The HC-05 Bluetooth Module (CSR Chip) is a versatile and compact wireless communication module designed for seamless integration with microcontrollers like Arduino, Raspberry Pi, and more. Unlike HC-06, the HC-05 supports both Master and Slave modes, making it suitable for a wide range of serial communication applications. It operates on Bluetooth v2.0 + EDR protocol using the reliable GFSK modulation technique for strong and stable data transmission. The module communicates via UART and comes preconfigured with a default baud rate of 9600 bps. Whether you're developing wireless data transfer solutions, remote control systems, or embedded Bluetooth applications, the HC-05 offers dependable performance with a range of up to 10 meters in open space. Featured By RoboticsBD.
Product Images are shown for illustrative purposes only and may differ from the actual product.
The HC Bluetooth module is an older design and may not be compatible with the latest Android or iOS devices. For reliable operation, please use it with an older Android/iOS device, or alternatively use a BLE scanner app to detect and connect to the module.
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Features:
Supports Master and Slave Modes – Highly adaptable for different wireless setups.
Bluetooth v2.0 + EDR Compliance for fast and secure data transmission.
Default UART Baud Rate of 9600 bps, user-configurable via AT commands.
Integrated CSR Bluetooth Chip with high performance and power efficiency.
Low Power Consumption – Matching communication current: 8mA.
Strong Signal Sensitivity with –84dBm at 0.1% BER.
Wireless Range up to 10 Meters in open environments.
Compact PCB Design (43mm x 16.5mm x 7mm) with onboard status LEDs.
Compatible with Arduino, STM32, ESP32, Raspberry Pi, and other MCUs.
Widely Used in IoT, GPS, Industrial Automation, and Robotics Projects.
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Applications:
Embedded Wireless Communication between microcontrollers and mobile devices.
Bluetooth-Enabled Robotics for real-time remote control.
IoT Data Transmission and Monitoring applications.
GPS Receivers and Bluetooth-enabled tracking systems.
Wireless Serial Logging for industrial and consumer electronics.
Bluetooth-Controlled Home Automation like lights, fans, and appliances.
Educational and DIY Electronics Projects involving serial data exchange.
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| General Specifications |
| Model | HC-05 |
| Bluetooth Version | v2.0 + EDR |
| Operating Mode | Master / Slave |
| Frequency | 2.4GHz ISM Band |
| Modulation | GFSK |
| Emission Power | ≤ 4dBm, Class 2 |
| Sensitivity | ≤ -84dBm at 0.1% BER |
| Operating Voltage | 3.6V – 6V DC |
| Operating Current | 30–50mA |
| Communication Interface | UART (TXD, RXD) |
| Default Baud Rate | 9600 bps |
| Operating Range | Up to 10 meters (open space) |
| Communication Speed | Async: 2.1Mbps / 160 kbps; Sync: 1Mbps |
| Security | Authentication and Encryption |
| Operating Temperature | -20°C to +75°C |
| Dimensions (LxWxH) | 43mm x 16.5mm x 7mm |
| Weight | 5g |
| Shipment Weight | 0.01 kg |
| Shipment Dimensions | 5 × 3 × 1 cm |
Please allow 5% measuring deviation due to manual measurement.
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Documentation:
Original CSR Chip vs Clone – What’s the Difference?
One of the easiest ways to spot the difference between an original HC-05 module and a clone lies in the Bluetooth chip size and quality.
The original HC-05 uses a genuine CSR chip, which is slightly larger and provides more reliable Bluetooth communication, better range, and full AT command support.
Clone versions often come with smaller, unbranded chips, even falsely labeled as "CSR". These clones may lack proper protocol support, have limited AT commands, and exhibit unstable or slow connections.
Why Choose the Original HC-05?
Backed by a reliable CSR chipset
Better signal stability and communication range
Compact and easy to integrate into projects
Ideal for Arduino and microcontroller applications
Full support for configuration and firmware upgrades
CSR Chip vs Clone (Chip Differences)
| Feature | CSR Chip (Genuine) | Clone CSR Chip (Chinese or non-genuine) |
| Chipset | Original CSR (Cambridge Silicon Radio) UK chip | Copy or alternative low-cost chipset |
| Stability | High – better signal strength, less dropout | Lower – occasional pairing issues or dropouts |
| AT Command Reliability | Fully supported and well-documented | Sometimes inconsistent AT command behavior |
| Firmware Upgradability | Often upgradeable | Often locked or unreliable firmware |
| Price | Slightly higher | Cheaper |
Summary of Bluetooth Modules available in RoboticsBD
Which Should You Use?
For advanced control (Master/Slave, Arduino to Arduino):
→ HC-05 Genuine CSR Chip
For simple, reliable communication (e.g., Arduino to Android):
→ HC-06 Genuine CSR Chip
For budget or experiments:
→ Clone modules are fine, but test each thoroughly.
Package Includes:
1 x Arduino Bluetooth Module HC-05 - CSR Chip
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