基本的蓝牙 Hello World

#include <SoftwareSerial.h>
// its always better to change the default tx and rx as the may interfere with other process in future.
 
// configure tx , rx by defualt they will be 0 and 1 in arduino UNO  
SoftwareSerial blue(3,2); 
void setup() {
  // preferred baud rate/data transfer rate in general is 38400
     blue.begin(38400);
  // do initialization or put one time executing code here
}

void loop() {

  // put code that you want it to run every time no matter what
    if(blue.available()){
        // put only that code which needsd to run when there is some data
        // This means that the their is some data sent over the bluetooth
        // You can do something with the data

        int n;
        // consider that the data received to be integer, read it by using blue.parseInt();

        n = blue.parseInt();

    }

}