K3ng Keyer Schematic Official
The K3NG schematic is famously flexible, allowing builders to "enable" or "disable" hardware features in the code to match their specific build: A Simple DIY “Unikeyer” Based on the K3NG Design
Stereo jack connected to the Arduino pins for dot/dash detection.
Locate the 2N2222 transistor. Identify the Emitter (Arrow). Solder that to GND. Solder a 1k resistor from Pin 9 to the Base . Solder a wire from the Collector to your radio's "Tip" of the 3.5mm jack. Solder a separate GND wire to the "Sleeve" of the jack.
Most radios (Icom, Yaesu, Kenwood) have a "key line" that sits at +5V, +8V, or even +12V. The Arduino can only handle 40mA and 5V. Hooking it directly will release the "magic smoke."
The K3NG keyer is an open-source, microcontroller-based Morse code keyer. Unlike basic hardware keyers that offer only speed adjustments, the K3NG firmware transforms a simple microcontroller into a powerful radio interface. Key Features of the K3NG Firmware: 1 to 999 WPM (Words Per Minute). k3ng keyer schematic
Before soldering, define your pins in the Arduino IDE and make sure they correspond to your physical wiring.
Put a red box around pins 20 & 21. You don't need them for basic functionality.
The schematic is not a static document but a template for customization. By altering the wiring and the corresponding keyer_features_and_options.h file in the code, users can add: Command Buttons: For accessing memories or changing modes. Rotary Encoders: For precise speed or frequency adjustments. PS/2 or USB Interfacing: Allowing a standard keyboard to send Morse code. WinKeyer Emulation:
Requires 6 digital pins and a contrast pot, significantly cluttering the schematic. Stick to I2C whenever possible. PS/2 Keyboard Interface The K3NG schematic is famously flexible, allowing builders
+---------------+ | Microcontroller | +---------------+ | | v +---------------+ | Paddle Interface | +---------------+ | | v +---------------+ | Speed and Tone | | Controls | +---------------+ | | v +---------------+ | Memory and Storage| +---------------+ | | v +---------------+ | Output Stage | +---------------+
The sidetone allows you to hear your code without turning on your radio.
A typically shows one or two keying outputs (though the code can support up to six). Each output includes a series‑base resistor and a pull‑up to +5 V on the collector side to ensure a definite high‑impedance state when the output is off. The output jack is usually a mono 3.5 mm plug that connects to the transceiver’s straight‑key input.
Start with the minimal build (Arduino + 2 resistors + 1 transistor + 2 paddles). Once you get a "dit" on the air, add the LCD. Then add the encoder. Then add the PS2 keyboard. The schematic supports it all. Solder that to GND
The heart of the keyer is the . The schematic can be drawn for any of the common Arduino boards, but the connections generally follow a standard assignment defined in the software files keyer_pin_settings.h and keyer_hardware.h . For example, on a basic Arduino Pro Mini build, the following pin assignments are common:
This comprehensive guide explores the core K3NG keyer schematic, essential hardware components, peripheral expansions, and step-by-step assembly instructions. 1. What is the K3NG CW Keyer?
Without pull-up resistors, when the paddle is open (not pressed), the pin floats. Electrical noise from your transmitter (RFI) will cause the keyer to trigger randomly. With the 4.7kΩ resistor, the pin stays at +5V until the paddle shorts it to ground.
To interface with a transceiver, the schematic employs a switching circuit—usually an optoisolator (like the 4N25) or a simple NPN transistor (like the 2N2222). This isolates the Arduino’s sensitive logic from the potentially high voltages or currents of the radio's keying line. User Interface:
The K3NG firmware is susceptible to . If your voltage drops below 4.5V during a transmission, the Arduino resets. This is catastrophic during a contest.