How to Use HM-10 BLE Module with Arduino to Control an LED using Android App

This project establishes a wireless communication link between an Android smartphone and an Arduino Uno using the HM-10 Bluetooth Low Energy (BLE) module, allowing you to control an LED remotely. The HM-10 module communicates with the Arduino Uno via serial communication, bridging the wireless airwaves and the microcontroller's hardware or software serial pins. When you interact with the Arduino Bluetooth Controller app on your Android smartphone, specific command characters or strings are transmitted over BLE to the HM-10 module. The HM-10 receives these data packets and forwards them directly to the Arduino Uno's RX pin. A resistor voltage divider network, constructed using the 1 kΩ and 470 Ω resistors, steps down the 5V logic output from the Arduino's TX pin to a safer 3.3V logic level expected by the HM-10's RX pin, protecting the module from potential overvoltage damage. Inside the Arduino Uno, a sketch compiled via the Arduino IDE constantly monitors the serial buffer for incoming data. When a designated command character sent from the Android app is detected, the microcontroller executes conditional logic to toggle the state of the digital output pin connected to the LED, turning it on or off in real time.