#include "SR04.h"
#define TRIG_PIN 6
#define ECHO_PIN 7

#define LED22 22

int buzzer=8;
SR04 sr04=SR04(ECHO_PIN,TRIG_PIN);//定义对象sr04，初始化引脚


void ZHW(long a){//自定义函数

unsigned char i,j;
while (a<5)
  {
     digitalWrite(LED22,HIGH);//LED灯亮
     delay(1000);
    for(i=0;i<80;i++)//输出一种频率的声音
    {
      digitalWrite(buzzer,HIGH);//发声
      delay(5);
      digitalWrite(buzzer,LOW);//不发声
      delay(5);
    }
    for(i=0;i<100;i++)//输出另一种频率的声音
    {
      digitalWrite(buzzer,HIGH);//发声
      delay(10);
      digitalWrite(buzzer,LOW);//不发声
      delay(10);

    }
    
  }
}
long a;
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
Serial.println("Example written by Coloz From Arduin.CN");
delay(1000);

pinMode(buzzer,OUTPUT);//设置数字引脚为输出模式

pinMode(LED22,OUTPUT);//设置数字引脚为输出模式

}

void loop() {
  // put your main code here, to run repeatedly:
a=sr04.Distance();//读取障碍物和SR04的距离
Serial.print(a);//送串口监视器显示
Serial.println("cm");
delay(1000);
ZHW(a);
}