HC-05 Bluetooth module Set in AT command mode

HC-05 embedded Bluetooth serial communication module (can be short for module) has two work modes: order-response work mode and automatic connection work mode. And there are three work roles (Master, Slave and Loopback)

at the automatic connection work mode. When the module is at the automatic connection work mode, it will follow the default way set lastly to transmit the data automatically. When the module is at the order-response work mode, user can send the AT command to the module to set the control parameters and sent control order.

Specifications: 

• TTL data transparent transfer between a host Bluetooth device. 
• Works with any USB Bluetooth adapters. 
• Default Baud Rate: 9600,8,1,n. 
• Coverage up to 30ft. 
• Built in antenna. 
• Power input: 3.6-5.5V 
• Mini Size.
• Dimensions: 1.73 in x 0.63 in x 0.28 in (4.4 cm x 1.6 cm x 0.7 cm)
• Weight: 0.25 oz (7 g)

     Hardware Setup for  HC-05 module in AT command mode  is shown below

 HC-05          TTL to USB conveter
 
  TX-------------RX
  RX---------TX(Though it works fine for me without voltage divider , i recommend a voltage divider)
  VCC-----------5V
  GND----------GND
  E/WAKEUP----3.3V


  Connect USB To TTL converter to your computer , open hyperterminal select com port and set baudrate. Now test AT commands!!.

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