char dataString[50] = {0};
int a =0;

void setup() {
Serial.begin(9600);              //Starting serial communication
}

void loop() {
  a++;                          // a value increase every loop
  sprintf(dataString,"%02X",a); // convert a value to hexa
  Serial.println(dataString);   // send the data
  delay(1000);                  // give the loop some break
}

import serial
ser = serial.Serial('/dev/ttyUSB1',9600)
s = [0,1]
while True:
    read_serial=ser.readline()
    s = str(int (ser.readline(),16))
    print(s)
    print(read_serial)