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Topic: Toilet Flushing Recognition (Read 9508 times) previous topic - next topic

scjurgen


A microphone can work, I wouldn't drop that idea. The noise is strong it depends where you put the mic. Even a piezo should work as the flush should generate considerable vibrations. Flushing is also a time factos. So a simple cough should not trigger that (a long vomit  :smiley-mr-green: might). You don't need an FFT in that case, simple filters could do the trick if needed.

Another option is a pressure sensor, flushing will surely change pressure in many points...


scjurgen


My MIC already has band pass filter (pass band 100Hz 10KHz)

as in the last post I already mentioned, length of a flush is long. You could use 3 band pass filters on various frequencies so you distinct between various noises (to me a flush sounds pretty much white noise, so you should have signals on all of them, other rumors might/should be pretty short  and have distinct frequencies, ok, add a sign that says: don't sing). Use a moving average filter on a subsampled part of the output as they are very efficient (byte as resolution for the array should be more than enough). I also don't think you need a fast sampling rate, 1-2Khz could do the trick, maybe even lower.

I have a filter design suite on my website (choose 1st order filters, long calculations not float): http://www.schwietering.com/jayduino/filtuino/

pantonvich

I sort of started looking at this but then when on to something else

http://arduino.cc/forum/index.php/topic,20158.msg148630.html#msg148630

I did attach a piezo for a bit to my main line - and felt that I could get an indication when different water sources were on - I also got noise from walking across the wood floors but the profiles were different.

the following might also give you some ideas

http://www.google.com/search?q=Detecting+Human+Movement+by+Differential+AirPressure+Sensing+in+HVAC+System+Ductwork%3A+AnExploration+in+Infrastructure+Mediated+Sensing&rls=com.microsoft:en-us&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1

http://books.google.com/books?id=J-I0RLNph_4C&pg=PA271&dq=Detecting+and+Classifying+Unique+Electrical+Events+on+the+Residential+Powerline.&hl=en&ei=vn-UTdn3CYO40QGhurz0Cw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CEAQ6AEwAA#v=onepage&q&f=false

nickgammon

There are some really good electronics tutorials here:

Passive RC high pass filters

http://www.youtube.com/watch?v=4CcIFycCnxU

Passive RC high low filters

http://www.youtube.com/watch?v=OBM5T5_kgdI

He explains, he demonstrates, he shows the theory and the calculations, and he has a cat!
Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

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