K3NG Keyer is widely considered the "Swiss Army Knife" of Morse code keyers due to its open-source, Arduino-based design that offers a vast array of features. For many amateur radio enthusiasts, the project serves as a gateway into both microcontroller programming and advanced CW (Continuous Wave) operation. Core Schematic Components
The K3NG project has an active community on groups.io where builders share their experiences, ask questions, and provide support. The official source code and documentation are hosted on GitHub where you can also find detailed pin mapping files ( keyer_pin_settings.h ) and feature options ( keyer_features_and_options.h ). k3ng keyer schematic
A Goertzel audio input for displaying incoming Morse code. Conclusion K3NG Keyer is widely considered the "Swiss Army
A 3.5 mm stereo jack is connected as: tip → DIT (e.g., pin D2), ring → DAH (e.g., pin D5), sleeve → GND. The schematic often includes a 10 kΩ resistor from each paddle pin to +5 V and a 10 nF capacitor to ground for debouncing. The official source code and documentation are hosted
The K3NG Keyer is an open-source Arduino-based CW (Morse Code) keyer originally designed to be a flexible, high-performance alternative to commercial units. The project's true power lies in its software, which can be compiled to run on a wide range of Arduino-compatible boards, from the humble Arduino Uno and Nano to the powerful Mega 2560 and even the 32-bit ARM-based Arduino Due. The code is so flexible that an AVR microcontroller chip can be programmed directly for use in a circuit. This makes the K3NG keyer suitable for everything from a simple, standalone keyer to a sophisticated module permanently integrated into a homebrew QRP (low-power) transceiver.
Optional LCD/I2C displays, potentiometers for speed control, and pushbuttons for memories. Basic K3NG Keyer Schematic Diagram