If you are ready to start building, I can help you narrow down the design choices. Let me know: Which do you plan to use?
A piezo buzzer or speaker for sidetone, connected via a resistor or capacitor.
: Best for standard builds with basic features. k3ng keyer schematic
#define FEATURE_COMMAND_BUTTON #define FEATURE_POTENTIOMETER #define FEATURE_SIDETONE #define FEATURE_IKLOG_BUTTONS // if using memory buttons #define FEATURE_DISPLAY_LCD // if using an I2C LCD screen Use code with caution.
| Quantity | Reference | Value / Part | |----------|-----------|---------------| | 2 | R1, R5 | 470 Ω | | 10 | R2, R4, R6, R7, R9–R14 | 1.0 kΩ | | 1 | R3 | 10 kΩ | | 1 | R8 | 100 Ω | | 3 | C1, C2, C4 | 0.01 µF (10 nF) | | 1 | C3 | 220 µF 16 V | | 1 | D1 | 1N4148 | | 1 | U1 | Arduino Nano 3.0 (16 MHz, 5 V) | | 2 | Q1, Q2 | 2N2222A or 2N3904 | | 1 | J1 | 1×4 pin header | | 1 | J2 | 1×2 pin header | | 1 | J4 | 1×3 pin header | | 1 | J6 | 1×2 pin header | | 1 | J8 | 1×3 pin header | | 1 | J9 | 1×2 pin header | | 1 | J10 | 1×5 pin header | | 1 | J11 | 1×5 pin header | | 2 | J5, J3‑PWR | (optional) LED | | 1 | J7 | 2×8 dual row header | | 1 | (optional) SW1 | Command button | | Up to 12 | SW2–SW8 | Memory buttons (or as many as you need) | If you are ready to start building, I
: The phototransistor collector and emitter connect directly to the transmitter key jack lines. 4. Sidetone Audio Circuit
If you need help, the forum is an excellent resource. Many builders post their schematic variations there, and the project maintainer (Anthony Good, K3NG) is often present to answer questions. : Best for standard builds with basic features
D8 (Key Out) ------[1k]----- Base of 2N2222 Emitter ---- GND Collector ---+----- to Radio Key Input | [10k]--- +5V (pull-up, if needed) (for radios that need high)
Supports standard paddles, straight keys, and computer keying. Understanding the K3NG Keyer Schematic