void setup() {
Serial.begin(9600);
pinMode(2, INPUT); //感应器
pinMode(3, OUTPUT); //红灯1
pinMode(4, OUTPUT); //黄灯1
pinMode(5, OUTPUT); //绿灯1
pinMode(6, OUTPUT); //红灯2
pinMode(7, OUTPUT); //黄灯2
pinMode(8, OUTPUT); //绿灯2

digitalWrite(3, HIGH);
digitalWrite(8, HIGH);
}

void loop(){
  int value = digitalRead(2);
  if(value == HIGH){
    Serial.println("有人经过");
    delay(2000);
    digitalWrite(8, LOW);
    digitalWrite(7, HIGH);
    delay(1000);
    digitalWrite(7, LOW);
    digitalWrite(3, LOW);
    digitalWrite(5, HIGH);
    digitalWrite(6, HIGH);

    delay(3000);
    for(int i = 0; i < 3;i++){
    digitalWrite(5, LOW);
    delay(500);
    digitalWrite(5, HIGH);
    delay(500);
    }
    digitalWrite(5, LOW);
    digitalWrite(4, HIGH);
    delay(1000);
     digitalWrite(6, LOW);
    digitalWrite(4, LOW);
    digitalWrite(8, HIGH);
    digitalWrite(3, HIGH);
    delay(1000);
    digitalWrite(8, HIGH);
  }
  else{
    Serial.println("无人");
  }
  }