Raspberry Pi Pico W Keypad-to-LED Controller

A keypad-driven LED controller for Raspberry Pi Pico W (RP2040).

This repository is cleaned and documented from the provided source and Wokwi hardware diagram, while preserving firmware behavior.

Project Type and Framework

The provided firmware is C/C++ using Arduino-style APIs (setup(), loop(), Keypad.h).

• Target hardware: Raspberry Pi Pico W
• Recommended build/upload path: Arduino IDE (Arduino-Pico core) or PlatformIO
• Included: Pico-style repository structure with documentation
• Included CMakeLists.txt: structure placeholder for future Pico SDK migration

Repository Structure

.
├── CMakeLists.txt
├── include/
├── src/
│   └── main.cpp
├── docs/
│   ├── architecture.md
│   ├── wiring.md
│   └── wokwi/
│       └── diagram.json
└── README.md

Features

• Reads a 4x4 matrix keypad (16 keys).
• Controls 12 LEDs mapped to keypad actions:
  • 1..8 turn on individual blue LEDs
  • 9 turns ON LEDs 1..8
  • 0 turns OFF LEDs 1..8
  • A..D turn on individual red LEDs
  • * turns ON red LEDs A..D
  • # turns OFF red LEDs A..D
• Maintains non-blocking polling loop (10 ms delay per cycle).

Components (from diagram)

• 1x Raspberry Pi Pico / Pico W board
• 1x 4x4 membrane keypad
• 12x LEDs (8 blue + 4 red)
• 12x 220 Ω resistors (LED current limiting)
• 4x 1 kΩ resistors (keypad row pull-ups to 3V3)
• Jumper wires

GPIO Mapping Summary

Detailed table is in docs/wiring.md.

• LEDs: GP11, GP10, GP9, GP8, GP7, GP6, GP5, GP4, GP3, GP2, GP28, GP27
• Keypad rows: GP26, GP22, GP21, GP20
• Keypad cols: GP19, GP18, GP17, GP16

Build/Flash on Real Hardware

Option A: Arduino IDE (recommended for current code)

1. Install Arduino IDE.
2. Install Arduino-Pico board package (Raspberry Pi Pico/RP2040 core).
3. Install Keypad library from Library Manager.
4. Select board: Raspberry Pi Pico W.
5. Open src/main.cpp (or copy content into an Arduino sketch).
6. Upload to Pico W.

Option B: PlatformIO

1. Create a PlatformIO project for raspberrypi / Pico W with Arduino framework.
2. Place src/main.cpp in src/.
3. Add dependency Keypad.
4. Build and upload.

Run in Wokwi

1. Create a new Raspberry Pi Pico project in Wokwi.
2. Replace the generated diagram.json with docs/wokwi/diagram.json.
3. Use the C++/Arduino firmware from src/main.cpp.
4. Start simulation and press keypad buttons to observe LED behavior.

Notes on Wi-Fi

• The current firmware does not use Pico W Wi-Fi.
• If Wi-Fi is added later, keep credentials in a separate local config file (excluded via .gitignore) and never hardcode secrets.

Behavior Preservation

Core logic in src/main.cpp is preserved from the provided code; only repository organization and documentation were added.