Synth-DIY Yahoo! Groups Archives

Re: [AVR-Chat] Answering machine using AT89E51

2004-11-04 by David Jones

>>> heavenly_arnold@yahoo.com.sg 04/11/2004 3:58:01 pm >>>
>Dear All,
>I am about to make a small project using the features in AT89E51( in
system programmable microcontroller ). My ideas are :
>1. to record incoming phone call ( answering machine ) by feeding the
analog audio output from a telephone to an ADC
>2. Storage media will  be a HDD ( i suppose 1,2GB will be enough )
>3. LCD Display, will display how many message received , number
ID...etc
>4. capability to play back all recorder messages by selection
>5. capability to erase message one by one
>I wonder how to make a driver software for the HDD, and in what format
will the voice data be saved ( wav or...)
>Would be a great help if anybody can give me suggestion or gives me
the relevant project description.Thank's
>Regrads,
>Mansur 

I've gotta say it...
Why bother?
You could not build it yourself for less than a typical consumer
digital answering machine.
But if you want to build one for interest sake, or have a custom
application in mind...
There are single chip solutions out there, just look at the ISD range
of recorder chips for starters. Using a hard drive would be the last
thing you should be looking at. Solid state FLASH memory is by far a
better option.
1GB of memory is an insane amount for an answering machine. Even
storing an uncompressed WAV at 8KHz you'd get over 30hours of recording.
How many messages are you expecting?
If you want a custom LCD interface then by all means use an AVR to
control an ISD recorder chip.
Telephone message storage is usally compressed and around 4-8KHz
sampling rate.

Dave :)

Re: [AVR-Chat] Answering machine using AT89E51

2004-11-04 by rajesh parwani

hey, i know about how to interface a 8 bit microcontroller with hdd.

u can do that by writing a device driver for ide interface . it possible well u can go through white papers of microsoft for fat16 or fat32 driver which ever u desire

David Jones wrote:

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>>> heavenly_arnold@yahoo.com.sg 04/11/2004 3:58:01 pm >>>
>Dear All,
>I am about to make a small project using the features in AT89E51( in
system programmable microcontroller ). My ideas are :
>1. to record incoming phone call ( answering machine ) by feeding the
analog audio output from a telephone to an ADC
>2. Storage media will be a HDD ( i suppose 1,2GB will be enough )
>3. LCD Display, will display how many message received , number
ID...etc
>4. capability to play back all recorder messages by selection
>5. capability to erase message one by one
>I wonder how to make a driver software for the HDD, and in what format
will the voice data be saved ( wav or...)
>Would be a great help if anybody can give me suggestion or gives me
the relevant project description.Thank's
>Regrads,
>Mansur

I've gotta say it...
Why bother?
You could not build it yourself for less than a typical consumer
digital answering machine.
But if you want to build one for interest sake, or have a custom
application in mind...
There are single chip solutions out there, just look at the ISD range
of recorder chips for starters. Using a hard drive would be the last
thing you should be looking at. Solid state FLASH memory is by far a
better option.
1GB of memory is an insane amount for an answering machine. Even
storing an uncompressed WAV at 8KHz you'd get over 30hours of recording.
How many messages are you expecting?
If you want a custom LCD interface then by all means use an AVR to
control an ISD recorder chip.
Telephone message storage is usally compressed and around 4-8KHz
sampling rate.

Dave :)

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