- AAØZZ   EZKeyer III -
       With the Four State QRP Group       
       See http://www.4sqrp.com/kits/       

A Simple CW Keyer With Advanced Features


     Custom, silkscreened enclosure made with PC boards that you solder together

     Fourteen direct-entry commands (silkscreened on bottom of case).

     Three easy-to-use memories (47, 95 and 95 characters) kept in non-volatile memory

     5 - 55 WPM or two other optional speed ranges

     Iambic A or B, Straight Key (Cootie) and Bug Emulate modes

     Beacon mode (message repeat) with selectable delay of 1 to 9 seconds

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

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

     Speed controlled by speed pot, 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 (3 x AA battery pack)

     600 Hz sidetone (may be turned off)

     Autospacing between characters (may be turned off)

     Paddle swap command

     Keyed line goes low when active

     (OPTIONAL: LOUD Piezo - off-board, inside case - with settable volume control)

     1.5" x 1.75" PCB inside a 2.75" x 3" x 1.75" case

    EZKeyer III Assembly Manual (PDF format)

    EZKeyer III Schematic (JPG format)



     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.

     "D"– Delay before message repeat.   Allows the user to select the amount of delay between
        message repeats.   Can be anything from 1 to 9 seconds.   Default is no repeats.   The keyer response from
        the command is a DIT, requesting one character, and the user responds by entering a digit from 1 to 9, representing
        the number of seconds to delay between message repeats.   Entering a zero disables message repeats.   When
        the delay is set to a non-zero value, the next message sent is repeated after waiting for the specified number of
        half-seconds.   Repeated messages are halted by pressing either paddle.

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

     "K" - Keyer/Bug-emulate/Straight-key mode.   Cycles from "Keyer" to "Bug-emulate" to "Straight-key" and then
        back to "Keyer" mode. "Straight-key" mode can use either the DIT or DAH paddle.    Response is "K" when entering
        "Keyer" mode, "B" when entering "Bug-emulate" mode, or "S" when entering "Straight-key" mode.

     "P" - Speed Pot / Paddles toggle. Default is Speed Pot.    Response is “SP” when toggled ON and “O” when toggled OFF.
        When the Speed Pot is active the speed is controlled from minimum to maximum by turning the potentiometer.
        The maximum speed when pot speed control is active is normally 55 WPM but can be limited to 32 WPM by
        installing a jumper shorting pin 1 to pin 2 (No High) of header HDR1 on the PCB. The minimum speed when
        pot speed control is active is normally 5 WPM but can be set to 15 WPM by installing a jumper shorting pin 3
        to pin 4 (No Low) of header HDR1 on the PCB. When the Speed Pot is inactive the speed is controlled by the
        paddles. Then the “S” command (Set CW Speed) can be used to set the speed or quick speed changes can be
        accomplished by tapping the paddles as described in the “S” command section.

     "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
        character is invalid.   Default is 15 WPM.

        Alternatively, 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 is 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 a 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 OFF.    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 message characters, one character at a time.   Keyer responds with 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 the keyer gives another DIT,
        indicating the space was saved in the message.   User ends the message input by entering a period.   Maximum
        size for message 1 is 47 characters.   Response is "R" after the period is entered.

     "2" - Load User Message 2.    Maximum size is 95 characters.

     "3" - Load User Message 3.    Maximum size is 95 characters.

     * 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 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 Timing Analysis (PDF)


   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)

For questions, ordering, and complete documentation see: AAØZZ Keyer (Four State QRP Group)