Keeping an eye on the conservatory’s vitals with a BME680 environmental sensor.
I bought a Bosch BME680 environmental sensor to make a mini weather station for the conservatory, this connects to a Raspberry Pi Zero via I2C with some Python to query the sensor, log the values and drive a little 128x128 mono OLED.
The BME680 measures temperature to ±1.0 °C, air pressure to ±0.6 hPa, humidity to ±0.6% relative, and air quality. The air quality calculation requires the use of a proprietary algorithm which uses these inputs in addition to a gas sensor which measures the quantity of Volatile Organic Compounds (VOCs) in the atmosphere, I am plotting the raw output of this sensor which is the resistance of a heated air sample in kΩ. High levels of VOCs result in lower values of air resistance, but the measurement is also greatly affected by the humidity.
I collected data at 10s granularity from October 2018 - October 2019 with only a couple of gaps in the data taking. These data are plotted below, now I just need to find something interesting to do with them…