Arduino cơ bản 2: Lập trình Arduino làm hệ thống đèn giao thông

/*
   Traffic Light
   This code copied from the book Beginning-Arduino.
*/
int carRed = 12; //assign the car lights
int carYellow = 11;
int carGreen = 10;
int button = 9; //button pin
int pedRed = 8; //assign the pedestrian lights
int pedGreen = 7;
int crossTime =5000; //time for pedestrian to cross
unsigned long changeTime;//time since button pressed

void setup() {
      pinMode(carRed, OUTPUT);
      pinMode(carYellow, OUTPUT);
      pinMode(carGreen, OUTPUT);
      pinMode(pedRed, OUTPUT);
    pinMode(pedGreen, OUTPUT);
    pinMode(button, INPUT); 
    digitalWrite(carGreen, HIGH); //turn on the green lights
    digitalWrite(pedRed, HIGH); 
}

void loop() {
    int state = digitalRead(button);
        //check if button is pressed and it is over 5 seconds since last button press
        if(state == HIGH && (millis() - changeTime)> 5000){
               //call the function to change the lights
               changeLights();
        }
}

void changeLights() {
    digitalWrite(carGreen, LOW); //green off
    digitalWrite(carYellow, HIGH); //yellow on
    delay(2000); //wait 2 seconds

    digitalWrite(carYellow, LOW); //yellow off
    digitalWrite(carRed, HIGH); //red on
        delay(1000); //wait 1 second till its safe

    digitalWrite(pedRed, LOW); //ped red off
    digitalWrite(pedGreen, HIGH); //ped green on

    delay(crossTime); //wait for preset time period

    //flash the ped green
        for (int x=0; x<10; x++) {
        digitalWrite(pedGreen, HIGH);
        delay(250);
        digitalWrite(pedGreen, LOW);
        delay(250);
         }
                
    digitalWrite(pedRed, HIGH);//turn ped red on
    delay(500);

    digitalWrite(carRed, LOW); //red off
    digitalWrite(carYellow, HIGH); //yellow on 
    delay(1000);
    digitalWrite(carYellow, LOW); //yellow off
    digitalWrite(carGreen, HIGH); 

    changeTime = millis(); //record the time since last change of lights
    //then return to the main program loop
}

int carRed = 12; //assign the car lights
int carYellow = 11;
int carGreen = 10;
int button = 9; //button pin
int pedRed = 8; //assign the pedestrian lights
int pedGreen = 7;
int crossTime =5000; //time for pedestrian to cross
unsigned long changeTime;//time since button pressed

int crossTime =5000; //thời gian cho người đi bộ qua đường là 5s
unsigned long changeTime;//thời gian kể từ khi nhấn nút

void loop() {
  int state = digitalRead(button);
        //check if button is pressed and it is over 5 seconds since last button press
        if(state == HIGH && (millis() - changeTime)> 5000){
               //call the function to change the lights
               changeLights();
        }
}