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Suggest me a way to decode a sounds/tones

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Member level 1
Jun 19, 2007
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Hi all,
sorry for my english :cool:
I have a question :).

I have a buzzer that emits many different sounds and, also, 3 error codes:

1°) Bip Bip Bip at 440Hz
2°) Biiip Biiip Biip at 700Hz
3°) Biiiip Biiip Biiiip at 1150Hz

I want to decode these 3 error tones.
I can't touch nothing (the buzzer, the amp) than I must use a little mic to caputre the sound/tode.

Besides, the buzzer is situated in a crowded place with people that speaks, screams etc :razz: :razz:

Is it possible to do with a PIC?

Thanks a lot and sorry, another time, for my english :oops: :oops:


Re: Sound/Tone decoder

One option is to build 3 active band-pass-filters (3-rd order should be enough), one set to 440Hz, next to 700Hz and the third to 1150Hz, followed by three peak detectors ..
Outputs from peak detectors can be connected to PIC (3 general purpose inputs) ..

The rest is just how do you program the PIC, but it shouldn't be difficult to measure the duration of a beep and distinguish from which channel it comes ..


Re: Sound/Tone decoder

Use three bandpass fileters and three XR2211 ( tone decoder ).
It works.


Re: Sound/Tone decoder

for this i think u can use an f to v convertor along with an opamp in comprator mode with preset values based on the voltage generated for the frequency input i think this will be easier

Sound/Tone decoder

i have used ne567 tone decoder for this purpose it works great 4 me

Re: Sound/Tone decoder

Thanks all for the answers :D

faraz101 said:
i have used ne567 tone decoder for this purpose it works great 4 me

With or without a microcontroller that measure the duration of the wave?

Bye ;)

Sound/Tone decoder

i used that for remote control 3 ch.i transmit the 3 different audio tones and then on the reciever end i decode those tones with ne567.

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