The K3NG Keyer is a highly versatile, open-source Morse code keyer based on the Arduino platform, developed by Anthony Good (K3NG). Because it is designed to be modular and feature-rich, the "schematic" can range from a simple breadboard setup to complex PCB designs incorporating LCDs, rotary encoders, and multi-rig switching. Core Schematic Components
Because the code runs on an Arduino, the schematic is simply the wiring map to unlock these features. You can build a minimal keyer with three wires, or a deluxe command station with 40 components. The schematic scales with you. k3ng keyer schematic
Status LED
The schematic must pull up the I2C lines with 4.7kΩ resistors to 5V. The K3NG Keyer is a highly versatile, open-source
Option B — Optocoupler (isolation):
"The what?"