How do they do that?

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Robert Reed
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How do they do that?

Post by Robert Reed » Sat Oct 15, 2011 8:54 pm

The utility company recently replaced my water meter and also rigged it up with a remote outdoor unit to read usage. This consists of a small clear plastic attachment mounted to the meters face. To this is attached a 3 conductor cable run outdoors to a wall mounted unit about the size and shape of small hockey puck. This unit is then scanned once a month for the meter reading. There is no external power applied to it and according to the water company, no batteries to replace. There is no hard wired connection to the meter either. So?

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Janitor Tzap
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Re: How do they do that?

Post by Janitor Tzap » Sat Oct 15, 2011 9:50 pm

It's a inductive pickup type system.

Experiment:
Take two coils of wire, place them close together.
Drive one coil with an audio generator at 1Khz.
Connect the other coil to a small 8 ohm speaker.

Now, as you move the two coils closer together.
The 1Khz signal can heard coming from the speaker.

This is basically what the scan-tool is doing.
It is inductively driving the second coil circuit.
That sends back a serial data signal that the coil on the scan-tool picks up.

This is similar to the ID chips that Dog's, Cat's and some other animals.
Have placed in them.


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Smoke_Maker
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Re: How do they do that?

Post by Smoke_Maker » Sun Oct 16, 2011 6:50 am

Goggle Firefly water meter, they have a small battery inside that last 8 years in most cases, people used to walk from house to house reading meters now the water company drives by the house slowly with a special antenna on top of the vehicle and the meter wakes up every second and transmit a low power signal with the water usage in the signal to the computer in the vehicle

It is another case of technology taking jobs but the people that used to walk from house to house are now installing the new meters and soldering components on a circuit board, be flexible things change. :grin:
Richard Furniss
is it suppose to smoke like that ?

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Janitor Tzap
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Re: How do they do that?

Post by Janitor Tzap » Sun Oct 16, 2011 10:29 am

Smoke_Maker wrote:Goggle Firefly water meter, they have a small battery inside that last 8 years in most cases, people used to walk from house to house reading meters now the water company drives by the house slowly with a special antenna on top of the vehicle and the meter wakes up every second and transmit a low power signal with the water usage in the signal to the computer in the vehicle

It is another case of technology taking jobs but the people that used to walk from house to house are now installing the new meters and soldering components on a circuit board, be flexible things change. :grin:
Hmm.....

Interesting.....
I looked at the battery spec's for the Firefly water meter.
The Lithium Battery has a maximum life span of 12 to 15 years.
Thus,
They are expecting the mechanical part to wear out,
or be replaced long before the battery dies.

The system that I have described was on a house that I lived in some 15 years ago.
It replaced the old plug in style that simply had the jack on the outside of the house
that the meter reader plugged into.

The old plug in style had issues with the contacts getting dirty,
or corroded at the plug in block because it was exposed to the elements.

I saw a meter reading system, quite some time ago now.
It used the copper piping in an Apartment building.
To send the signals from each meter in the individual apartments,
to a central receiver in the basement.
But now with plastic piping, and the cost of copper being so expensive.
This system just isn't do able.


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Smoke_Maker
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Re: How do they do that?

Post by Smoke_Maker » Sun Oct 16, 2011 6:22 pm

[quote="Janitor Tzap"]
I looked at the battery spec's for the Firefly water meter.
The Lithium Battery has a maximum life span of 12 to 15 years.
Thus,
They are expecting the mechanical part to wear out,
or be replaced long before the battery dies.

12 years :lol: they lie, they lie, they lie, there are used car salesmen (sorry saleperson) and right above them is battery sales "person"

May be the new ones will only time will tell.

The mechanics and the firefly are separate and the mechanics will out last the battery almost all the time IMHO.
Richard Furniss
is it suppose to smoke like that ?

Robert Reed
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Re: How do they do that?

Post by Robert Reed » Sun Oct 16, 2011 9:20 pm

OK guys, so you are saying that the system does in fact have power by virtue of a lithium battery (button?). Now how does that electronics receive its data from the meter. From the postings, I am assuming that the meter has some sort of rotating coil that inductively couples a signal pulse to the top mounted detector and a counter/totalizer sums and stores these pulses for the meter reading. Maybe each pulse would be 1/10 gallon. Is that correct?

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Smoke_Maker
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Re: How do they do that?

Post by Smoke_Maker » Mon Oct 17, 2011 4:10 pm

Robert, you got it. The meter has gears to change the numbers when the water flows and one of the gears has a embedded piece of metal to trip the pulse sensor.
Richard Furniss
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Robert Reed
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Re: How do they do that?

Post by Robert Reed » Mon Oct 17, 2011 8:51 pm

Ah-So. Very clever and best of all, it keeps the meter reader out of my house!

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