Bluetooth Modules

1. Definition

Bluetooth Modules enable short-range wireless communication between microcontrollers (like Arduino, ESP32) and other devices such as smartphones, laptops, or PCs.
They are commonly used for wireless control, data exchange, and IoT projects.

Popular modules include HC-05 and HC-06.

Bluetooth module examples

2. Types of Bluetooth Modules

  • HC-05 → Can act as Master or Slave (two-way communication).
  • HC-06 → Works only as Slave (simple pairing with Master device).
  • BLE Modules (like HM-10, ESP32 built-in) → Support Bluetooth Low Energy, better for low-power IoT.

3. Pin Configuration (HC-05 / HC-06)

  • VCC → Power supply (3.6V–6V, typically 5V).
  • GND → Ground.
  • TXD → Transmit data (to Arduino RX).
  • RXD → Receive data (from Arduino TX, use voltage divider if 5V).
  • EN/KEY (optional) → Used for AT Command mode (configuration).

4. How It Works

  1. Connect the module to Arduino (TX ↔ RX).
  2. Pair it with a Bluetooth-enabled device (phone/laptop).
  3. Use a serial communication app to send/receive data.
  4. Arduino processes the received data and performs actions (e.g., turn on LED, control motor).

5. Applications

  • Wireless robot control.
  • Home automation (lights, fans, appliances).
  • Wireless sensor data logging.
  • Remote-controlled cars/drones.
  • IoT devices (basic Bluetooth communication).

6. Safety & Notes

  • Use a voltage divider for RX pin if connecting to a 5V Arduino.
  • Keep distance within 10 meters (classic modules).
  • Do not expose to electrical shorts or water.
  • Default HC-05 settings → 9600 baud, PIN: 1234 or 0000.

7. Video Explanation

video coming soon