🎧 Audio Source Localization Robot (ESP32 + DSP)

A real-time audio localization robot that detects and turns toward the direction of a sound source using Digital Signal Processing (DSP) techniques on an ESP32 microcontroller.

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📘 Project Overview

This project implements an Audio Source Localization Robot using a stereo I2S microphone array and the GCC-PHAT (Generalized Cross-Correlation with Phase Transform) algorithm to estimate the Time Difference of Arrival (TDOA) between two audio signals.

By computing the sound direction in real time, the robot can physically rotate toward the detected sound source. The project demonstrates an integration of real-time audio processing, signal filtering, cross-correlation, and motor control on an embedded platform.

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⚙️ System Architecture

Core Components

• Microcontroller: ESP32 Dev Kit (Dual-core, Floating-point unit)
• Microphones: INMP441 or compatible stereo I2S microphones
• Motor Driver: L298N dual H-bridge driver
• Robot Base: Two-wheel differential drive chassis

Signal Processing Pipeline

1. I2S Audio Acquisition – 24-bit stereo sampling at 44.1 kHz
2. FIR Bandpass Filtering – Removes noise and isolates target frequencies
3. FFT and GCC-PHAT – Calculates cross-correlation to find TDOA
4. Angle Estimation – Determines sound direction from time delay
5. Motor Control – Adjusts robot orientation accordingly

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🧠 DSP Methodology

Technique	Description	Role in Project
FIR Bandpass Filter	Removes out-of-band noise	Pre-processing of microphone signals
FFT / IFFT	Frequency-domain transformation	Efficient filtering and correlation
GCC-PHAT	Normalized cross-correlation	Robust estimation of TDOA
TDOA Estimation	Time difference of signal arrivals	Determines sound source direction

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💻 Software Details

• Developed in C++ using PlatformIO with the Arduino framework.

• Modular source structure:

  ├── include/
  │   ├── config.h
  │   ├── fir.h
  │   ├── tdoa.h
  │   ├── motor.h
  │   └── fft.h
  ├── src/
  │   ├── main.cpp
  │   ├── fir.cpp
  │   ├── tdoa.cpp
  │   ├── motor.cpp
  │   └── fft.cpp
  └── platformio.ini
  

• Main Loop Functions:

  1. Read I2S audio samples.
  2. Apply FIR filter to left and right channels.
  3. Compute TDOA via GCC-PHAT.
  4. Move robot toward detected direction.

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🔧 Hardware Connections

Component	ESP32 Pin
I2S WS	GPIO 15
I2S SD	GPIO 13
I2S SCK	GPIO 2
Motor1	GPIO 25, 26
Motor2	GPIO 32, 33
Enable Pins	GPIO 22, 23

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🚀 How to Run

1. Install Requirements

   • PlatformIO IDE
   • Arduino-compatible ESP32 board package

2. Clone the Repository

   git clone https://github.com/alanfellerv/Audio-Source-Localisationbot
   cd Audio-Source-Localisationbot

3. Build and Upload

   pio run --target upload

4. Run the Robot

   • Power the ESP32 and robot chassis.
   • Clap or make a sound — the robot turns toward it!

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