Bluetooth Relay ON/OFF Project is a simple Android application that allows you to control a relay and switch ON/OFF devices such as lights and fans. Developed by Hobbyprojects.com, this free app utilizes an 89c2051 Micro-controller and an HC-05 Bluetooth Module.

To get started, make sure your HC-05 Bluetooth Module is paired with your mobile device using the default password "1234" or "0000". Refer to the manual of your Bluetooth module for further instructions.

Once paired, the app provides two buttons for controlling the relay. Pressing the ON button sends the data "A" to the Bluetooth Module, which triggers the Micro-controller to turn ON the relay. Conversely, pressing the OFF button sends the data "a" to turn OFF the relay.

Additionally, the app offers a voice command feature. Simply click on the microphone icon and speak "ON" or "OFF" to control the device. However, please note that this feature requires a WiFi or data connection.