HC-05 6-Pin Bluetooth Module, No Button

The HC-05 Bluetooth module is a 6-pin serial wireless transceiver that adds cable-free UART Bluetooth communication to microcontroller and single-board computer projects, letting Arduino, Raspberry Pi, ESP32, and STM32 systems exchange data with compatible Bluetooth hosts for robotics, home automation, telemetry, remote control, and prototyping. Based on the popular HC-05 platform, it is widely used as a transparent serial link for sending sensor readings, commands, and debug data, and this no-button version suits builds where setup is handled through the module pins and AT command access rather than an onboard key switch.