Keywish Hummer-Bot, Инструкция по эксплуатации

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Fig.3.2.47 HC-05 Module
3.2.7.2 Bluetooth protocol
Using Bluetooth to control the car means we use the Android app to control the Bluetooth sending
instructions to the Arduino serial port, so as to control the motor's forwarding, reversing, speed and so on.
Since the wireless communication is involved, one of the essential issues is the communication problem
between the two terminals. But there is no common "language" between them, so designing communication
protocols are required to ensure a perfect interaction between Android and Arduino. The main process is: the
Android identification terminal packs the detected commands into the corresponding data packets, and then
sends them to the Bluetooth module (HC-05). When HC-05 receives the packets, it will transmit them to
Arduino through the serial port, then Arduino to analyze the data packets and execute the corresponding
actions. The data format sent by the upper computer end (Android) is as follows, which mainly contains 6
fields, we use a structure to represent it
Start_code Length Type Data Checksum Tail
The start_code is the beginning part of the packet, for example, the unification is designated as 0xAA.
The type represents the type of the slave device.
The addr is the address of the controlling device.
The function means the functional types of device which need to control, we are currently supporting the
following functional types
typedef struct
{
unsigned char start_code ; // 8bit 0xAA
unsigned char type ;
unsigned char addr ;
unsigned short int function ; // 16 bit
unsigned char * data ; // n bit
unsigned short int sum ; // check sum
unsigned char end_code ; // 8bit 0x55
} ST_protocol ;