Air Quality Monitor
Date: 2025-01-13
Category: Creations
Summary: An air quality monitor made from sensor modules.
Image: airmonitor1.jpg
xTags: feed

I made custom air quality monitors to track the air in my kitchen, living room, and bedroom. They use sensor modules that detect PM2.5, PM10, CO<sub>2</sub>, VOCs, Light level, pressure, temperature and humidity. The data is sent to my [[Sensors]] database once per minute.

![[airmonitor1.jpg]]

The modules connect to an ESP8266 Arduino over I<sup>2</sup>C and UART serial. They are mounted on press-fit pegs to a 3D printed base plate I designed in FreeCAD.

The sensors used are:

- [HPMA115S0](https://www.digikey.ca/en/products/detail/honeywell-sensing-and-productivity-solutions/HPMA115S0-XXX/7202204) - Particulate Sensor
- [Adafruit SCD-30](https://www.adafruit.com/product/4867) - NDIR CO2 Temperature and Humidity Sensor
- [Adafruit BH1750](https://www.adafruit.com/product/4681) - Light Sensor
- [Adafruit SGP40](https://www.adafruit.com/product/4829) - VOC Sensor
- [Adafruit LPS22](https://www.adafruit.com/product/4633) - Pressure Sensor

The light data is used by my home automation system to know when it's night time so that motion sensors turn lights on. I also learned that the CO<sub>2</sub> level in my bedroom was doubling from 650 ppm to 1251 ppm overnight while I slept. This is bad since [high CO<sub>2</sub> concentration affects sleep](https://www.sciencedirect.com/science/article/pii/S0360132323011459), so now my automation system turns the furnace blower on while I sleep.

Before running the blower automatically (24 hour graph, CO<sub>2</sub> is the blue line):

![[airmonitor2.png]]

After:

![[airmonitor3.png]]