The Core module is HC-05 Bluetooth 2.0 module. By using this Bluetooth module, you can quickly add Bluetooth features to your Arduino project. The factory setting is slave mode, but you can set this module to master mode so that you might be able to connect to other Bluetooth 2.0 devices. Please note: This is a classic Bluetooth 2.0 module, it is not compatible with iPhone or iPad If you need to use iPhone or iPad to control your Arduino project. You may need a Bluetooth 4.0 BLE module (such as SH-HC-08 Bluetooth 4.0 BLE module)
Bluetooth module HC-05 Master and slave Two in one module
Use the CSR BC417 mainstream Bluetooth chip, Bluetooth V2.0 SPP protocol standards
Module working voltage 3.6 V to 6V
Default rate of 9600,default pin:1234, the user can be set up. Click the button into AT MODE
Can be switched via AT commands as master or slave mode, the device can be connected via AT commands specified.