Hello,
I am sharing a Morse key decoder project based on an ATmega328P microcontroller.
This project was originally developed and discussed on the French Arduino forum.
It is presented here in English for the international community, with complete documentation
and a public repository.
Overview
The project implements:
- External Morse key input (used as a simple contact)
- Precise measurement of press and silence durations using millis()
- Binary encoding of Morse symbols (dot = 1, dash = 0)
- Decoding via a compact constant table stored in FLASH (PROGMEM)
- Real-time output on a 20x4 I2C LCD
- Adjustable Morse speed via two push buttons
- No dynamic memory allocation
- No interrupts
- No hardware timers
The design focuses on deterministic behavior, low RAM usage,
and explicit time-based logic.
Hardware
- ATmega328P @ 16 MHz
- 5 V supply
- External Morse key via mono jack (TIP / SLEEVE)
- 20x4 I2C LCD (PCF8574)
- Buzzer driven directly by a digital output
- Two push buttons for speed adjustment
Schematics and PCB photos are included.
Repository
Complete source code and documentation (English / French):