红绿灯

//项目三 -- 互动交通信号灯int carRed = 12; //设置汽车灯int carYellow = 11;int carGreen = 10;int button = 9; //按钮引脚int pedRed = 8; //设置行人灯int pedGreen = 7;int crossTime =5000;//允许行人通过的时间unsigned long changeTime;//按钮按下后的时间void setup() {        //所有LED设置为输出模式  pinMode(carRed, OUTPUT);  pinMode(carYellow, OUTPUT);  pinMode(carGreen, OUTPUT);  pinMode(pedRed, OUTPUT);        pinMode(pedGreen, OUTPUT);        pinMode(button, INPUT); //按钮设置为输入模式        digitalWrite(carGreen, HIGH); //车行digitalWrite(pedRed, LOW);  //人停}void loop() {int state = digitalRead(button);        //检测按钮是否被按下，并且是否距上次按下后有5秒的等待时间        if(state == HIGH && (millis() - changeTime)> 5000){               //调用变灯函数               changeLights();        }}void changeLights() {digitalWrite(carGreen, LOW); //汽车绿灯灭digitalWrite(carYellow, HIGH); //汽车黄灯亮delay(2000); //等待2秒digitalWrite(carYellow, LOW); //汽车黄灯灭digitalWrite(carRed, HIGH); //汽车红灯亮        delay(1000); //为安全考虑等待1秒digitalWrite(pedRed, LOW); //行人红灯灭digitalWrite(pedGreen, HIGH); //行人绿灯亮delay(crossTime); //等待一个通过时间//闪烁行人灯绿灯，提示可过马路时间快到        for (int x=0; x<10; x++) {        digitalWrite(pedGreen, HIGH);delay(250);digitalWrite(pedGreen, LOW);delay(250);         }         digitalWrite(pedRed, HIGH);//行人红灯亮delay(500);digitalWrite(carRed, LOW); //汽车红灯灭digitalWrite(carYellow, HIGH); //汽车黄灯亮delay(1000);digitalWrite(carYellow, LOW); //汽车黄灯灭        digitalWrite(carGreen, HIGH); //汽车绿灯亮changeTime = millis(); //记录自上一次灯变化的时间//返回到主函数循环中}