Keyer Schematic Repack — K3ng
Do you plan to build this on a ? What specific radio model are you planning to key?
This version is typically built on an Arduino Nano and is perfect for a first-time builder. It forms the foundation for many of the more complex PCBs.
Overlooked in many fragmented schematics, a repack includes: k3ng keyer schematic repack
PCB design
Build the circuit on a solderless breadboard first, following the pin connections in section 2. Do you plan to build this on a
Dedicated headers for up to 12 memory macros and a speed potentiometer for on-the-fly WPM adjustments (1–999 WPM range). 🛠️ Key Hardware Features Included: yu7aop/K3NG-Arduino-Mega-CW-keyer - GitHub
The K3NG keyer is one of the most rewarding projects in amateur radio. It transforms a $5 Arduino into a professional-grade contest companion. But its potential has been bottlenecked by schematic fragmentation. It forms the foundation for many of the more complex PCBs
The paddle lines require hardware filtering to prevent RF energy from triggering false dits and dahs.
: Demonstrating how versatile the code is, builder KK9JEF dramatically simplified the circuit to its absolute essentials, fitting everything into a 1-gang plastic junction box. He omitted the LCD, keyboard support, and practice modes, using the keyer as a generic ultimatic-style keyer with sidetone and a speed pot, all powered by 4 AA batteries. This version is a perfect example of how you can "repack" the software to work with the simplest possible hardware.
Not all repacks are equal. Some may contain if the redrawer accidentally swapped pins or omitted a pull-up. Always compare the repack against the official schematic or the keyer_pin_settings.h configuration file from the source code.
| Feature | How to Include in Schematic | Schematic Complexity | | :--- | :--- | :--- | | | Connect two pins from the encoder to Arduino digital I/O pins. Use a simple RC filter (resistor + capacitor) for hardware debouncing. | Low | | LCD Display (4-bit) | Connect the display's RS, E, D4, D5, D6, D7 pins to six Arduino digital I/O pins. Include a potentiometer for contrast adjustment. | Medium | | I2C LCD Display | Connect only the display's SDA and SCL pins to the corresponding pins on the Arduino (A4, A5 on Uno/Nano). Much simpler than 4-bit mode. | Low | | PS2/USB Keyboard | For PS/2, connect Clock and Data pins to Arduino digital I/Os. For USB HID, use an Arduino Leonardo or Due which natively supports it. | High | | Numeric Keypad | Connect an external 3x4 or 4x4 matrix keypad. Requires connecting 7 or 8 digital I/O pins to the keypad's row/column lines. | Medium | | External Memories | Connect up to 7 external switches (momentary buttons) between digital I/O pins and ground. Include 10kΩ pull-up resistors in the code or schematic. | Low |