Gravity: Offline Voice Recognition Sensor (121 Built-in Commands + Custom Commands)

The Gravity Offline Voice Recognition Sensor enables local keyword-based speech control without requiring an internet connection or cloud service. Featuring 121 built-in English commands alongside custom voice-learning capabilities, it connects via I2C or UART to micro:bit, Arduino, and ESP32 microcontrollers. It is ideal for students, makers, and educators building responsive robotics and smart home automations.

Plug-and-play controller compatibility

The module supports both I2C and UART communication with an operating voltage range of 3.3V to 5V. It integrates easily with Arduino UNO, micro:bit, and ESP32 boards using dedicated Arduino IDE and MakeCode tutorials.

121 pre-programmed command words

A built-in library of 121 standard English commands is ready to use immediately without manual configuration. Common instructions like 'Turn on the light' and 'Open the door' allow rapid deployment in educational and home automation scenarios.

Trainable custom command recognition

A built-in self-learning function allows users to record and store up to 17 customised command words. Commands can be trained in any spoken language or distinct sound by entering learning mode and repeating the trigger word three times.

Integrated microphone and speaker hardware

The compact 49 by 32 mm module integrates an onboard microphone with minus 28 dB sensitivity and an onboard speaker. This self-contained design eliminates complex external audio wiring and keeps project layouts neat.

Offline operation and voice feedback

Speech processing takes place locally on the sensor to maintain privacy and operate reliably in environments without internet access. The onboard speaker delivers real-time voice feedback to immediately confirm recognised commands.

Hardware refinements and mounting options

The sensor board features dedicated mounting holes for secure attachment into project chassis and enclosures. An updated plug-and-play speaker connector simplifies assembly and hardware modifications.

Video

Downloads & documentation

• Product wiki (DFRobot)