/* this program is the interpretation routine of standard output protocol 
of TFmini product on Arduino. For details, refer to Product Specifications. 
For Arduino boards with only one serial port like UNO board, the function 
of software visual serial port is to be used. */

// Connections
#define RX 5 // O3 Shield Tinkerkit
#define TX 6 // O4 Shield Tinkerkit
#include <SoftwareSerial.h> //header file of software serial port

//define software serial port name as Serial1 and
//define pin5 as RX
//and pin6 as TX
SoftwareSerial Serial1(RX, TX);

/* For Arduinoboards with multiple serial ports like DUEboard, interpret above two pieces of code and
directly use Serial1 serial port */

int dist;     //actual distance measurements of LiDAR
int strength; //signal strength of LiDAR
int check;    //save check value
int i;
int uart[9];             //save data measured by LiDAR
const int HEADER = 0x59; //frame header of data package

void setup()
{
    Serial.begin(9600);    //set bit rate of serial port connecting Arduino with computer
    Serial1.begin(115200); //set bit rate of serial port connecting LiDAR with Arduino
}

void loop()
{
    if (Serial1.available()) //check if serial port has data input
    {
        if (Serial1.read() == HEADER) //assess data package frame header 0x59
        {
            uart[0] = HEADER;
            if (Serial1.read() == HEADER) //assess data package frame header 0x59
            {
                uart[1] = HEADER;
                for (i = 2; i < 9; i++) //save data in array
                {
                    uart[i] = Serial1.read();
                }
                check = uart[0] + uart[1] + uart[2] + uart[3] + uart[4] + uart[5] + uart[6] + uart[7];
                if (uart[8] == (check & 0xff)) //verify the received data as per protocol
                {
                    dist = uart[2] + uart[3] * 256;     //calculate distance value
                    strength = uart[4] + uart[5] * 256; //calculate signal strength value
                    Serial.print("dist = ");
                    Serial.print(dist); //output measure distance value of LiDAR
                    Serial.print('\t');
                    Serial.print("strength = ");
                    Serial.print(strength); //output signal strength value
                    Serial.print('\n');
                }
            }
        }
    }
}