Ai-Thinker VC-02 Offline Speech Recognition Control Module

Ai-Thinker VC-02 Offline Speech Recognition Control Module

The Ai-Thinker VC-02 is a cost-effective offline voice recognition module designed for voice-controlled applications without requiring an internet connection. Developed by Shenzhen Ai-Thinker Technology Co., Ltd., it is powered by the Unisound US516P6 voice chip, which integrates advanced offline speech recognition algorithms for fast and accurate command execution.

The VC-02-Kit development board shares the same hardware design as the VC-01-Kit and includes an onboard CH340C USB-to-Serial converter for easy debugging, firmware upgrades, and development. It also features status indicators, wake-up light, and lamp/cooling control outputs, making it ideal for rapid prototyping.

Supporting up to 150 local offline voice commands, the VC-02 runs on a lightweight RTOS and provides rich peripheral interfaces for easy integration into embedded systems. With a 32-bit RISC core, DSP instructions, FPU, and FFT accelerator, it delivers powerful voice processing performance at an ultra-low cost.

Key Features

• Supports up to 150 offline voice commands

• Fully offline speech recognition (no cloud, no internet)

• All GPIOs configurable as external interrupts & wake-up sources

• 32-bit RISC core running at up to 240MHz

• Integrated DSP instruction set, FPU, and FFT accelerator

• 242KB high-speed SRAM

• 2MB onboard Flash memory

• Dual-channel DAC output

• One full-duplex UART (up to 3Mbps)

• Supports I2C, DAC, PWM, and multiple peripheral interfaces

• Lightweight RTOS system

• Onboard CH340C USB-to-UART for debugging and firmware updates

• Status LEDs for easy monitoring and development

Use-Case Examples

🔹 1. Smart Home Voice Control

• Voice-controlled lights, fans, and switches

• Offline operation ensures privacy and reliability

• Example commands:
  “Turn on light”, “Fan off”, “Night mode”

🔹 2. Voice-Controlled Lamps

• Touch-free lamp control for bedrooms or kids’ rooms

• Wake-up light and brightness control using voice commands

🔹 3. Small Home Appliances

• Voice control for appliances like air coolers, heaters, or purifiers

• No dependency on Wi-Fi or mobile apps

🔹 4. Toys & Interactive Devices

• Voice-responsive toys and educational kits

• Ideal for low-power, offline environments

🔹 5. 86-Type Wall Switch Boxes

• Smart wall panels with local voice recognition

• Works even during internet outages

Basic Wiring Overview

Power Connection

• VCC → 5V (via USB) or regulated supply as per board specification

• GND → Common ground

UART Communication (for configuration & debugging)

• TX (VC-02) → RX of USB-to-Serial / MCU

• RX (VC-02) → TX of USB-to-Serial / MCU

• Baud rate: configurable (up to 3Mbps)

GPIO Output (Example: Controlling a Relay or LED)

• GPIO Pin → Relay module / transistor input

• GND → Common ground

• Use GPIO to trigger appliances based on voice commands

DAC Output (Optional)

• DAC1 / DAC2 → Audio amplifier / speaker module

• Used for voice feedback or sound prompts

⚠️ Note: Use proper level matching and relay modules when controlling high-voltage appliances.

Applications

• Smart home automation

• Voice-controlled lighting systems

• Household appliances

• Toys and educational kits

• Embedded voice control projects

• DIY electronics & IoT development

Pin Description

Power Pins

• VCC / 5V – Power supply input (USB or regulated 5V)

• GND – Ground

UART Interface

• TXD – UART transmit (connect to RX of USB-Serial or MCU)

• RXD – UART receive (connect to TX of USB-Serial or MCU)
  ✔ Used for firmware upload, debugging, and configuration

GPIO Pins

• GPIO1 – GPIO5

  • Can be configured as:

    • Output (relay, LED, fan, lamp control)

    • Input (button, sensor)

    • External interrupt

    • Wake-up source

Audio Output

• DAC1 / DAC2

  • Dual-channel DAC output

  • Connect to audio amplifier or speaker module

  • Used for voice prompts and feedback

Example Wiring: Voice-Controlled Light

Voice Command: “Turn on light” → GPIO1 goes HIGH → Relay ON

Example Wiring: UART Debugging

⚠️ Important Notes

• Do NOT connect GPIOs directly to high-voltage devices

• Always use relay modules or opto-isolators

• Ensure common ground between VC-02 and external modules