Hello Everyone,
Has anyone managed to attach a sensor to this meter for being able to monitor gas usage?
I tried with the popular magnet ones which use to work for other meters. However, it seems it doesn’t do the job with this specific model. Any position advice or other method suggestion?
TIA
I’ve a Schlumberger G4 Gallus 2000:
with a reed switch allocated in the hole under the second wheel from the right where the magnet is suposed to be
the reed switch is attached to a esp32-cam with i2c configured in esphome, I can also take photos with the measurement.
The reed switch should be smaller enough to be allocated inside the hole, I use this:
https://www.amazon.es/gp/product/B07Y9SW7DD/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1
If you want more information, let me know.
Hey @lerele!
Thanks for your feedback. Unfortunately, my meter has not any hole under the display:
This is a photo I just took. I guess your model has an additional feature for the purpose.
I am not sure whether this grey thing is hiding the hole you have, but that grey plastic thing is sealed with an official stamp, so I cannot open it to check. I guess I will have to try another approach, althoug I am sure which one. 
I cannot try the camera option, because the meter is installed outside my landed house. That’s the reason I need something more simple. What I wanted to do is to attach a sensor to a window battery one (the usual Aqara ones). As far as I know, the can be used for this, because a template sensor can be set up for the counter to be increased one unit everytime a contact closure happens.
Mayte you can try with a magnetometer like this one:
https://github.com/tronikos/esphome-magnetometer-water-gas-meter
That could be a good option indeed! Only thing is that I’ll have to find a way to battery power it… or perhaps I can run a cable for the magnetometer part only. Will think about it and do some research. but it will be worth it to try first whether the magnetometer works with this specific meter. It is cheap and I have a few ESP32 lying around, so will do it asap. Thanks a lot!
I just checked the magnetic field behaviour of the meter with my phone when gas is running, and this is the result, so it definitely should work!
De nada.
A little bit off-topic question:
Has any inspector seen your cables attached to the meter? Have they told you something like you cannot attach any third party cable or device to the meter or so? I am not sure whether yours is inside your place. Mine is outside because it is a landed house. The sensor is not easy to be seen though. I tried to hide it as much as possible:
I don’t think anyone sees it as it is at knees height. However, I am curious to know what they usually do when they see a sensor like this. I honestly believe that this is not illegal. The sensor is not even touching the meter at all, just the support. However, you know how these kind of workers could be and they usually know what they are trained for only. If they see anything out of their knowledge, they will probably think that the meter counter is being tampered… I hope I am wrong!
Mine is inside home, and the inspector has not seen it, but sure, when I have to pass the 5 year inspection, I will remove it to avoid problems.
How did you power up the sensor in the end, with batteries or installing wires? I have this same gas meter and could potentially run a cable alongside the gas pipe given there’s room around it but I’m concerned this might bring trouble on the next inspection.
Installing wires. Battery lasts less than a single day. I guess this specific sensor needs quite a lot of continuous power to work. I managed to hide it quite good and no issues in the 2-3 months I used it. However, this system makes the values to offset quite often, so I eventually took it out.
Good to know that that path didn’t work out well in the end, might save me some trouble. For now I’m using another approach that should work decently once calibrated properly: I have the boiler plugged to a smart power meter and thus can measure its energy usage in real time, which after some calculations I can map to actual gas consuption.
In my boiler (Intergas Kombi Kompakt 36/30) at least, the configurable min & max power percentages for the burner are tied to the configurable min & max pumping power (apparently linearly), so by playing with the values for quite some time and measuring the watts used in each scenario, I can now determine quite accurately the power level the burner is in at any given moment. And then by observing the gas meter with a stopwatch in hand and measuring the time it takes to consume 0.01 m3 (1 full spin of the lowest digit) on the lowest and highest power level configured, I can create a virtual energy sensor with the Powercalc integration and calculate estimated kWh or m3 usage. So far my virtual gas meter is roughly within ~0.1 m3 of the real value every 24h, which is not perfect but it will get better once I improve the mappings, but I’m simultaneously playing with the boiler settings for optimization purposes so I’m not pursuing the highest accuracy yet. Unfortunately DHW usage can throw off the calculations a bit given that my boiler that has its own separate burner power settings and there’s no pumping involved, so telling hot water usage apart from heating by just looking at energy usage can be tricky sometimes.
