Build an ESP32 Text to Speech System without Internet

Imagine a device that can read text aloud without needing an internet connection - perfect for accessibility tools, voice alerts, or interactive embedded systems. In this project, you’ll build an ESP32 Text to Speech (TTS) system that converts plain text into spoken words using only the processing power of the ESP32 microcontroller. No cloud services, no Wi-Fi, and no dependency on mobile apps or external servers - everything runs locally.

This project is ideal for hobbyists, embedded developers, and anyone curious about making microcontrollers speak. Let’s explore how to turn an ESP32 into a standalone voice device that reads out text in natural-sounding speech.

Why an ESP32 Offline Text-to-Speech System?

Text-to-speech is commonly used in navigation systems, smart assistants, accessibility devices, and alarm systems. Most TTS implementations rely on internet services because generating natural-sounding audio can be computationally demanding. However, with modern optimized algorithms and libraries, the ESP32 - despite its humble hardware - can perform offline TTS reliably.

Doing this offline means:

• No internet connection required
• Faster response time
• Improved privacy
• Portable and standalone solution

What You’ll Need

To build your ESP32 offline TTS system, you generally need:

Hardware

• ESP32 board (e.g., Dev Module or any ESP32 with enough flash)
• I²S audio DAC / audio output module (MAX98357A or similar)
• Speaker (8Ω – 3W recommended)
• Power supply (USB or battery)
• Optional buttons or screen for user input

Software

• Arduino IDE or ESP-IDF
• Offline TTS library for ESP32 (depends on the chosen synthesis engine)

These components can be assembled quickly to form a compact voice device capable of reading text aloud.

Real -World Uses

An offline ESP32 TTS system can be used in:

• Voice alerts for alarms or sensors
• Accessibility devices for visually impaired users
• Announcements in public spaces
• Interactive voice modules for robots
• Toys or learning tools

Because it doesn’t rely on the internet, it is reliable and ideal for critical applications where connectivity is limited.

The ESP32 Text to Speech System turns a simple microcontroller into a standalone voice generator that reads text without internet dependency. It’s a powerful example of how much you can achieve with modern embedded software and the versatile ESP32 platform. Whether you want to make interactive gadgets, accessibility tools, or voice alert systems, this project gives you a solid foundation to explore speech synthesis on embedded hardware.