HC-05 Bluetooth Module (NORMAL QUALITY)

The HC-05 Bluetooth Serial Module is one of the most popular and widely used wireless communication modules in the maker, hobbyist, and engineering communities. Based on the proven Bluetooth Specification v2.0 + EDR (Enhanced Data Rate) standard, it acts as a transparent wireless serial (UART) bridge , allowing any device with a TX/RX serial interface to communicate wirelessly over Bluetooth — essentially turning your Arduino, microcontroller, or computer into a Bluetooth-enabled device. Unlike the simpler HC-06 which only operates as a Slave, the HC-05 module can be configured as either a Master or a Slave , giving it significantly more flexibility. As a Slave, it can pair with smartphones, tablets, PCs, and PDAs to receive commands and send data. As a Master, it can actively search for and connect to other Bluetooth devices, making it ideal for module-to-module wireless communication in robotics and automation projects. The module supports a wide range of baud rates from 9600 up to 115200 bps , ensuring compatibility with most serial communication setups. It operates on a +3.3V DC supply with around 50mA current consumption , but all signal pins are 3V–6V tolerant , allowing direct connection to both 3.3V and 5V microcontrollers like Arduino UNO, Mega, and Nano without requiring an additional level shifter. Important: Do not connect the module directly to a computer's RS232 serial port; you must use a USB-to-TTL converter or an Arduino-based interface. With features like authentication and encryption , the HC-05 ensures secure wireless connections. Its compact dimensions of just 15.2 × 35.7 × 5.6 mm and wide working temperature range of -20°C to +75°C make it suitable for a vast array of applications, including Bluetooth-controlled robots, home automation systems, IoT projects, wireless sensor networks, mobile-controlled devices, data logging, and DIY electronics . It works seamlessly with Arduino, Raspberry Pi, ESP32, STM32, PIC , and most other microcontroller platforms, and can communicate with Android phones, iOS devices, Windows PCs, and Mac computers running a Bluetooth serial terminal app. Specifications Module Name: HC-05 Bluetooth Serial Module Bluetooth Protocol: Bluetooth Specification v2.0 + EDR Operating Frequency: 2.4 GHz ISM Band Modulation: GFSK (Gaussian Frequency Shift Keying) Emission Power: ? 4 dBm (Class 2) Sensitivity: ? -84 dBm at 0.1% BER Asynchronous Speed: 2.1 Mbps (Max) / 160 kbps Synchronous Speed: 1 Mbps / 1 Mbps Supported Baud Rates: 9600, 19200, 38400, 57600, 115200 bps Security: Authentication and Encryption Profiles Supported: Bluetooth Serial Port (SPP) Operating Modes: Master / Slave (configurable) Power Supply: +3.3V DC, 50 mA Signal Pin Tolerance: 3.3V – 6V tolerant Working Temperature: -20°C to +75°C Dimensions: 15.2 × 35.7 × 5.6 mm Default Pairing Code: 1234 or 0000 Connection: 6-pin interface (VCC, GND, TXD, RXD, KEY, STATE) Applications Arduino Bluetooth Projects – wireless control and data transmission Bluetooth-Controlled Robots – control robots via smartphone or PC Home Automation Systems – wirelessly control lights, fans, and appliances Wireless Sensor Networks – transmit sensor data without cables IoT and Smart Devices – add Bluetooth connectivity to embedded systems DIY Mobile-Controlled Devices – build apps to control hardware via Android/iOS Wireless Data Logging – send logged data from microcontrollers to PCs Smart Home Switches – remotely control electrical devices Educational STEM Projects – great for teaching wireless communication PC to Microcontroller Communication – replace USB cables with wireless link Module-to-Module Communication – pair two HC-05s for wireless serial link Remote Monitoring Systems – monitor sensors from a phone or computer