EDMI Gas Meter sensor

I have a EDMI U8 gas meter (common for Australia)
And need to find a way to monitor the gas usage. There is a rotating metallic object on one of the plastic gear cogs, which I originally thought was magnetic but after buying several types of reed switches and testing them, I have concluded the object on this cog is not magnetic but a piece of metal.

So what I need to figure out is what electronic component do I need to get in order to record 1 full rotation of this gear cog?

Any input on this would be appreciated.


Hi Clinton,

Welcome to the forum :slight_smile:

A sensitive magnetometer or tachometer might be able to work, though through the enclosure you’d have to do some calibration work to make sure you get a result that you’re happy with.

Although using a camera and machine learning algorithm might be the way to go(I’d check out this guide: https://tutorials-raspberrypi.com/raspberry-pi-text-recognition-ocr/)



Hi Clinton,

I stumbled across this thread a while later, so sorry for resurrecting it, but probes like these are used to detect the beds of 3D printers for levelling, and if your material is conductive, and it’s within 5mm of the bottom of the housing, it may be able to pick it up:


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Woah, oh boy! So I’m not the only one trying to do this.
I’ve had similar discussions on the home assistant community forums.

I haven’t had success yet, but my next attempt is to try a Hall effect sensor. I picked up one plus an arduino/esp board at Jaycar and plan to test if i can get a measurement via that. Though the sensor i bought has a preset threshold and binary (on/off) output. But there are others that just report the analog value - which may be needed if the blips of the metal disc passing by are too feint.

Of course I’d love to know if you’ve got anywhere in the 6 months since this post!

Check these links below from two of the threads I’m following. One has a user in the UK with a similar meter but his has a magnet instead of the metal disc (model U6P)

Others UK experience:

My post:



I really want this to work also. I have tried Hall effect sensors and even with analog output was not able to show any meaningful change on the output.

Any other ideas appreciated, I’d love to find a way to monitor my gas/water usage with Home Assistant.

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Hi Shane49558,
I have not tried this yet, but on the last digit on the right number cogs, there is a circle hole that you could connect a IR sensor too.

The last digit has a reflective bit on the number 0, which is what you could use to count the cycle.

As for the water meter, my meter had a plastic plug on the side of it, which if you remove and put a barrel shaped reed sw into the plug hole, allowed you to read the water meter cycle.

Hope that steers you towards a solution that works for you. I would be interested to know if it works.

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Welcome to the forums Shane and welcome back Clinton.

There are many ways to tackle this project but I’d start with Clinton’s advice as I assume he has had success in the past.

Looking forward to hear how you progress!

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