HC-05D Bluetooth Serial Module

Bluetooth module, is a kind of integrated bluetooth function PCBA board, used for short distance wireless communication according to the function is divided into bluetooth data module and bluetooth voice module. Bluetooth module refers to the integration of Bluetooth functionality of the chip's basic circuitry collection, used for wireless network communications, can be broadly divided into three main types: data transmission module, Bluetooth audio module, Bluetooth audio + data two-in-one module and so on. The general module has the property of semi-finished products, which are over-processed on the basis of chips to

Module size
37*15.6mm, without pins.
Pins
KEY, VCC, GND, RXD, TXD, STATE, STATE is the Bluetooth status pin, outputs low level when not connected, outputs high level when connected, KEY is the AT command setup pin, the same function as the key.
Key
Pressing key is equivalent to pulling pin 34 high/low, which is used in conjunction with AT command. (Most of the AT instructions need to be sent by pressing the key to be effective.)
Voltage Description
Input voltage is 3.2~6V, power supply comes with anti-reverse connection, but reverse connection does not work.
Status indication
Fast flash when the master has not recorded the slave address; slow flash when the slave address is recorded; fast flash when the slave is not connected. After connecting, both master and slave are LED two flash and stop.
Interface Description
Interface level of 3.2 ~ 6V, can be connected to a variety of microcontrollers (Arduino, 51, AVR, PIC, ARM, MSP430, etc.), 5V microcontroller can be directly connected. Directly connected to the serial port of the microcontroller, can not go through the MAX232 chip.
Communication distance
The effective distance is 10 metres in an open environment, more than 10 metres is possible but the quality of communication cannot be guaranteed.