Gasmeter readings

I am now happily running Emoncms on my raspberry Pi (only reading of electricity values is done on the Pi which then sends them through a python script to my Emoncms installation on my webserver).


I really want to start measuring my gas consumption which, due to taxes, is causing the highest bills in my area. The main problem is that I cannot find any information on my gasmeter. It is an G4 meter made by Ermaf BV in Rotterdam. I do not know if I need a reedswitch, or maybe an optical reader.

Anyone able to provide me with some advice? Pictures of the gasmeter below.



Schism's picture

Re: Gasmeter readings

I don't know anything about the specific meter I'm afraid, but I went through a similar struggle recently:

I now have a stable gas pulse counter using optical detection of the silvered zero digit on my meter, you may be able to do something similar?

alco's picture

Re: Gasmeter readings

Hey Dutchman :)

I believe that your gasmeter is an old one (no smartmeter) and has a pulse count with a magnet and reedsensor in it. so you can do it on 2 ways:

  1. Buy a hall-sensor that "catch" the magnet in your gasmeter and count that pulses. (google on hall-sensor arduino). The are cheap, about 2 euro's on ebay. see emon forum:
  2. Catch the silver [0] in the last wheel. you need a good optic sensor for it. I use an "robot infrared sensor" for smal distances ( 1cm!) on my watermeter and it works perfect (ebay link).


p.s. a small trick to detect if your gasmeter is using a magnet? take a compass (or smartphone with compass app!) and move it around the gasmeter. Does it spins weird if you go around the digits? than a magnet is present. I tried it with a Iphone 4 and that workes..but a old analog compass are more sensitive than smartphones..

fversteegen's picture

Re: Gasmeter readings

Thanks @Schism and @alco. Will try to figure out if it has a magnet. I am however very certain that there isn't any reflective mirror or whatsoever on any of the digits (have been looking at it for quite a lot of turns now).

Schism's picture

Re: Gasmeter readings

There is one more option which you may or may not like - it may be possible to get a regular gas engineer to fit you a subsidiary meter on the domestic side of your supply meter. I was considering this as a fall-back until I got the reflector method working.

Surprisingly, the actual meters are not that expensive. See i.e.

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