Monitor level of LPG/Propane gas bottles?

Hardware Home Automation
1

I got some gas bottle installed over the weekend for hot water heating…

The tinkerer in me immediately started wondering how I could “non invasively” monitor the content level of each bottle.

At the moment all I can think of is maybe some way to weigh the bottles… Use a known “full weight” and a known “empty weight” and do some sums based on the current weight.

I’d be interested to hear of any other bright ideas on how this type of thing could be done…

One thing I have to consider is that I have 2 bottles that automatically switch when 1 is empty… I’m then expected to contact the gas company who then swaps out the empty bottle with a new one… So having something that attaches to the bottle might not be ideal…

2

Load sensors to measure weight…

3

That’s pretty difficult, short of slipping a set of bathroom scales under each cylinder.

Maybe start at the other end … monitor your consumption ? Assuming on/off burners and a reasonably constant flow, be much like working out kWh

4

Are there no sensors to measure pressure in the tank? Something you put between the tank and the hose to your furnace?

5

This looks along the right lines…

6

If your tank has a guage check out tank utility, they make a wifi sensor that is working well for me.

7

Maybe look at a series of ultrasonic sensors mounted on the outside. i’m pretty sure the signal will change depending on if there is liquid or gas on the other side of the wall.

8

This seems like it might be a viable approach to monitor two 45kg bottles separately without having to attach anything physically to the bottles or gas lines…

https://learn.sparkfun.com/tutorials/iot-industrial-scale

Time to go shopping!
EDIT : Although at $50 for each load cell and needing 4 for each bottle it’ll be cheaper to pay one of my children to check the levels manually each day!