K3ng Keyer Schematic

Many builders integrate the keyer into an enclosure with an LCD display, a rotary encoder, and a 3x4 or 4x4 keypad. This transforms the keyer into a powerful standalone station controller, allowing direct message composition, speed adjustment, and menu navigation without a computer.

For those seeking a more defined path, the project by N7XG offers a fantastic, ready-to-use schematic and PCB. This popular variant is built around an Arduino Nano 3.0 and includes a 5V Mini-360 buck regulator for power input, LEDs, headers, and built-in transistor drivers for keying. The full schematic is available in its manual. The parts list from the nKeyer gives specific values that are a great starting point for understanding the component requirements of a K3NG keyer. k3ng keyer schematic

Option B — Optocoupler (isolation):

Connects to Digital Pin 2 (Internal pull-up resistor enabled). Many builders integrate the keyer into an enclosure

A simple piezo buzzer or a small speaker driven through a capacitor and a current-limiting resistor. Popular PCB Implementations This popular variant is built around an Arduino Nano 3

Visualizing your WPM, sent characters, or menu settings makes the keyer highly user-friendly. Using an I2C 16x2 LCD saves massive amounts of pin real estate. Connect to Arduino Pin A4 (on Uno/Nano). SCL Pin: Connect to Arduino Pin A5 (on Uno/Nano). VCC/GND: Connect to +5V and Ground. Pin Assignment Reference Table (Standard Arduino Uno/Nano)