HC-05 Master-Slave Bluetooth Transceiver Module

The HC-05 is a Bluetooth module that offers transparent wireless serial communication. It is a class 2 Bluetooth module that can be configured as either a master or slave device. 

The HC-05 is pre-configured as a slave device, but becomes transparent when paired with a master Bluetooth device, such as a tablet, smart phone, or PC.

 
Here are some specifications for the HC-05:

• Bluetooth protocol: Bluetooth Specification v2.0+EDR
• Frequency: 2.4GHz ISM band
• Modulation: GFSK (Gaussian Frequency Shift Keying)
• Emission power: ≤4dBm, Class 2
• Sensitivity: ≤-84dBm at 0.1% BER
• Speed: Asynchronous: 2.1Mbps(Max) / 160 kbps, Synchronous: 1Mbps/1Mbps

 
The HC-05 has two operating modes:

• Data mode: Can send and receive data from other Bluetooth devices
• AT Command mode: Can change the default device settings

 
The HC-05 is a popular choice for hobbyists and engineers who want to build wireless applications and IoT devices. It is a drop-in replacement for wired serial connections and can be used to establish connections between PCs and MCUs, or embedded projects.