The input section connects your Morse code paddles (dit and dah) or a straight key to the Arduino.
Open keyer_features_and_options.h and uncomment the lines corresponding to the hardware you plan to install. For example, to add a rotary encoder, uncomment #define FEATURE_ROTARY_ENCODER . For a basic keyer without an LCD, you may leave most options commented.
Arduino Nano or Pro Mini (5V/16MHz) is recommended for its small footprint, although an Arduino Uno works perfectly for breadboarding.
Configure settings using your paddle and Morse code. k3ng keyer schematic
the features you built into your schematic (e.g., #define FEATURE_POTENTIOMETER , #define FEATURE_LCD_I2C ).
If you plan on building this circuit, let me know you intend to use and if you want to include displays or memory buttons . I can provide custom pin-out sheets or code configurations for your specific setup! Share public link
For total electrical isolation, an optocoupler (like the 4N25) is preferred. This prevents ground loops and protects the Arduino from high-voltage spikes found in older "boatanchor" radios. 3. The Paddle Inputs The input section connects your Morse code paddles
: Best for a minimalist footprint or simple Winkeyer emulation. Memory limitations mean you must disable code-heavy features like LCDs, USB keyboards, or deep memory banks.
USB interface for configuration and computer control (WinKeyer emulation) Memory storage for contest exchanges CW Decoder functionality
: Full configuration and operation via a computer terminal. Core Architecture of the K3NG Schematic For a basic keyer without an LCD, you
Unlike rigid, commercial integrated circuits (ICs), the K3NG keyer is software-defined. By modifying a single configuration file ( keyer_features_and_options.h ), you can enable or disable hundreds of features.
If your custom build isn't responding correctly, check for these three common hardware oversights:
Because the entire project is open source, you can fully customize the code and the hardware to fit your specific needs. The software is modular, allowing you to enable or disable features by simply commenting or uncommenting lines in the configuration files. This means you can start with a minimal, breadboard‑friendly keyer and later add a rotary encoder, LCD, keyboard interface, memory buttons, or a CW decoder without changing the core firmware.
Symptom: The LCD powers on, but you see black boxes or nothing. Cause: You connected the LCD's V0 (contrast) pin to ground. The schematic shows a between GND and +5V, with the wiper going to V0. Fix: Build the pot circuit. You need variable resistance to set the contrast.
: High-end schematics swap the 2N2222 for an optocoupler (e.g., 4N25 or PC817). This provides true galvanic isolation, keeping your computer/microcontroller environment separate from your radio's RF power stages. 3. Sidetone Audio Generation Getting Started with the K3NG Arduino CW Keyer 1
