K3ng Keyer Schematic Site

The K3NG Keyer is widely considered the "gold standard" of open-source Morse code keyers, offering a level of versatility that rivals or exceeds many high-end commercial units

Static filled the room.

2.4 Sidetone & Speaker

• Arduino pin (PWM capable) → Low-pass filter (RC, e.g., 1kΩ + 0.1µF) → Audio amplifier (e.g., LM386) or passive piezo.
• On some simplified schematics: just a piezo buzzer with series resistor (100Ω–470Ω).

2.8 LCD Display (16×2)

• I2C version (most common in recent schematics):

  1. Overview of the K3NG Keyer

  The K3NG Keyer is not a single fixed schematic but a modular design around an Arduino (Uno, Nano, Mega, Teensy, etc.).
  It supports: k3ng keyer schematic

  Why are these required? Without pull-up resistors, when the paddle is open (not pressed), the pin floats. Electrical noise from your transmitter (RFI) will cause the keyer to trigger randomly. With the 4.7kΩ resistor, the pin stays at +5V until the paddle shorts it to ground. The K3NG Keyer is widely considered the "gold