A while back I wrote about using The Owl electricity monitor and pulling out information from it’s SQLite database and graphing it using PHP. That’s working fine still and providing very useful information.
But, it’s only half the story, well, a third if you count the soon to be installed water meter, but what I mean is, we also have gas and use a fair bit of it, so it would be nice to monitor this too.
I read somewhere that the gas meter has a magnet inside it as it turns, so in theory a reed switch placed near by this magnet would create a circuit each time the magnet performs a full revolution. I used a cheap pedometer and removed the pedometer part of it so it was really just a counter. I connected a 20w 2.2mm * 10.5mm reed switch to it with some old telephone wire and fixed that to a plastic backing to give it support (The first glass reed switch didn’t last very long, I may be a touch heavy handed).
After some brief fiddling I found a spot, just under the right most digit on the gas meter that increased the pedometer by one on each full turn bingo. I really didn’t want to be hacking the gas meter apart, so the solution had to be easy to retro fit.
The next step is to find a way of recording this, my original plan was going to be via a com port and some custom c# code, but I may explore some alternative avenues before going ahead with that, watch this space. (See Part 2 here)