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Talking Clock

Discussion in 'Hobby Electronics' started by w, Oct 1, 2003.

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  1. w

    w Guest

    Hi all

    I am after a circuit diagram for a talking clock.
    Most appreciated if anyone can help.

    Jay Mather
  2. I'm not aware of any circuits around for this, except for ones based
    on the obsolete SPO256AL2 speech chip. One micro and an SPO256 is all
    that would have been needed.
    There is no adequate replacement for the SPO256, so you'd either have
    to use one of the newer chips (by Winbond I think?), an ISD voice
    recorder chip, or a micro with some external memory and prerecorded
    words sampled out into a DAC.
    I'd go for the ISD or micro solution, as the newer speech chips look
    like a pain to use.
    Some ISD chips let you record and play back multiple messages.

    Dave :)
  3. Ken Taylor

    Ken Taylor Guest

  4. onestone

    onestone Guest

    Nice One
  5. onestone

    onestone Guest

    You can do this with a single microcontroller. An MSP430F149 has 60k of
    code space. A real Time clock program needs less than 2k, depending on
    how many bells and whistles you need. Assume the worst. For a clock you
    need the words:-

    zero or ought, one, two, three, four, five, six, seven, eight, nine,
    ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen,
    eighteen, nineteen, twenty, thirty, forty, fifty, am, pm,

    26 words in total, at an average of, say 0.6 seconds per word. OR about
    16 seconds worth of speech. The MSP430 can record very high quality
    speech at 2500 bytes per second, equivalent to 2.5 bit ADPCM, but far
    higher quality. requiring 40k of memory for the calculated 16 seconds of
    speech. I estimate that even a well endowed clock, with lots of features
    would require less than 4 k of code, leaving about 56k for speech storage.

    Of course you could carve the speech up , get rid of many syllables, for
    example four + teen, eight + teen, six + teen. Would save 7 long words
    and substitute 2 short ones (fif and teen), You could get picky and do
    the same with 'ty' on twenty, thrity etc, but you don't really need to.

    Output via pwm and an R/C filter.

    Alternatively the newer MSP430F169 has a DAC for direct output to a
    small audio amp like the LM386.

    However you do it you're going to need a micro, either to control the
    external speech chip, or to impleemnt my suggestion. Since that is the
    case the Evaluation board from Softbaugh for the MSP430F169 has built in
    microphone and speaker, schematics provided, so that would allow you to
    develop the application directly.

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