Introduction: Basic Arduino Traffic Light Utilizing Interrupts

The goal of this project is to create a traffic light simulator that reacts to input of a car present at cross road (button).

Required Materials:

- Arduino Uno

- Bread Board

- Bread knife

- Just kidding :)

-Button (Momentary Press)

- LEDs (2 red, 2 yellow, 2 green)

- Resistors (220 ohm(6), 1 Mohm(1))

- 10 or more wires

Step 1: Single LED Connection

- Add a single red LED to the breadboard

- Connect (+) leg of LED to pin 8 on Arduino

- Connect (-) leg on LED to 220 ohm resistor to Ground on breadboard

Step 2: Connect Yellow and Green LEDs

Connect Yellow and Green LEDs as in the previous step

- Yellow to pin 9

- Green to pin 10

Step 3: Connect LEDs for Second Traffic Light Group

Connect the second set of LEDs as the previous steps

- Red to pin 11

- Yellow to pin 12

- Green to pin 13

Step 4: Connect Button

Add button to center of breadboard

- Connect bottom left with 1 Mohm resistor to ground

- Connect bottom right to power rail on breadboard

- Connect top left to pin 2 on Arduino

*pin 2 or 3 are required for interrupts on Arduino UNO

Step 5: Finish Circuit

Connect 5v and Ground from breadboard rails to Arduino

Step 6: Code

Upload code using Arduino IDE

Code Operation:

- Normal Loop

- Alternates Green lights between light one and light two

- The Yellow light and time delays provide a transition between the green lights

- Interrupt (button)

- If the current loop has light two at red then transition light one to red and light two to green

- return to normal loop