Voice-controlled Home Automation Using Arduino Nano, Bluetooth Communication, and MIT App Inventor

Abstract

This study presents the design, simulation, and experimental prototype of a voice-controlled home automation system that enables users to operate household electrical appliances—including a light and a DC fan—using natural speech commands transmitted from a smartphone via Bluetooth. The system architecture comprises an Arduino Nano microcontroller (ATmega328P), an HC-05 Bluetooth serial module, a single-channel relay module, and a custom Android application developed using MIT App Inventor. The mobile application performs speech-to-text conversion natively on the smartphone and transmits the resulting text string to the Arduino via the HC-05 module at 9600 baud. The Arduino firmware parses incoming commands and actuates the relay to switch connected appliances accordingly. The system operates entirely offline, with no dependence on internet connectivity or cloud-based services, making it particularly suitable for rural and low-connectivity environments. During laboratory testing, the system demonstrated consistent command recognition for instructions such as "Turn on light" and "Turn off fan" with high accuracy and response latency below one second, maintaining a stable Bluetooth connection within a range of approximately 10 metres. The complete prototype was realised at a component cost of ₹3,600, significantly undercutting commercial smart-home alternatives while delivering equivalent core functionality for basic home automation. The system’s modular design supports straightforward expansion to additional appliances, IoT connectivity, and enhanced machine learning-based speech recognition in future iterations.