Offline Voice Modules: A Comprehensive Guide

——WangChong

Introduction

An offline voice module is a voice recognition and control device that operates without internet or cloud services. It can perform speech recognition, synthesis, and control locally, making it ideal for IoT, smart homes, robotics, and embedded systems. These modules are characterized by pre - set voice commands and fast response times.

VC-01 and VC-02 Series Overview

The VC-01 and VC-02 series, including their modules and development kits, are offline voice recognition modules from Ai-Thinker. They use the US516P6 (Fengniao M) chip from Unisound, ensuring reliability and versatility.

These modules support analog microphone input and dual-channel DAC output. They have 2MB Flash, 242KB SRAM, and integrate noise reduction technologies for high accuracy and quick responses. They also support bilingual (Chinese and English) control, making them suitable for smart homes, voice interaction, and IoT applications.

VC-01 and VC-02 Development Kits

Both VC-01 and VC-02 development kits share the same PCB base, differing only in module size. They support up to 150 offline voice commands and feature 5 GPIO outputs, I2C, PWM, DAC, and UART outputs. The GPIOs can control simple switches, while other protocols allow for complex command control with external microcontrollers.

Choosing Between VC-01 and VC-02

The VC-02 is better for size - conscious users. Schematics for both kits are available in their respective spec documents.

VC Series Development Kit Unboxing

Since the VC-01 and VC-02 kits share the same PCB, the following unboxing and demo will focus on the VC-02 kit unless otherwise noted.

The VC-02-kit includes three components: a speaker module, a microphone, and the main body. It uses a Micro-USB port for power and has two interfaces: one for speaker output and one for microphone input.

Connecting the microphone and speaker requires proper alignment of the interfaces, which are designed to prevent incorrect connections.

Conclusion

This article has introduced offline voice modules, focusing on Ai-Thinker’s VC-01 and VC-02 series. It covered their parameters, comparisons, development resources, and provided an unboxing experience of the VC-02-kit, highlighting its hardware features for developers. In the next article, I'll discuss the VC series’ pins, peripheral expansion, and factory firmware testing.