The Room Environment Monitor (REM) project was something that I started back in 2017. I wanted a small IoT device that could tell me if there was a concerning amount of volatile organic compounds (VOCs) and CO2 in my workshop. I built the first version based on a Raspberry Pi Zero, CCS811 air quality monitor, and a BME280 humidity and temperature sensor.
I went through multiple iterations of the project with the overall objective to reduce cost while increasing the precision of the measurements being made. At that time, the CCS811 sensor cost about 40 dollars alone, which brought the V1 bill of materials (BOM) cost to about 70 CAD. Fast forward to 2023, Ikea released their Vindriktning air quality monitor which uses a PM1006K sensor to measure 2.5um matter in the air. I designed my latest version of the Room Environment Monitor to replace the controller inside and make use of the device's case.
The REM collects data from the following sensors:
- BME280 - Temperature, Humidity, Pressure
- SGP40-2.5k - VOCs, C02
- PM1006K - particulate matter in the air (2.5ug/m^3, 1.0ug/m^3, 10ug/m^3)
This data is then pushed to a MQTT broker via the MQTT networking protocal. The broker then broadcasts the data to any subscribers. I use n8n which is a workflow automation tool to subscribe to the REM data stream. n8n ensures that each piece of data in this stream is inserted as a new row in to a Postgres database. Bellow is a sequence diagram that shows how the data flows and is collected.
I use Grafana, a free an open source tool to visualize the collected data in my Postgres database. Here is a screenshot of the dashboard that I have created to visualize the data.
