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Gravity: Offline Language Learning Voice Recognition Sensor for Arduino, Raspberry Pi, ESP32 - I2C, UART


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Manufacturer Part Number:
₹1,685.04 inc. GST
₹1,428.00 ex. GST
₹1,685.04 inc. GST
₹1,428.00 ex. GST


Voice recognition, also known as speech recognition, is a computer technology that analyzes and converts spoken words or commands into editable text or executable actions. It enables individuals to interact with computers or devices through speech, eliminating the need for traditional input methods like keyboards or mice. Voice recognition technology has found applications in various areas, including voice assistants, smart homes, voice search, and voice-controlled notebooks.

The Gravity: Offline Voice Recognition Sensor is a device built around a dedicated offline voice recognition chip, enabling its use without an internet connection. It comes preloaded with 121 fixed command words and supports the addition of 17 custom command words. This versatility allows for the recognition of various sounds as commands, such as whistling, snapping, or even cat meows, making it ideal for interactive audio projects.

The module incorporates a dual microphone design, enhancing its resistance to noise and extending the recognition range. Even in noisy environments, it maintains a relatively high level of accuracy and reliability. Additionally, it includes a built-in speaker and an external speaker interface for providing real-time voice feedback on recognition results. The module supports both I2C and UART communication methods and is compatible with a range of controllers operating at 3.3V or 5V, such as micro:bit, Arduino (Arduino UNO, Arduino Leonardo, Arduino MEGA), Raspberry Pi, FireBeetle series, and more.

Designed for makers and electronics enthusiasts, this voice recognition module offers a dependable and flexible solution for voice interaction. It can be applied to various applications that benefit from voice control or interaction, including smart home appliances, toys, lamps, and robotics projects.

Differences between Offline and Online Voice Recognition

A crucial aspect of voice recognition is the voice database, which serves as a reference during the recognition process. Online voice databases are stored in the cloud and possess vast amounts of data, whereas offline voice databases are local and have limited storage capacity.

Figure: Wiring Diagram of Voice Recognition Module, Arduino Uno, and LED Light Module - I2C

Figure: Wiring Diagram of Voice Recognition Module, Arduino Uno, and LED Light Module - UART


  • Self-learning function: Control the module to learn command words by the voice, and any audio can be trained as a command
  • Support I2C and UART, with a Gravity interface
  • Compatible with 3.3V/5V
  • Built-in with 121 commonly-used fixed command words
  • The module has a built-in speaker and an interface for an external speaker, which can provide real-time voice feedback on recognition results
  • Equipped with power indicator (red) and recognition status indicator (blue)
  • Dual microphones provide better noise resistance and longer recognition distance
  • Compatible with Arduino controllers: Arduino UNO, Arduino Leonardo, Arduino MEGA, FireBeetle series controllers, Raspberry Pi, ESP32


  • Voice recognition interaction
  • Voice-controlled terminal
  • Competition and project development


  • Operating Voltage: 3.3 - 5V
  • Maximum Operating Current: <=370 mA (5V)
  • Communication: I2C/UART
  • I2C Address: 0x64
  • Fixed Command: 121
  • Fixed Wake-up Command: 1
  • Custom Command: 17
  • Learning Activation Command: 1
  • Onboard Microphone Sensitivity: -28db
  • Module Size: 49×32 mm/1.93×1.26
Package Contents
  • Gravity: Voice Recognition Module - I2C & UART x1
  • Gravity-4P I2C/UART Sensor Connector x1

Technical Specifications


Warranty Information

All the products supplied by Evelta are genuine and original. We offer 14 days replacement warranty in case of manufacturing defects. For more details, please visit our cancellation and returns page.

    1 Reviews

  • Posted by Arjun Agarwal on 26th Dec 2023


    Great product and great price.

    It works really well and got delivered very quick (since i live in mumbai itself) but still great price