Schematic High Quality - K3ng Keyer

The schematic can be expanded with various modules depending on the builder's requirements:

Connects data and clock lines to digital pins to allow keyboard-driven transmission.

Connect a keyboard to type Morse code directly. Building the Keyer: Tips for Success

The Ultimate Guide to the K3NG Arduino CW Keyer Schematic and Architecture

The brain of the operation (e.g., ATmega328P or ATmega2560). k3ng keyer schematic

: Connected to pins like D2 (Left/Dit) and D5 (Right/Dah). When a paddle closes, it grounds the pin. Internal MCU pull-up resistors can be used, though some builders add external 10k ohm resistors for RF immunity.

When laying out your schematic on a breadboard or custom PCB, use this standard pin mapping guide for an ATmega328P (Nano/Uno): Component Feature Arduino Pin Pulls to GND when pressed Dah Input Pulls to GND when pressed Sidetone Out Outputs square wave audio TX Key Line Drives the transistor/optocoupler base PTT Line Push-To-Talk delay control (optional) Speed Wiper From 10k linear potentiometer Command Button Enters memory/configuration mode Advanced Schematic Additions

: The preferred choice for a comprehensive build. The expanded flash memory and high I/O pin count allow you to run all options simultaneously. Understanding the Schematic: Key Circuit Modules

Multiple memory slots for standard contest exchanges, CQ loops, and callsigns. The schematic can be expanded with various modules

Connect Pin 4 and Pin 5 (Emitter and Collector of the output transistor) to your radio’s key jack. Note: Ensure polarity matches your rig's manual.

: 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.

If you choose a larger microcontroller like the Arduino Mega 2560, you can expand your schematic to include advanced peripherals. LCD / OLED Display Integration

The K3NG keyer works by using the microcontroller to generate a precise CW signal based on user input from the paddle or straight key. The microcontroller processes the input and applies the selected settings, such as speed and tone, to produce the desired CW signal. The output stage then amplifies and shapes the signal to drive the transmitter. : Connected to pins like D2 (Left/Dit) and D5 (Right/Dah)

The Ultimate Guide to the K3NG CW Keyer Schematic: Build Your Own Advanced Ham Radio Keyer

A regulated 5V DC supply, often derived from a 9V-12V input.

The Dit and Dah lines from your paddle are connected to digital pins on the Arduino.