According to the theory document you linked to, the ultrasonic range finder you listed won't do the trick, at least not without modification. The range finder just gives you the round-trip time of an ultrasonic ping. To figure out the flow rate, you need the frequency of the returned pulse. I also imagine that there is a narrow range of frequencies that will work through the copper pipe and with moving water.
There is almost definitely an off-the-shelf part that would work, not that I have any idea where to find it. I'll bet it isn't cheap (ie. > $10). Certainly, I'm attracted to the convenience of just clamping a sensor onto a pipe. The alternative is to do some plumbing (which isn't all that hard) and install a
cheap flow meter. I've got a couple of these sitting right here on my desk.
To me, the interesting part of the problem is the software that recognizes the consumption pattern of various fixtures and pulls them out of the aggregate data. I wonder what field of knowledge that is covered by. Wavelet theory?
jonsmirl wrote:[...]
Can this ultrasonic range finder for the Arduino do the trick? $1.80
http://www.aliexpress.com/item/HC-SR04- ... 4,201409_1
[...]
Theory on how they work.
http://www.engineeringtoolbox.com/ultra ... d_495.html
So when can I read about this amazing ESP hack on hack-a-day?