A 1N4007 diode across the keying line to prevent back-EMF.
FEATURE_EEPROM_EHRMAN : Saves your settings when powered off.
Building or "repacking" the K3NG Arduino CW Keyer—a world-class open-source project by Radio Artisan (K3NG) —is a rewarding way to get a full-featured Morse code keyer for a fraction of the cost of commercial units. 1. Essential Circuit Blocks k3ng keyer schematic repack
The K3NG Keyer is an open-source project developed by Anthony Good (K3NG). It is designed around the Arduino microcontroller platform and offers an incredible array of features that often surpass commercial, high-end keyers. Key Features of a Full K3NG Keyer Build CW speed control from 1 to 999 WPM.
: An 8-ohm mini speaker or piezo buzzer is connected to pin D4 through a current-limiting resistor. PCB Layout Considerations for the Repack A 1N4007 diode across the keying line to prevent back-EMF
Are you planning to build this on an or the high-capacity Mega 2560 ?
Connect the paddle to digital pins (defaults vary, but often D2/D5 or similar) with internal pull-up resistors enabled in code. Key Features of a Full K3NG Keyer Build
: Typically uses an optoisolator (e.g., 4N25) or a switching transistor (2N2222) with a 100-ohm base resistor and a small ceramic capacitor (0.01uF) to prevent RF interference.
By organizing your build into these modular blocks, the K3NG keyer becomes an incredibly approachable DIY project, giving you custom-tailored CW hardware built precisely for your amateur radio operating style.