K3ng Keyer Schematic Repack Fixed

Repacking the K3NG Keyer: A Fresh Look at an Open-Source Legend

If you’ve spent any time in the homebrew CW world, you know the K3NG Arduino Keyer is the gold standard. Written by Anthony Good (K3NG), this feature-packed keyer supports anything from a basic iambic paddle to a fully-featured contest keyer with a display, rotator control, and PSK31 beaconing.

• PDF (single-page, color-coded: red=power, blue=logic, green=RF)
• KiCad 7 source files (modular sheets)
• Fritzing breadboard view for rapid prototyping

• "C4 blew up when I used a 16V cap. Use 25V."
• "Don't connect the keyer ground and radio ground here—creates a ground loop. Connect at the jack instead."
• "The internal pullup on pin 8 is weak. Add a 4.7k external resistor for the straight key."

Further Reading:

• 5V/12V input options (USB vs. external DC jack).
• Reverse polarity protection diode (1N4001).
• 100nF decoupling capacitors near the microcontroller.
• 470µF bulk capacitor for keying spikes.

• Origin and community: K3NG began as a versatile Arduino-based project to provide advanced keying features beyond basic mechanical keyers. Its open-source nature has led to many community forks, hardware integrations, and detailed build guides.
• Key features: iambic A/B modes, straight key and bug support, adjustable weighting and speed control, keyer memories, Winkeyer emulation, USB serial CAT control, and compatibility with common paddles and FSK/TTL outputs.

3. The Key Output (Transistor Switch)

The simplest version uses a 2N7000 or BS170 MOSFET. A repacked schematic will show: k3ng keyer schematic repack

2.3 User Interface: Encoders, Buttons, and Potentiometers

The repack clarifies: