Use a metal "mint tin" or aluminum project box to prevent RF interference from tripping the Arduino.
This is where you connect your iambic paddle. The schematic typically uses two digital input pins, one for the "dit" (dot) paddle and one for the "dah" (dash) paddle.
Pin D11 connects to a 220-ohm resistor, then to the anode (Pin 1) of an 4N25 or PC817 optocoupler. The cathode (Pin 2) goes to GND . The optocoupler emitter (Pin 4) goes to Rig Ground, and the collector (Pin 5) goes to the Rig Key Line. k3ng keyer schematic repack
Anthony Good designed the K3NG keyer as a software-first project. The code supports dozens of pin configurations for various microcontrollers: Arduino Uno, Nano, Mega 2560, Teensy, STM32, and even ESP8266. Each microcontroller has a different pinout. Additionally, the keyer can be built with optional features like:
However, because the official project has grown to encompass hundreds of settings, the wiring schematics can sometimes feel scattered or overly complex for the average amateur radio operator. Use a metal "mint tin" or aluminum project
The K3NG keyer is one of the most rewarding projects in amateur radio. It transforms a $5 Arduino into a professional-grade contest companion. But its potential has been bottlenecked by schematic fragmentation.
Internal pull-up resistors are enabled in the K3NG firmware, so you do not need external resistors on the paddle lines. However, adding a 0.01µF ceramic capacitor from both the Dot and Dash lines to Ground is highly recommended to prevent stray RF from causing false triggering. Pin D11 connects to a 220-ohm resistor, then
To make this specific repack schematic work seamlessly, you must alter the keyer_pin_settings.h and keyer_features_and_options.h files in the K3NG source code before uploading:
: This article is for informational purposes. All DIY electronics projects carry inherent risks, including the potential for equipment damage or electrical shock. Always double-check your work and consult the official project documentation.
The K3NG Arduino CW Keyer is the gold standard for amateur radio Morse code enthusiasts. While the original project by Anthony Good (K3NG) is incredibly feature-rich, the sheer volume of options can make the schematic feel overwhelming. A "repack" simplifies the design into a practical, buildable project for the modern ham. The Core Components
: These are the most common "repacks" that bring the keyer's powerful features to life on a single PCB.