K3ng Keyer Schematic [RECOMMENDED]

A is wired across the power rails. Pin 1 : Connected to +5V. Pin 2 (Wiper) : Connected to Analog Pin A0. Pin 3 : Connected to GND. Step-by-Step Hardware Wiring Matrix

Additional keying lines for controlling external amplifiers or switching sequences. 3. Implementation Tips Pin Configuration:

Symptom: The LCD powers on, but you see black boxes or nothing. Cause: You connected the LCD's V0 (contrast) pin to ground. The schematic shows a between GND and +5V, with the wiper going to V0. Fix: Build the pot circuit. You need variable resistance to set the contrast. k3ng keyer schematic

When laying out your schematic on a breadboard or custom PCB, use this standard pin mapping guide for an ATmega328P (Nano/Uno): Component Feature Arduino Pin Pulls to GND when pressed Dah Input Pulls to GND when pressed Sidetone Out Outputs square wave audio TX Key Line Drives the transistor/optocoupler base PTT Line Push-To-Talk delay control (optional) Speed Wiper From 10k linear potentiometer Command Button Enters memory/configuration mode Advanced Schematic Additions

Using an I2C 16x2 LCD requires only four wires (VCC, GND, SDA, SCL) and provides a visual readout of your speed and settings. A is wired across the power rails

The feature set of the K3NG keyer is remarkably extensive, often exceeding what is found in many commercial keyers. A quick overview of the main capabilities includes:

If you want an audible sidetone, install the sidetone transistor stage. The nKeyer schematic uses Q2 (2N2222) with a 1 kΩ series resistor from an Arduino pin (e.g., D12) to the base, and a speaker connected from collector to GND. An optional 100 µF capacitor (C5) in series with the speaker blocks DC. Pin 3 : Connected to GND

| | Value / Type | Qty | Purpose | | :--- | :--- | :--- | :--- | | R1, R5 | 470 Ω | 2 | Current limiting for LEDs | | R2, R4, R6, R7, R9-R14 | 1.0 kΩ | 10 | Pull-up / Pull-down resistors | | R3 | 10 kΩ | 1 | Analog button ladder reference | | R8 | 100 Ω | 1 | Current limiting / Speaker damping | | C1, C2, C4 | 0.01 µF | 3 | Bypass / Decoupling capacitors | | Q1, Q2 | 2N2222A / 2N3904 | 2 | Transistor buffers for keying outputs |

Connects to Digital Pin 2 (Internal pull-up resistor enabled).

For high-voltage tube transmitters (e.g., Johnson Ranger), you cannot use a 2N2222. The schematic allows for a 4N25 optoisolator . You bridge the Arduino side with a 330Ω resistor, and the transistor side connects directly to the tube rig's 150V key line.

If you need to key an (high voltage) or a modern transceiver ?