Traffic Lights

The sequence of traffic signals is red, red and amber together, green, amber, and then back to red.

BeginnerShowcase (no instructions)1 hour16,334

Things used in this project

Hardware components

Arduino UNO

3 mm LED: Red

3 mm LED: Yellow

3 mm LED: Green

Resistor 221 ohm

Resistor 1k ohm

Jumper wires (generic)

MALE TO MALE

SparkFun Pushbutton switch 12mm

Software apps and online services

Arduino IDE

Story

This is a simple Traffic signal project.

The sequence of the traffic signal is red, red and amber (yellow) together, green, amber, and then back to red.

As a bonus, if we hold the button down, the lights will change in sequence by themselves with a delay between each step. I've kept the delay to 1-second, you can change it to 2, 3, 5, etc. seconds.

Steps:

1) First connect the 5v and GND of Arduino UNO to breadboard.

2) Connect the LED's to breadboard. Connect the ground terminal (shorter pin of LED) to ground of UNO. You can either connect all the cathode (ground) separately or you can connect them with each other using single strand wires and then connect a common ground terminal. For anode, connect a 220 ohm resistor with the anodes and then connect them to Arduino.

RED-pin 2

YELLOW-pin 3

GREEN-pin 4

3) Connect the button with 1k ohm resistor and then connect it to ground. Connect the other terminal with pin 5 of Arduino.

4) Now write and upload the code to UNO. The LED's should start to blink. Pressing the button will allow it to jump to the next step. Holding the button continuously will allow the LED to remain in the same state.

Code

Code

//Traffic Lights


//Declaring the LED and button pins and initial state
int redPin = 2;
int yellowPin = 3;
int greenPin = 4;
int buttonPin = 5;
int state = 0;

void setup()
{
  //Declaring the functioning of LED and Button
pinMode(redPin, OUTPUT);  
pinMode(yellowPin, OUTPUT);
pinMode(greenPin, OUTPUT);
pinMode(buttonPin, INPUT);
}

void loop()
{
if (digitalRead(buttonPin))
{
if (state == 0)
{
digitalWrite(redPin,HIGH);
digitalWrite(yellowPin,LOW);
digitalWrite(greenPin,LOW);
state = 1;
}
else if (state == 1)
{
digitalWrite(redPin,HIGH);
digitalWrite(yellowPin,HIGH);
digitalWrite(greenPin,LOW);
state = 2;
}
else if (state == 2)
{
digitalWrite(redPin,LOW);
digitalWrite(yellowPin,LOW);
digitalWrite(greenPin,HIGH);
state = 3;
}
else if (state == 3)
{
digitalWrite(redPin,LOW);
digitalWrite(yellowPin,HIGH);
digitalWrite(greenPin,LOW);
state = 0;
}
delay(1000); //the delay can be changed to 2 seconds,3 seconds,etc.
}
}
void setLights(int red, int yellow,
int green)
{
digitalWrite(redPin, red);
digitalWrite(yellowPin, yellow);
digitalWrite(greenPin, green);
}