Pico W Keypad-to-LED Controller

A Raspberry Pi Pico W project that reads a 4x4 membrane keypad and drives 12 discrete LEDs.

The firmware logic maps keypad keys to LED outputs:

• Numeric keys (1-8) switch on individual blue LEDs.
• 9 turns on all blue LEDs, 0 turns them off.
• Letter keys (A-D) switch on individual red LEDs.
• * turns on all red LEDs, # turns them off.

Important: The source logic is preserved exactly from the provided code. This repository focuses on structure and documentation.

Repository Structure

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

Features

• 4x4 keypad matrix input (rows + columns).
• 12 independent LED channels.
• Group control shortcuts for blue and red LED banks.
• Wiring compatible with Wokwi Pico simulation and real Pico W hardware.

Hardware Bill of Materials

Derived from wokwi/diagram.json:

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

Build / Run Options

The provided firmware uses Arduino-style APIs (setup, loop, Keypad.h, digitalWrite, etc.).

A) Wokwi Simulation (recommended with current code)

1. Open wokwi.com.
2. Create/import a Raspberry Pi Pico W project.
3. Copy src/main.cpp into the sketch source.
4. Replace the project diagram.json with wokwi/diagram.json.
5. Ensure Keypad library is enabled in Wokwi libraries.
6. Start simulation and press keypad buttons.

B) Real Hardware (Pico W)

You can run this via an Arduino-core workflow targeting Pico W (because code is Arduino-style):

1. Install Arduino IDE or PlatformIO.
2. Install Raspberry Pi Pico/RP2040 board package.
3. Install Keypad library.
4. Select board: Raspberry Pi Pico W.
5. Wire hardware exactly as documented in docs/wiring.md.
6. Upload firmware and validate behavior.

Pico SDK Note

A CMakeLists.txt scaffold is included for repository consistency with C/C++ projects. The current source is not native Pico SDK style and would require API porting to compile directly with Pico SDK (intentionally not done to avoid logic rewrites).

Wi-Fi / Security

• This project does not use Wi-Fi in its current firmware.
• No credentials are required.
• If Wi-Fi is added later, keep credentials in a local config file excluded by .gitignore.

Note: wokwi/diagram.json is a compact checked-in scaffold; use the full provided diagram content when recreating the exact visual layout.