COM1031 — Morse Decoder using Raspberry Pi

This embedded systems project implements a fully functional Morse Code decoder using a Raspberry Pi Pico and various hardware components including a 7-segment display, buzzer, RGB LED, button, and potentiometer. The system interprets Morse inputs and outputs corresponding characters in real time.

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Coursework Requirements Achieved (100%)

This project fully satisfies all criteria defined in the COM1031 specification:

Startup Functionality

• Displays 8 on the 7-segment display as a test, then turns off all LEDs.
• Outputs a welcome message to the serial console on program start.

Hardware Integration

• Correct circuit connections (button, 7-segment display, buzzer, RGB LED, and potentiometer) based on the lab template.

Morse Input Recognition

• Button press durations interpreted correctly:
  • dot < 250ms
  • dash ≥ 250ms
• Gap durations between signals and letters handled precisely:
  • Inter-signal gap < 400ms
  • Inter-letter gap ≥ 400ms

Character Recognition & Display

• Correctly decodes and displays:
  • 1-signal letters: E, T
  • 2-signal letters: A, N, I, M
  • 3-signal letters: S, U, R, W, D, K, G, O
  • 4-signal letters: H, V, F, L, P, J, B, X, C, Y, Z, Q
• Displays decoded characters on:
  • 7-segment display
  • Serial terminal

Error Handling

• Inputs longer than 700ms or invalid Morse combinations trigger:
  • Error message on serial console
  • Display of 8 on the 7-segment display

Buzzer Feedback

• Short beep for dot, long beep for dash
• Distinct negative sound if:
  • Input time is exceeded
  • Inputs cannot be decoded

RGB LED Feedback

• Green: valid character decoded
• Red: invalid or unrecognisable input

Time Limit Configuration

• Potentiometer allows real-time adjustment of the time limit per letter (default: 4s)
• Serial terminal displays the configured time limit
• System handles both increase and decrease in input time window

Completion Logic

• After 4 valid characters:
  • Displays decoded message in terminal
  • Plays celebratory buzzer tune

User Continuation Option

• Prompt shown:
  • Left button: Continue (reset components, restart input)
  • Right button: Exit (shutdown components)
• RGB LED indicates:
  • Green: Continue
  • Red: Terminate

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Project Structure

├── main.c               # Main implementation of Morse decoder logic
├── hardware_setup.c     # GPIO, timers, and peripheral initialisation
├── display.c            # 7-segment display encoding logic
├── buzzer.c             # Buzzer control logic
├── rgb_led.c            # RGB LED control logic
├── morse_utils.c        # Morse translation, mapping, and error handling
├── potentiometer.c      # Time control setup and tuning
├── README.md            # Project documentation