K3NG Keyer is a highly versatile, open-source CW (Morse code) keyer based on the Arduino platform, developed by Anthony Good (K3NG). Because of its modular nature, there isn't just one single "master" schematic; instead, the design scales from a simple two-paddle interface to a complex station controller with LCDs, keyboards, and multiple radio outputs. 1. Core Circuit Components
By building your own K3NG keyer, you gain a deep understanding of how CW interfacing works, giving you a custom tool that rivals commercial keyers costing hundreds of dollars.
Optoisolator (e.g., 4N25/PC817) – safer for older tube rigs: k3ng keyer schematic
How it works (per the classic schematic):
Static filled the room.
Paddles: Connected to pins (usually D2 for Left/Dit and D5 for Right/Dah) and pulled to ground.
Overview of the K3NG Keyer Schematic
Building the K3NG Keyer
He saw a symbol he recognized: an Optocoupler (specifically a 4N35). The schematic showed the microcontroller driving the LED inside the optocoupler. When the code fired, the LED lit up, triggering the internal transistor to close the keying line on the radio. K3NG Keyer is a highly versatile, open-source CW
