I have a great Rika pellet stove, but despite all the embedded electronics, it is unable to warn me just before the pellets tank is empty. As I already have my own low-power wireless devices and home automation tools, I just added a distance sensor and designed some enclosures.

What can you do on a rainy evening when you go to your hackerspace?
Take a NoteRF V2 PCB, a GPS, a battery, and you can make a LoRaWAN GPS tracker!

I am currently evaluating some solutions to build my home automation system. As a part of this system I want to monitor air quality, but, I do not have any sensor yet, so I use a public service and parse its data with Node-RED.