How does this work?

• Regular readings are taken from my flat with an SDC40 CO2 Monitor mounted on an ESP32 microcontroller.
• Data is ingested by InfluxDB, a time series database running on a linux server (aka an old PC in the corner of my room).
• This node.js script is run server-side to query InfluxDB and write data to a json file.
• Promises are used to ensure all aynchronous queries are resolved before the file is written out.
• A scheduled shell script runs this script, commits and pushes the updated readings file to the GitHub Pages repository for this site
• This would not be needed if the server was exposed to the internet. I do not want to expose the server to the internet.
• The Fetch API is used in a client-side script to access the readings file and export a promise which resolves to a javascript object containing the readings data. Scripts in the html body import this to...
  • Set the gauge values.
  • Assign values to html elements.
  
  Credit:
  • Hosted on GitHub Pages
  • Gauges are made using gauge.js
  • Microcontroller code can be found in this repo.
  • Anything else is my fault.