K3ng Keyer Schematic Repack Guide

A repack focuses on the Arduino Nano or Pro Mini for its small footprint. The goal is to strip away the "feature creep" of the full library and provide a rock-solid, portable foundation. 1. The Microcontroller Arduino Nano (ATmega328P). Power: 5V via USB or 7-12V via the VIN pin. Clock: 16 MHz (standard on most Nanos). 2. The Keying Circuit (Rig Interface)

I can help identify the best schematic for your chosen setup. Share public link

Because “repack” is a community-driven effort, these are not always in the official repository. Here are the top sources:

Connects to Analog Pin A2 (configured as digital input).

| Function | Uno/Nano Pin | Mega Pin | Firmware #define | |----------------|--------------|----------|-----------------------------| | CW Output | D13 (or D8) | D13 | #define cw_output_pin 13 | | Paddle Left | D3 | D3 | #define paddle_left_pin 3 | | Paddle Right | D2 | D2 | #define paddle_right_pin 2 | | Speed Pot | A0 | A0 | #define speed_pot_pin 0 | k3ng keyer schematic repack

Transistor (2N2222) connected to a PWM pin (e.g., Pin 8) to act as a switch for the radio. LCD (I2C): SDA to Pin 20, SCL to Pin 21.

Perhaps the most critical safety aspect of the repack is the keying output. The K3NG firmware supports both positive and negative keying voltages to accommodate a wide range of transceivers, from modern solid-state rigs to vintage tube transmitters. A repacked schematic highlights the isolation and driver circuitry. This usually involves a transistor driver stage (often a 2N2222 or similar) and, ideally, opto-isolators (such as the 4N35). Consolidating this into a clear output block ensures the builder understands the separation between the microcontroller’s logic ground and the transceiver’s keying line, protecting the expensive radio equipment from voltage spikes or ground loops.

The K3NG keyer supports multiple display types, and the repack shows wiring for:

The K3NG Arduino CW Keyer, designed by Anthony Good (K3NG), is the gold standard for open-source Morse code keying. While the original project is incredibly powerful, its sheer versatility can make the schematic feel overwhelming. A "repack" simplifies the design, focusing on the core features most hams actually use. A repack focuses on the Arduino Nano or

The is the preferred choice for repacked designs due to its small footprint and built-in USB port. Pin D2 : Connected to the Left (Dot) paddle. Pin D5 : Connected to the Right (Dash) paddle.

In late 2024, Anthony Good (K3NG) expressed interest in merging community repack contributions into the main repository. If successful, future keyer builders will no longer need to hunt for scattered diagrams.

The original K3NG code is modular, meaning you can strip it down or beef it up depending on your hardware. The Minimalist Arduino Nano Go to product viewer dialog for this item.

A repack typically presents this as a large table or multi-page diagram with clear cross-references. The Microcontroller Arduino Nano (ATmega328P)

The term "schematic repack" in the context of the K3NG keyer refers to the collection, organization, and explanation of the project's circuit diagrams and related hardware documentation. Because the K3NG keyer can be built in dozens of different configurations—from a minimalist keyer with only a few buttons and outputs to a fully-featured station controller with LCD screens, keypads, and multiple radio interfaces—its schematics are scattered and can be overwhelming.

This is the official support forum. In the “Files” section, you’ll find user-contributed “schematic repack” folders. Pay attention to those labeled “V2.0” or “Nano repack.”

For a new ham, trying to wire a K3NG keyer can feel like solving a puzzle where the pieces are in different rooms. A typical problem: