Schematic |link|: K3ng Keyer

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.

: Wired to a digital pin to put the keyer into configuration mode, allowing settings to be adjusted via Morse code audio menus. 2. Transmitter Keying Line (Galvanic Isolation)

For total electrical isolation between your computer/Arduino and your rig, use a :

A 10k-ohm linear potentiometer is connected with its outer pins to VCC (+5V) and GND. The center wiper connects to an analog input pin (e.g., A0). This provides real-time speed adjustments (WPM). Advanced Schematic Expansions

For amateur radio operators, the K3NG CW Keyer is the gold standard for Morse code generation. Developed by Anthony Good (K3NG), this open-source, Arduino-based keyer outperforms commercial units costing hundreds of dollars. k3ng keyer schematic

This article will dissect the K3NG keyer schematic pin-by-pin, explain why certain components are necessary, and guide you through building or modifying your own unit.

: Connects to Digital Pin 2 (standard configuration).

"The K3NG Keyer," Silas said, setting his coffee down on a stack of QST magazines. "Open-source. The holy grail of the modern shack. It’s not just a schematic, kid; it’s a philosophy."

Solder two 4.7k resistors from pins 2 and 3 to +5V. Solder your left paddle wire to Pin 2. Right paddle to Pin 3. The K3NG Keyer is an open-source Arduino-based CW

Put a red box around pins 20 & 21. You don't need them for basic functionality.

In the firmware, you map:

Connect a simple piezo element directly between the sidetone pin (often D4) and GND.

The built-in speaker pin (Pin 8) is weak. The schematic can be extended to include an LM386 audio amplifier circuit. This adds a 10k pot for volume and a small speaker. Look for "K3NG Audio Filter" schematics. This makes the K3NG keyer suitable for everything

"Did you include the memory buttons?" Silas asked, looking over his shoulder.

The K3NG Keyer schematic is a simple and robust design that provides a great learning opportunity for amateur radio operators and electronics enthusiasts. With its features and ease of use, the K3NG Keyer has become a popular choice among keyer enthusiasts.

| Feature | How it’s implemented in schematic | |-----------------------|--------------------------------------------------------------| | | Two paddle inputs with internal pull-ups, firmware timing. | | WinKeyer emulation | Serial port to PC (USB-serial on Arduino), same pins as programming. | | Contest memory | Uses EEPROM or external I2C EEPROM (optional in schematic). | | Command line interface | Serial monitor via USB. | | Beacon mode | Automatic keying – no extra hardware. | | Speed pot | Analog input with 10k pot. | | Rotary encoder speed adjust | Digital inputs with pull-ups. | | External LCD contrast control | Pot on LCD module (or software PWM). | | Key click filter | Optional RC on keying output. |