Comments on: PyS60 DTMF Detector

By: Abilash ov frm india -kerala

Abilash ov frm india -kerala — Tue, 03 Jan 2012 07:50:45 +0000

Hai, iam from india.Iam a plus two student.Now iam learning python.Can you give me a simple dtmf app.If i can controll another s60 via my phone

By: Vishal

Vishal — Wed, 14 Dec 2011 10:47:45 +0000

Hi,

Sorry to post a question on old chain.

Can I please know, what item corresponds to “GOERTZEL_N” in Goertzel algorithm? Is it normalizedfreq?

Also, if we want to calculate in “normalizedfreq = freq / SAMPLEFREQUENCY;” for Goertzel algorithm, I assume “freq” is nAvgBytesPerSec and “SAMPLEFREQUENCY” is nSamplesPerSec in FMT chunk wav file. Please correct if I am wrong.

Using this I am trying to understand what should be the correct value for GOERTZEL_N to be used in your python script.

Thanks.

By: SteveK

SteveK — Wed, 24 Aug 2011 01:11:43 +0000

I had the same problem. The only audio samples I could get to work were 16 bit 8k sampling mono.
Once I used the correct format, this error went away.

By: etherton

etherton — Wed, 03 Aug 2011 05:50:07 +0000

It’s in the blog post. I was using 2.2.

By: Bharat Goyal

Bharat Goyal — Wed, 03 Aug 2011 05:48:34 +0000

What version of python you ran it onto?

By: etherton

etherton — Wed, 03 Aug 2011 02:53:41 +0000

So I honestly don’t understand the math in the Goertzel algorithm well enough to know exactly what you should do, so I’d start by setting self.SAMPLING_RATE to 11025 and then try playing with the self.GOERTZEL_N between 92 and 210 until it works.

For the error regarding unpack. Do you know what raw contains when it’s passed into struct.unpack()? I suspect you’re using a newer version of python than when I wrote the library, and maybe file.readframes(1) is returning something different.

By: Bharat Goyal

Bharat Goyal — Tue, 02 Aug 2011 06:35:55 +0000

I have been trying this for a while. Is it necessary to have the audio samples at 8/16 KHz.. I have testing it for a file having an audio sample at 11025 Hz, also I get errors with the variable ‘raw’ -

line 324, in getDTMFfromWAV
(sample,) = struct.unpack(“h”, raw)
error: unpack requires a string argument of length 2

By: etherton

etherton — Tue, 07 Jun 2011 05:40:00 +0000

I’m afraid I haven’t worked on this in a long time, but I’m sure if you google “DTMF wav file” you’ll find some wave files that will work.

By: Charles

Charles — Sun, 05 Jun 2011 23:33:58 +0000

Please can you make the wav files available also?

By: sachin jain

sachin jain — Mon, 25 Apr 2011 09:09:30 +0000

sir made dtmf based project but i have no idia of dtmf decoder plz tell me work of dtmf decoder\encoder