HC-05 Classic Bluetooth Module

The HC-05 is a popular Classic Bluetooth (v2.0 + EDR) serial communication module that adds two-way wireless connectivity to your projects. It operates using the Serial Port Protocol (SPP) and communicates via UART, making it extremely easy to interface with Arduino, ESP32, STM32, and other microcontrollers. Unlike HC-06 (slave only), the HC-05 can be configured as both Master and Slave using AT commands — allowing microcontroller-to-microcontroller wireless communication as well as smartphone/laptop connectivity. The module operates on 3.3V logic but accepts 5V power supply via onboard regulator, eliminating the need for external level shifting.