ESP32 Smart Piano Trigger

This project turns an ESP32 into an interactive "piano key". It plays a sound when someone steps in front of a distance sensor (VL53L0X).

There are two versions included in this project:

1. Simple Version: Hardcoded single sound, no WiFi.
2. Advanced Version: Web interface for configuration, multiple sounds (C, D, E...), WiFi AP with Captive Portal.

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🚀 Quick Start (PlatformIO)

This project uses two separate environments. Choose the one you want to upload in PlatformIO:

1. Simple Version (env:main_easy)

• File: src/main_simple.cpp
• Features:
  • Plays /piano.wav from LittleFS.
  • Config (Trigger distance, Volume) is hardcoded in main_simple.cpp.
  • No WiFi, instant start.

2. Advanced Version (env:main)

• File: src/main.cpp
• Features:
  • WiFi Access Point: Creates "Piano-Config" (Pass: Piano1234) for 5 minutes after boot.
  • Captive Portal: Automatically opens settings page on phone connection.
  • Web Interface: Set Trigger Distance, Volume, and upload new sounds via browser.
  • Multi-Sound: Upload sounds for notes C, D, E, F, G, A, H and select the active one.
  • Persistence: Settings are saved permanently (even after reboot).

To upload:

• In VS Code (PlatformIO): Project Tasks -> env:main (or main_easy) -> Upload.
• Don't forget: Upload Filesystem Image first!

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🛠 Hardware Setup

Parts

• ESP32 DevKit V1
• GY-53 (VL53L0X) Time-of-Flight Sensor
• Speaker (8 Ohm / ?? W)
• Amplifier: PAM8403 Module (Recommended) OR Transistor (BC546B)

Wiring (Sensor)

Sensor	ESP32
VCC	3V3
GND	GND
SDA	GPIO 21
SCL	GPIO 22

Wiring (Audio - Recommended)

Using a PAM8403 amplifier eliminates "popping/clicking" noise and is much louder. ESP32 VIN (5V) -----> PAM8403 VCC ESP32 GND -----> PAM8403 GND ESP32 GPIO25 -----> PAM8403 L_IN PAM8403 L_OUT -----> Speaker

Wiring (Audio - Simple Transistor)

Note: This circuit is quiet and may cause clicking sounds on start/stop. ESP32 VIN (5V) -----> Speaker (+) Speaker (-) -----> BC546B Collector ESP32 GND -----> BC546B Emitter ESP32 GPIO25 --[1kΩ]-- BC546B Base

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🎵 Audio Files

• Format: WAV, Mono, 16-bit PCM, 22050 Hz (or 16000 Hz). (can be converted using https://audio.online-convert.com/convert-to-wav)
• Location: Put default files in data/ folder (e.g., C.wav, piano.wav).
• Optimization: Add a short Fade-In (10ms) and Fade-Out (10ms) to your WAV files to prevent clicking noises.

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📂 Project Structure

├── platformio.ini # Configuration for env:main and env:main_easy ├── data/ # WAV files (Upload this via "Upload Filesystem Image") │ ├── piano.wav # Default for simple version │ └── C.wav # Default note for advanced version └── src/ ├── main.cpp # Code for Advanced Version └── main_simple.cpp # Code for Simple Version