I think all the ideas expressed on these messages provide the main points for
speech processing and really the only way to figure it out is through
experimentation.
If you want phone quality speech, then you should sample at 8000 samples per
second and design your own analog circuitry for the microphone. Besides the
pre-amp and amp, you will need an antialsing filter with a cutoff frequency
around 3.6 KHz (as is used in phones). Note that the Nyquist theorem is true in
theory but in practice you need to leave some breathing room, so an antialias
filter at 4 KHz is not recommended.
It seems you don't require real-time transmission so you can certainly try to
store the samples in flash. Also it may be worth trying setting the ADC to 8
bit resolution and see if you get good quality.
Also realtime transmission may not be recommended as it has been reported in
previous emails that the radio interrrupts need to be deactivated to achieve
"high frequency" sampling. So you could acquire first and send later.
As far as compression it should be necessary to minimize power consumption
during transmission. MP3 and such may be out of the reach for motes, but
simpler schemes like DPCM with a Lloyd-max quantizer, companding and entropy
coding could be doable.
This is a difficult process to implement since many parameters need to be
tweaked in order to achieve acquisition at the desired rate(s).
Regards,
Gerardo
--- On Tue, 10/28/08, Mosab I. Messad <[EMAIL PROTECTED]> wrote:
From: Mosab I. Messad <[EMAIL PROTECTED]>
Subject: Re: [Tinyos-help] voice Recording and Transmitting in micaZ&TinyOS
To: [email protected]
Date: Tuesday, October 28, 2008, 6:07 PM
Thanks João Carlos,
First of all yea am talking about the built in microphone that comes with that
sensor board.
and as I had seen that many project have done very similar things related to
that and am trying
a project named "Microphone/Sounder Simulation" By Asuman Sunbul, and other
voice recording projects, they are almost dealing with but I think
it is not dealing with human voice, and as I have been reading its a must to
perform the sampling and
that is what am intending to do it locally to reduce the huge data and network
load since I will be
using about 4 to 5 micaZ nodes, or to perform little sample to recorded packets
directly, that makes the voice packets readable with good minimum good quality.
since after collecting these packets in the PC I will be doing some voice
processing operation on them.
---
Michael Schippling,
i think many of the voice recording are deal with the Tone Detector option for
recording, and I think it may be helpful too but still the sampling side that
may be little
confusing. but I think your advise should be tried in order to see how
effective it is and I will be trying anything :( hope I get good results.
thanks a lot for what all of you are providing me with till now .
**********************************
With My Regrads;
Mosab I. Messad
**********************************
>Date: Tue, 28 Oct 2008 12:47:05 -0600
>From: Michael Schippling <[EMAIL PROTECTED]>
>Subject: Re: [Tinyos-help] voice Recording and Transmitting in
>micaZ&TinyOS
>To: [EMAIL PROTECTED]
>Cc: [email protected]
>Message-ID: <[EMAIL PROTECTED]>
>Content-Type: text/plain; charset=windows-1252; format=flowed
>
>On the "standard" micasb board, which I believe is the MDA100, one can send
>the pre-amplified microphone signal directly to ADC2 on the mica processor
>board by turning PW6 off (by inspection of the "Mic Output Selector" section
>of the schematic). There are also tone detector options. There is no low-pass
>filtering on the raw signal so some aliasing could be expected. You can get
>an intelligible voice signal (for western languages at least) with a 2KHz
>bandwidth and 8 bits (4K bytes/sec), and you can reliably send about 100
>msg/sec with a single micaz, which comes to 2900 bytes/sec of payload.
>
>So there's your numbers...
>
>Which means that JCG's conclusion that the OP should do some kind of local
>>processing for his thesis is also highly recommended by this author.
>
>MS
>
Jo?o Carlos Giacomin wrote:
> Mosab,
>
> as far as I am concerned, MicaZ don't have a built in microphone. May
>be
> you are talking about the microphone present in MTS300/310 sensor board.
> If it is correct, I think you are not able to do what you are trying to
> do. The built in microphone of MTS300/310 is connected to a filter designed
> to
> identify the sound emitted by another MTS300/310, I think the frequency is 4
> kHz.
> You can use a MDA100 sensor board for prototiping a sound data
> collector, or you can use a MDA300. In both of these cases, you will have to
> construct the hardware around the microphone, with few resistors and
> capacitors, no more than 5 components. Then you may use HighFrequencySampling
> demo app to sample your voice. But you will have a hard work in customizing
> your program.
> Another question you must be in mind is "transmission rate".
> Human voice frequency is under 4 kHz. So you can use 8 kHz frequency
> sampling (you must do 2 samples per cycle). All the samples will be 10 bits
> long, being stored in a 16 bit variable (uint16_t). Then you will have to
> transmit about 16x8000 bits per second. 128kbps is almost the transmission
> rate limit of MicaZ (250kbps).
> Maybe, if you use only 8 bits to represent each sample, you will be
>able
> to transmit voice over MicaZ link. But you will not be able to connect more
> than two MicaZ in your network. The best choice is processing the samples
> locally in order to shrink the information before sending it through the
> network. Then this will be a very good work for your graduation.
>
>
> *****************
> Jo?o Giacomin
> Prof-DCC-UFLA
> *****************
>
> ---------- Original Message -----------
> From: Michael Schippling <[EMAIL PROTECTED]>
> To: "Mosab I. Messad" <[EMAIL PROTECTED]>, TINYOS HELP <tinyos-
> [EMAIL PROTECTED]>
> Sent: Mon, 27 Oct 2008 13:52:45 -0600
> Subject: Re: [Tinyos-help] voice Recording and Transmitting in micaZ&TinyOS
>
>> Oh, I see, there are a few messages about microphones
>> but they are not much help since most of them are questions
>> rather than answers, and the answers are mostly mine related
>> to folks not understanding what a microphone does...
>>
>> Since I haven't done anything with it I can't provide much advice
>> beyond looking at HFS or trying to free-run the ADC at a reasonable
>> rate, and then doing a buffering scheme like Oscilloscope. Message
>> transmission is quite a bit slower than audio bandwidth, and since
>> you only have a small amount of RAM to work with you can't record
>> for very long. I'm not sure if you can use the EEPROM "Log" storage
>> as it may be too slow. This may be why there are no answers...
>>
>> sorry
>> MS
>>
>> Mosab I. Messad wrote:
>>> Thanks for replaying Mr.Schippling.
>>>
>>> yea I searched every article that includes
>>> sound/recording/voice/microphone or any related feature.
>>>
>>> and I didn?t save any effort, and search place or site that related to
>>> what I need but found nothing.
>>>
>>> just talk no helpful examples :(
>>>
>>> hope one used and tested this thing help me.
>>>
>>> thanks again
>>>
>>> --------------------------------------------------
>>> From: "Michael Schippling" <[EMAIL PROTECTED]>
>>> Sent: Monday, October 27, 2008 8:55 PM
>>> To: "Mosab I. Messad" <[EMAIL PROTECTED]>
>>> Cc: <[email protected]>
>>> Subject: Re: [Tinyos-help] voice Recording and Transmitting in micaZ&TinyOS
>>>
>>>> Many have tried, search this list of audio, sound, microphone.
>>>> The HighFrequencySampling demo app in T1 is probably the place
>>>> to start.
>>>>
>>>> MS
>>>>
>>>>
>>>> Mosab I. Messad wrote:
>>>>> Slaam Alekoam,
>>>>> Hello to all, I am working on a project that includes recording
>>>>> human voice using the micaZ node using the built in microphone inside
>>>>> it and after recording, it is buffered it for 4 seconds or get sent
>>>>> direct to main mote, to be collecting in a reasonable time file all
>>>>> received samples as one file and perfrom voice processing on that file.
>>>>> my question is can any body help me and know a tested and used code
>>>>> for the voice recording and transmitting to start the voice recording
>>>>> from internal microphone process according to an interrupt signal
>>>>> send from a sensor on the sensors board and after recording it will
>>>>> be transmitted wirelessly to the main mote connected to the computer.
>>>>> or any similar code that is related to sound recoriding using the
>>>>> tinyos-1.x with micaZ motes.
>>>>> I will be very very thankful if any body could help me at least of
>>>>> part of this problem because my graduation depends on that.
>>>>> With My Regrads;
>>>>> Mosab I. Messad
>>>>>
>>>>>
>>>>> ------------------------------------------------------------------------
>>>>>
>>>>> _______________________________________________
>>>>> Tinyos-help mailing list
>>>>> [email protected]
>>>>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
>>>> --
>>>> Platform: WinXP/Cygwin
>>>> TinyOS version: 1.x, Boomerang
>>>> Programmer: MIB510
>>>> Device(s): Mica2, MicaZ, Tmote
>>>> Sensor board: homebrew
>>>>
>>>>
>> --
>> Platform: WinXP/Cygwin
>> TinyOS version: 1.x, Boomerang
>> Programmer: MIB510
>> Device(s): Mica2, MicaZ, Tmote
>> Sensor board: homebrew
>>
>> _______________________________________________
>> Tinyos-help mailing list
>> [email protected]
>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
> ------- End of Original Message -------
>
> _______________________________________________
> Tinyos-help mailing list
> [email protected]
> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
>
>--
>Platform: WinXP/Cygwin
>TinyOS version: 1.x, Boomerang
>Programmer: MIB510
>Device(s): Mica2, MicaZ, Tmote
>Sensor board: homebrew
>
>
>
>------------------------------
>
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