Railroad Crossing Lights

1/*
2 Railroad crossing lights
3by DAVID
4 */
5// constants won't  change. Used here to set a pin number :
6const int ledPinP1 =  9;     // the number  of the LED pin
7const int ledPinP2 =  6;     // the number of the LED pin
8const  int ledPinF =  3;     // the number of the LED pin
9const int switchPin = 2;    //  the number of the switch pin
10int switchState = 0;       // variable for reading  the switch status   
11
12void setup() {
13  
14  pinMode(ledPinP1, OUTPUT);  // initialize the LED pin as an output:
15  pinMode(ledPinP2, OUTPUT);
16  pinMode(ledPinF,  OUTPUT);
17  pinMode(switchPin, INPUT);  // initialize the pushbutton pin as an  input:
18}
19
20void loop() 
21{
22    switchState = digitalRead(switchPin);   // read the state of the 
23                                            //pushbuttonvalue:
24    if (switchState == HIGH)   //if the switch on:
25    {
26        digitalWrite(ledPinF,  LOW);     //white LED off
27        digitalWrite(ledPinP1, HIGH);   //red1 LED  on
28        digitalWrite(ledPinP2, LOW);    //red2 LED off
29        delay(400);                     //wait 400ms
30        digitalWrite(ledPinP1, LOW);    //red1  LED off
31        digitalWrite(ledPinP2, HIGH);   //red2 LED on
32        delay(400);
33    }
34    if(switchState == LOW)              //if the switch off
35    {
36        digitalWrite(ledPinP1, LOW);    //red1 LED off
37        digitalWrite(ledPinP2,  LOW);    //red2 LED off
38        digitalWrite(ledPinF, HIGH);    //white LED on
39        delay(500);                     //wait 500ms
40        digitalWrite(ledPinF,  LOW);     //white LED off
41        delay(500);
42    }
43}
44
45