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Noninvasive CH4 detector

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jcooper

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I am trying to brain storm a project that would be able to sense CH4 or probably more specifically domestic natural gas flows in a low cost, noninvasive way (without violating the laws of physics ;)

There are ultrasonic detection methods that I am researching - and I think that a Doppler method has some promise as others are doing it. In this case it would be about trying to simplify the device; lower the cost/power requirement and make it easy to set up.

Other "out there" ideas are looking at the magnetic field - although I think the energy requirement is huge (trying to calculate now). Simplistically, could the molecules take on some EM energy and emit - then detect the energy decay down stream to calculate flow?

I am far from having much expertise in the area, but thought I might find folks that would like to have a dialogue about it.

By the way, this is a research project that is not commercial, it is for "open source" application funded by EU research grants.

If I am completely in the wrong community or forum any pointers would be appreciated.

Thanks in advance.
 
There is an infrared emitter 0n 1.65u, a nice absorption point for methane. Available from Farnell.Also one on 1.3u to use as a reference. It looks just the job, especially if you dont like using a lot of power. I can see it running for a long time off small batteries!
I apologise for being asleep and somehow completely missing the idea that flow rather than presence was the thing to be measured. Ultrasonic seems a good idea, Sound bursts will need to be sent in both directions and the speed found each way.
 
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What specifically is the application for? One method that would be very non invasive would be to use the utility companies meter and simple read it's signal, all the works already done for you, all you need to do is figure out how to read their meters. A simple call to a utility company technician may get you the information to safely and legally interface with their meters, some of them are fully electronic nowdays, although even the standard mechanical meters generally have spinning dials and visible sources of their flow meters. In some cases there's a simple window of a little spinning ball that rotates at the same rate of gas flow, they're exceptionally accurate or the gas companies wouldn't' use em =) If you have such a system you can access a simple reflective non contact type tach can detec the light/dark patchs of the rotating ball. Depends entirley on the meter used in your locality.
 
Yep -- you are right about this method. I should probably explore it more. There are a few meters that have very good "pulse" interfaces - either flashing LED (one pulse per unit) or a cable coupling that pulses a voltage. I probably need to do a study to understand how many are out there.

Then you are correct about the reflective idea. I guess it would have to be illuminated more or less continuously and then watch for reflection. Low power is key here.

Also, OCR type readers where a photo is taken and sent. I think that there may be a low power option for that. If you took a reading a couple of times oer day -- sent it slowly over 433Mhz radio. Cheap CCD/CMOS, infrared illuminated ...

Thanks for the ideas guys.
 
You probably already know this, but 433 MHz is an Amateur Radio allocated frequency, so you need at least a Technician (or grandfathered Novice) class license to to broadcast on this frequency.

Like I said, you probably already know this, so this is mainly for the benefit of other readers.
 
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You probably already know this, but 433 MHz is an Amateur Radio allocated frequency, so you need at least a Technician (or grandfathered Novice) class license to to broadcast on this frequency.

Like I said, you probably already know this, so this is mainly for the benefit of other readers.

We work with some products today (in Europe) that are 433Mhz -- Oregon Scientific weather station and some home automation stuff. Maybe Europe (UK) is different? Good to know for US compatibility.

Very nice to see these boards active - this seems like a good group.
 
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