Mini Yack IIc Iambic Keyer/Trainer

Introduction and Features

The Mini-Yack2c is a basic Iambic keyer based on the open source DK3LJ Yack engine, enhanced with additional features. It is designed for amateur radio operators and CW enthusiasts.

Key Features:

• Keying speed adjustable from 1 WPM to 35 WPM.
• Two memory banks, each capable of storing messages over 75 characters long.
• HF Beacon and FM beacon modes, particularly useful for 2M FM fox hunting.
• Straight key operation bypass, offering limited keyer functionality for traditional key users.
• Iambic practice modes, including a progressive mode that adjusts speed incrementally.
• Built-in speaker and a stereo headphone jack for private listening.
• Supports positive OR negative transmitter keying with a maximum rating of 200V/120mA/300mW.

Battery Installation (Assembled Units)

Batteries are included with the unit. A jumper is located on the back of the unit to disable power during shipping or long-term storage. To enable power, use a pair of tweezers or surgical clamps to move the jumper to the ON position.

To replace batteries:

1. Remove the four screws on the bottom of the unit.
2. Insert 2 AA batteries, ensuring correct polarity as indicated on the battery holder.
3. Replace the bottom panel and secure it with the four screws.

Operation

Connect your straight or Iambic key to the KEY jack. With the key depressed, adjust the volume as needed. If using the headphone/SKPR jack, always turn the volume control fully counter-clockwise before plugging in headphones. Then, with the key depressed, adjust the volume to a comfortable level.

Connect a transmitter to the XMIT jack. For detailed commands and usage, refer to the Mini-Yack operations manual.

Specifications

Current consumption:

• 1.3mA idle
• 4.8mA (no volume setting)
• 14.8mA keyed (full volume setting)

Circuit Diagram Overview

The provided circuit diagram illustrates the internal electronics of the Mini Yack IIc. Key components include an ATtiny85 microcontroller (U1, U2) which serves as the core processing unit. The unit features various resistors (R), capacitors (C), transistors (Q1), integrated circuits (U4, U5), and switches (SW1-SW5) for control and functionality. Input/output connections are provided via jacks for XMIT, KEY, and SPEAKER/HEADPHONE. Power is supplied by 2 AA batteries (BT1).

YACK Operation Manual Details

The YACK (Yet Another CW Keyer) is a universal CW keyer developed for Atmel ATTiny processors. The Mini-Yack version incorporates modifications by Jack Welch AI4SV and John Clements KC9ON.

Startup

Default settings on first power-on are IAMBIC B mode at 15 WPM. These settings can be changed using the commands described below.

Power On Behavior

The keyer responds with "HI" when powering up with an Iambic key connected or with no key connected.

Straight Key Operation

Connect a straight key to the KEY jack. A mono or stereo jack can be used. If a stereo jack is used, the ring (middle connection or DAH) should be connected to shield (ground). The keyer automatically detects a "mono" jack on power up and enters straight key mode, indicated by sending "STK". The optional external buttons PLAY1 and PLAY2 remain functional in straight key mode. However, the COMMAND button will not accept commands as no Iambic key is present.

Mini-Yack Buttons

• COMMAND: Enters command mode.
• Play 1: Plays back the contents of memory 1.
• Play 2: Plays back the contents of memory 2.
• Reset (internal button): Equivalent to powering the unit off and on. Can be used to restore settings to factory defaults.

Speed Change

Speed can be adjusted by pressing and holding the COMMAND button while operating the DIT and DAH paddles. Pressing DIT reduces speed, while pressing DAH increases speed. The keyer provides feedback with alternating dit and dah sounds while changing speed, without keying the transmitter.

Command Mode

Pressing the COMMAND button without changing speed enters command mode, indicated by a "?" character. Pressing the button again returns to regular keyer mode, confirmed by "OK". In command mode, the transceiver is not keyed, and side tone is always active. Commands can be entered as single letters. After 6 seconds of inactivity, the keyer returns to regular mode and sends "OK". Incorrect commands result in an 8-dit error signal; successful commands typically respond with "R".

Commands - Basic

• H - PLAY 1: Plays stored message 1. Returns to keyer mode upon pressing the command key.
• 5 - PLAY 2: Plays stored message 2. Returns to keyer mode upon pressing the command key.
• 1 - RECORD 1: Records to internal message 1 (up to 100 characters) at the current WPM. Message is stored in EEPROM after 5 seconds of inactivity. Choosing "1" without keying deletes the buffer.
• 2 - RECORD 2: Records to internal message 2 (up to 100 characters) at the current WPM. Message is stored in EEPROM after 5 seconds of inactivity. Choosing "2" without keying deletes the buffer.
• G - QRS -5WPM: Temporarily slows the keyer by 5 WPM. Resume current speed via Reset button or power cycling.
• Q - QRQ +5WPM: Temporarily speeds the keyer up by 5 WPM. Resume current speed via Reset button or power cycling.
• W - QUERY SPEED: Reports the current WPM speed.
• P - PITCH: Allows adjustment of the side-tone pitch. DIT and DAH paddles modify the pitch. Mode terminates after 5 seconds of no paddle input, returning to command mode.
• U - TUNE: Keys the transceiver for 20 seconds for tuning. Aborted by paddle input or control key press.

Commands - Keyer

• A - IAMBIC A MODE: Sets IAMBIC A as the permanent keying mode.
• B - IAMBIC B MODE: Sets IAMBIC B as the permanent keying mode.
• D - DAH PRIORITY: Simulates the behavior of early keyers where a sequence of DAHs is sent in a squeezed state.
• I - ULTIMATIC MODE: Sets the keyer to ULTIMATIC mode, where the last touched paddle is repeated indefinitely when squeezed.
• X - PADDLE SWAP: Swaps the DIT and DAH paddles.
• F - FARNSWORTH PAUSE: Sets an extended inter-character pause for improved readability in playback modes. This affects reception, not transmission. For transmission, manual pauses are required.

Commands – Transmitting and Tone

• I - TX INVERT: Toggles the keyer output level between positive and negative. This setting depends on attached keying circuits or radios.
• K - TX DISABLE: Toggles the TX keyer output. By default, the keyer switches the transmit line in keyer mode. This setting enables or disables that function. Keying is always off in Command mode.
• S - SIDETONE: Toggles the side tone oscillator (ON/OFF). This setting is relevant only for regular keying mode; side tone is always on in command mode.

Commands – Features

• C - CALLSIGN TRAINER: Generates 2x2 call signs (side tone only) at the current WPM. The user keys the call sign back using the iambic key. Correct entry results in "R" and the next call sign. Incorrect entry results in an 8-dit error, and the current call sign is repeated. If no input is received for 10 seconds, the keyer returns to command mode.
• Z - ADVANCED TRAINER: Similar to the calls sign trainer, but speed increases by 1 WPM on each successful entry and decreases by 1 WPM on unsuccessful entry. Pressing the command button terminates training, returns to the original WPM, and displays session statistics. Do not press command mode while the keyer is sending. The last call sign sent is not counted.
• N - BEACON MODE: After entering a number (0-9999), the keyer repeats it and sends "R". Upon returning to keyer mode, message buffer 2 is played at intervals of message length plus N seconds. This setting is preserved in EEPROM for fox hunt applications. Entering an interval of 0 stops beacon mode.
• Y - FOXHUNT MODE: When toggled, the transmitter output remains keyed down for the duration a memory is played. Toggling again resumes normal on-off-on keying for memories. This mode works with the Beacon command for setups like FM transmitters used as beacons or fox hunting boxes.

Commands - General

• R - RESET: Returns all settings to default values, except for stored messages. Restored settings include speed, Paddle Swap, TX level inversion, side tone, and TX keyer settings. Speed resets to 15 WPM in IAMBIC B mode.
• V - VERSION: Reports the current keyer software version.
• 0 - LOCK/UNLOCK: Locks or unlocks main configuration items, excluding speed and playback functions.

Hardware Reset

If control is lost due to excessive speed settings or accidental command sequences (e.g., LOCK), the keyer can be reset to factory defaults using the following procedure:

1. Power off the unit.
2. Hold the command button down and then power on the unit.
3. Press and release the reset button.
4. Release the command button.

Stored memories will remain intact after a hardware reset.

YACK Software License

This program is free software, licensed under the terms of the GNU General Public License (GPL), either version 3 or any later version published by the Free Software Foundation.

The program is distributed with the hope that it will be useful, but without any warranty, including the implied warranties of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. For more details, refer to the GNU General Public License.

A full copy of the GNU General Public License is available at: http://www.gnu.org/licenses/.

The original YACK software and instructions can be found at: http://sourceforge.net/projects/yack/.

YACK Quick Reference Guide