Gas Meter - real time monitoring

[Ivan]

Out of interest, do your pulsing gas meters have an electricity supply? If so, any idea of the electricity consumption? 2W like an electricity meter? In which case, that's £2.60/yr to run (@15p/kWh)

[StBarnabas]

There is also a gas meter monitor on out 1-wire thread. The chips are still FOC for a limited period. You will also need a reflective optical sensor

[mallettron]

For some time I have been 'fiddling' with a home brew Gas meter logger which involved a reflective infra-red sensor, a PIC , RF modules, a PicAxe based data logger and much indecision on my part as to how this was all going to work - usual debate about what goes where and how/where to save the data etc. ! So bouts of enthusiasm and then project gets put away for a while so I thought Xmas would be a good time to finish it !.

From another forum (automatedhome.co.uk) I then discovered that my Actaris G4 meter was actually fitted with a magnet and therefore was already  'pulse ready'. A reed switch taped to the bottom of the plastic case by the zero digit and a meter confirmed this. Encouraged by this and to simplify my regular manual meter reading which I submit to 'imeasure' I hooked up a dirt cheap remote display using a hacked pedometer that I happenned to find in the street.

I just opened and removed the pedometer 'pendulum' switch and soldered a couple of wires to the PCB where the switch contacts were. I ran these out to my reed switch and away I went ! Within a few minutes I had a remote display !

Of course, you need to note the actual Gas meter reading when you zero the counter. The reed switch seemed to work almost anywhere around the casing and I used double sided foam tape to stick it on.

Much better than poking around a dim cupboard so thought I would share it with forum members. Now to finish my logger.

Do you think a wireless cycle computer (same idea magnet on reed switch) might work about 10ft away, saves me going out in the cold?

Ronnie

btw how does the remote sensor system work for water meters (they run cable from inside the house to a unit fixed o/s), maybe another remote sensor system?

[MikeM]

I see no reason why this technique should not work with several tens of metres of cable. The reed switch is only switching low current. As long as the water meter can operate the reed switch the same argument applies.

I used a pedometer but I am sure that cycle computers can record the total number of pulses ?

I 'think' that some cycle computers may even use magnets and reed switches ?

[wyleu]

Indeed they do.

[mallettron]

Well its a G4 meter and I made the simple one to test (pedometer and reed switch) but for the life of me I cannot get it to register. The switch needs to be in a certain direction to work and Ive tried it all over the meter (including the recess where the official sensor goes) and nothing

I will have another go later

Ronnie

[johnrae]

Ronnie,
Can I suggest that you offer a small compass to your gas meter display unit.  This will immediately show you whether or not there is some form of magnetic mechanism in operation as the wheels rotate.   From there you can then identify the best location for your reed switch based upon the area of strongest influence.  This is how I found that my meter has a rotating magnet built within its gearbox.  In mine the magnet is located at the end furthest away from the least significant digit - exactly where I didn't expect it to be, although it rotated in unison with the least digit.
jack

[johnrae]

This reed switch works great on my meter

http://www.maplin.co.uk/Module.aspx?ModuleNo=4767

Simply bend off the flange (very thin and brittle, so easy to do)
There are 4 wires, the 2 with bare ends are the reed switch, the two unbarde ends are the tamper circuit and can be cut off
Unit held in place with sticky tape and the wires connected across the internal reed switch on a pedometer; works a treat.

Now all I have to do is rig it all up via a radio system since my gas meter is about 25 meters from the house.


jack

[solarbot]

Thanks for the reed switch info - I was wondering if it was possible to log the gas meter - having got the electric meter logged with one of these: http://www.airsensor.co.uk/component/zoo/item/energy-monitor.html - I will try and build another one to use a reed switch instead of the light sensor :-)

[Automan]

I have been trying the saveometer which uses the reed switch in the gas meter or optical device for other meter types.

My meter only gives a pulse every 1 cubic foot so for me the reading is not detailed enough to judge how much a shower cost.

Also device provides no historic data for gas consumption, just a cost figure for the current month.

See thread http://www.navitron.org.uk/forum/index.php/topic,13058.0.html

Device website http://www.saveometer.com

Automan.

[ericw]

I have made several attempts to read the gas meter, first with a retro-reflective optical sensor and then with reed switches and hall effect devices none or which were sucessfull.

Picking up on this

Ronnie,
Can I suggest that you offer a small compass to your gas meter display unit.  This will immediately show you whether or not there is some form of magnetic mechanism in operation as the wheels rotate.   

I discovered that the compass needle would flip about +/- 180 degrees as the least significant digit turned, so then it was a much simpler matter of detecting this.
I got a compass with a transparent case (couple of quid on Fleabay), split an optical interrupter switch (H21A6) and glued the two halves to the top and bottom of the case so that the compass needle interrupted the beam. As the compass section rotates within the mounting plate you can turn it to get the best position

Connect to a HalfBee 2423 and you are solidly counting two pulses per revolution of the lowest digit.

[Automan]

Just a quick update on this device.

1. even if your meter produces a pulse per Cubic Foot this only send the data every 100 Cubic Feet.

2. Transmitter only send the data to display once an hour.

In other-words it is pretty useless and will not help you determine how much a shower or bath costs you.

If it worked in 1 cubic feet units which are just over 1p in value and transmitted data say every five minutes it would be great.

As it is the display just goes up in 100 cubic foot chunks e.g. £1.12 and of course a shower will not cost that much the information will not help you save money.

My one after four days says £6.72 which I admit is a little alarming!

I will email their support just to confirm that I have not made a mistake in configurations.

Automan.

I have been trying the saveometer which uses the reed switch in the gas meter or optical device for other meter types.

My meter only gives a pulse every 1 cubic foot so for me the reading is not detailed enough to judge how much a shower cost.

Also device provides no historic data for gas consumption, just a cost figure for the current month.

See thread http://www.navitron.org.uk/forum/index.php/topic,13058.0.html

Device website http://www.saveometer.com

Automan.

[KLD]

I'm also using Eric's DS2423 clone, but was lucky to find a Hall effect sensor that works well with our gas meter. It's a metric meter, and the magnet turns once for every 10L. The attached plot is created by reading the pulse counter every 5min. The peak at around 17:00h in the plot is due to heating the thermal store.
1 cubic meter of gas contains about 39.2 MJ or just under 11kWh, so that 1 pulse = 0.11kWh.
The sampling period of 5min then means, that I measure the average input power in steps of 1.3kW (which is clearly visible in the plot as "quantisation"). During many of the sampling periods, I get 5 or 6 pulses.
Now, with your metric gas meter, if you get one pulse every cubic foot, then that's almost a factor of 3 fewer than I have. If your gas intake is anywhere near ours, and the changes in that gas consumption are similar (say, heating the DHW cylinder only takes a few minutes), then the available pulse resolution will probably not be good enough to see much. And that's independent of of how you measure it.

Klaus

[gr0mit]

Here is my implementation of the same thing! http://www.txrx.org.uk/energy

It probably deserves to go into the 'bodges and hacks' forum really!  I will need to revamp the whole thing next week as we are getting PV installed and I want to do some serious analysis.

I'm also looking at a very low-cost version of the EMMA box, which seems to be heavily overengineered and grossly overpriced....Will probably base it on a couple of cheap current transformers and an Arduino or Atmel chip.
Rgds
Tim