Saturday, July 30, 2011

Pedestrian Interactive Traffic Light using Arduino UNO

This is a pedestrian interactive traffic light made using Arduino UNO. This is project 4 from the manual that can be found at this link.

Photo of circuit:


The code is as follows:

int carRed = 12;
int carYellow = 11;
int carGreen = 10;
int pedRed = 9;
int pedGreen = 8;
int button = 2;
int crossTime = 5000;
unsigned long changeTime;

int x;

void setup(){
  pinMode(carRed, OUTPUT);
  pinMode(carYellow, OUTPUT);
  pinMode(carGreen, OUTPUT);
  pinMode(pedRed, OUTPUT);
  pinMode(pedGreen, OUTPUT);
  pinMode(button, INPUT);
  digitalWrite(carGreen, HIGH);
  digitalWrite(pedRed, HIGH);


void loop(){
  int state = digitalRead(button);
  if (state == HIGH && (millis() - changeTime) > 5000){
void changeLights(){

  digitalWrite(carGreen, LOW);
  digitalWrite(carYellow, HIGH);
  digitalWrite(carYellow, LOW);
  digitalWrite(carRed, HIGH);
  digitalWrite(pedRed, LOW);
  digitalWrite(pedGreen, HIGH);
  for(int x=0; x<10; x++){
    digitalWrite(pedGreen, HIGH);
    digitalWrite(pedGreen, LOW);

  digitalWrite(pedRed, HIGH);
  digitalWrite(carYellow, HIGH);
  digitalWrite(carRed, LOW);
  digitalWrite(carGreen, HIGH);
  digitalWrite(carYellow, LOW);
  changeTime = millis();


In human language, the following describes what the traffic light was doing:

1. Traffic light waits for user input. The time since the circuit was turned on was continuously logged.
2. If button is pushed, and the last light change was more than 5 seconds ago (determined by subtracting the time recorded at end of last light change and time since circuit was turned on), the yellow light turns on for 2 seconds.
3. Then the red light turns on.
4. After 1 second, the green light for pedestrian turns on for 10 seconds.
5. Pedestrian green light starts blinking 10 times after that.
6. Pedestrian red light turns on.
7. After 0.5 seconds, yellow lights for cars turn on for 1 second.
8. Yellow and red lights for cars turn off, and green light turns on.
9. Traffic light listens for user input. Time since circuit was turned on was recorded at this point.

1 comment:

Anonymous said...

materials list?