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DTMF controller — Parallax Forums

DTMF controller

ArchiverArchiver Posts: 46,084
edited 2004-02-02 06:16 in General Discussion
Hello all. I am looking to start experimenting with basic stamps.
The first project I am looking to do is a DTMF decoder. I need it to
decode two sets of 3 - 4 digits and control a relay. Very simple I
would think. What do I need to get started? Is there a place for
shareware programs available? I am not a novice constructor and many
years ago I did some code for a basic 52 board but all I need now is
something very simple for this application.

Thanks for any help, Dave KC3AM

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-02-02 06:16
    I did this very same project and it was very easy. all you need is the
    Clare M-8870-02 DTMF receiver you can check out the chip here. I used the
    M-8870-02 because it has a power down option.

    http://www.clare.com/85256A3900731315/0/0CB3DBFE7550D15A85256A2C0072B4D6?Open&Hi\
    ghlight=2,M8870-R3


    As far as a sample program goes. you may try this one out. I will leave out
    the LCD syntax because i had mine programmed with an LCD.
    This program was modified by me to your specifications. it will accept 2
    pre-defined sets of 4 digit codes. for this program i will use 1234 and
    9999. review the schematics on the link provided. it will show you how to
    interface the chip to the stamp. you need 5 lines for the interface. in the
    program you will see one output for the relay and one for a Denied Access
    LED. you may change the preprogrammed Codes to whatever you want just make
    sure there in binary. Have fun and good luck. Email if you need assistance.
    P.S. This is Really cool with a Backlit LCD !!!

    Gary Denison
    Kyocera Wireless Corp.

    '
    PROGRAM

    '{$STAMP BS2}

    digit_1 VAR Word
    digit_2 VAR Word
    digit_3 VAR Word
    digit_4 VAR Word
    Relay VAR OUT5
    D_LED VAR OUT6

    Main:
    LOW D_LED
    LOW Relay
    PAUSE 1000

    digit1
    IF IN4 = 1 THEN get_value
    GOTO digit1

    digit2
    IF IN4 = 1 THEN get_value2
    GOTO digit2

    digit3
    IF IN4 = 1 THEN get_value3
    GOTO digit3

    digit4
    IF IN4 = 1 THEN get_value4
    GOTO digit4

    '
    Receive Data

    get_value
    digit_1 = INA
    GOTO digit2

    get_value2
    digit_2 = INA
    PAUSE 500
    GOTO digit3

    get_value3
    digit_3 = INA
    PAUSE 500
    GOTO digit4

    get_value4
    digit_4 = INA
    PAUSE 500
    GOTO code1


    code1 '--(1234)----
    IF Digit_1 <> %0001 THEN code2
    IF Digit_2 <> %0010 THEN Denied
    IF Digit_3 <> %0011 THEN Denied
    IF Digit_4 <> %0100 THEN Denied
    GOTO Access_granted

    code2 '--(9999)----
    IF Digit_1 <> %1001 THEN Denied
    IF Digit_2 <> %1001 THEN Denied
    IF Digit_3 <> %1001 THEN Denied
    IF Digit_4 <> %1001 THEN Denied
    GOTO Access_granted

    Access_Granted
    HIGH Relay
    PAUSE 5000
    GOTO main

    Denied
    HIGH D_led
    PAUSE 3000
    GOTO main



    At 06:42 PM 2/1/2004, you wrote:
    >Hello all. I am looking to start experimenting with basic stamps.
    >The first project I am looking to do is a DTMF decoder. I need it to
    >decode two sets of 3 - 4 digits and control a relay. Very simple I
    >would think. What do I need to get started? Is there a place for
    >shareware programs available? I am not a novice constructor and many
    >years ago I did some code for a basic 52 board but all I need now is
    >something very simple for this application.
    >
    >Thanks for any help, Dave KC3AM
    >
    >
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