FEATURES

     Twelve direct-entry commands

     Three easy-to-use, 31 character memories kept in non-volatile memory (EEPROM)

     5 - 55 wpm speed range

     Iambic A or B, straight key, and Cootie Key modes

     Sequenced Mute Line (goes low for receiver or T/R switch)

     Default speed and modes stored in non-volatile memory (EEPROM)

     Speed entered by command or changed on-the-fly via the paddles

     Low power - 1 mA active and 1 uA in sleep mode

     Very long battery life (sleep mode when not in use) so no power switch needed

     Current speed reported upon command

     Operating voltage 3-5 volts

     600 Hz sidetone (may be turned off)

     Autospacing between characters (may be turned off)

     Paddle swap command

     Keyed line goes low when active

     1.5" x 1.75" board mounts easily in Altoids tin

    EZKeyer Schematic (JPG format)

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        COMMANDS

     Pushbuttons 1, 2 and 3 are used to send user messages 1, 2 and 3.

     Pushbutton 1 is also used to send commands to the keyer. If it is pressed and released
     quickly it sends Message 1.    If it is pressed and held for about 2 seconds before
     releasing, the keyer responds with an "R", and goes into command mode.    The user now
     enters one of these commands:

     "A" - Sidetone enable. Toggles the keyer's sidetone ON or OFF.    Default is ON.
        Keyer response is "R" in either case.

     "I" - Iambic mode toggle.    Toggles between Iambic-A and Iambic-B mode.
        Default is Iambic-A.    Keyer response is "A" or "B" for Iambic-A or Iambic-B.

     "K" - Keyer/Straight-key toggle. Toggles between "Keyer" mode and "Straight Key" mode. "Straight key" mode
        can use either the DIT or DAH paddle.    Response is "R" in either case.

     "S" - Set CW speed (between 5 and 55 WPM).   Keyer response is a DIT, requesting the first digit, followed by
        another DIT requesting the second digit.    A "T" may be entered instead of a zero.    Response is a "?" if the input
        is invalid. Default is 15 WPM.    In addition, the speed can be adjusted quickly by pressing and holding the command
        pushbutton (PB1) and then tapping the left (usually DIT) paddle or the right (usually DAH) paddle.    Each time
        the left paddle is tapped the speed increased by 2 WPM.   Each time the right paddle is tapped the speed is decreased
        by 2 WPM.    The keyer responds with a DIT after each tap.   (If PB1 is held for longer than about 2 seconds
        before the paddle is tapped, the keyer will go into command mode.)

     "T" - Tune.    Key the output continuously - until the user taps one of the paddles.

     "U" - Autospace Mode Toggle*.    Default is ON.    Response is "A" when turned ON, "N" when turned OFF.

     "X" - Swap Paddles.    The DIT and DAH paddles are reversed.

     "W" - Report Morse speed.    The keyer reports the current speed.

     "M" - Receiver Mute Mode Toggle**.   Response is "M" when toggled ON and "O" when toggled OFF.

     "1" - Load User Message 1. The user enters characters for message 1, one character at a time. Keyer sends a DIT,
        requesting a character. After the character is entered and validated, the keyer responds with another DIT requesting
        the next character, etc. If the user wants a space he just waits for about 2 seconds and it gives another DIT,
        indicating the space was saved in the message. User ends the message input by entering a period. Maximum .
        message size is 31 characters.    Response is "R" at end-of-message.

     "2" Load User Message 2.   Same as "1".

     "3" Load User Message 3.    Same as "1".

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     * Autospace Mode is an aid for sending good CW.    When enabled you cannot send CW with two dit spaces between
        any two CW elements. If you try to send two spaces it will automatically add one more, making it a letter-space instead
        of spacing within a letter. It's hard to hear unless you slow way down and try it.

     ** When ON, the receiver mute circuitry becomes operational.    Then, when the paddle is closed (either DIT or DAH)
       the RX Mute output is activated, "shorting" the jack output to ground. 7 ms later the transmitter output jack is keyed,
       "shorting" its output to ground.    After the appropriate "Dit Time" or "Dah Time" for the current CW speed the
       transmitter is un-keyed and 7 ms later the receiver mute is un-keyed.    Note that the leading 7 mS is taken away
       from the DIT/DAH "ON" time and the trailing 7 mS is taken from the inter-element "OFF" time.    The overall speed
       is constant, whether or not this feature is ON.
       For detailed timing analysis of the mute delay see:    Mute Delay Analysis (TXT format)

        NOTES

   Very easy to build with 100% through-hole parts! Build it in a few minutes

   Link to additional designer notes from AAØZZ:    Designer Notes (PDF format)