This was one of the first programs i wrote for the arduino after having it a few days :)

we will be making l.e.d police lights with minimal materials

Step 1: You Will Need.

You will need

Arduino (or suitable clone)
Breadboard
2x 240ohm resistors
1x Clear Red l.e.d
1x Clear Blue l.e.d
Some Jumper Cables

Step 2: Place Components Onto Breadboard

Place the components onto the breadboard as the diagram shows

Step 3: Writing the Code.

The code for this project is very, very basic

// Project 1 - Police Lights by Dave1324

int ledDelay = 50; // delay by 50ms
int redPin = 9;
int bluePin = 11;

void setup() {
pinMode(redPin, OUTPUT);
pinMode(bluePin, OUTPUT);

}

void loop() {

digitalWrite(redPin, HIGH); // turn the red light on
delay(ledDelay); // wait 50 ms

digitalWrite(redPin, LOW); // turn the red light off
delay(ledDelay); // wait 50 ms

digitalWrite(redPin, HIGH); // turn the red light on
delay(ledDelay); // wait 50 ms

digitalWrite(redPin, LOW); // turn the red light off
delay(ledDelay); // wait 50 ms

digitalWrite(redPin, HIGH); // turn the red light on
delay(ledDelay); // wait 50 ms

digitalWrite(redPin, :LOW); // turn the red light off
delay(ledDelay); // wait 50 ms

delay(100); // delay midpoint by 100ms

digitalWrite(bluePin, HIGH); // turn the blue light on
delay(ledDelay); // wait 50 ms

digitalWrite(bluePin, LOW); // turn the blue light off
delay(ledDelay); // wait 50 ms

digitalWrite(bluePin, HIGH); // turn the blue light on
delay(ledDelay); // wait 50 ms

digitalWrite(bluePin, LOW); // turn the blue light off
delay(ledDelay); // wait 50 ms

digitalWrite(bluePin, HIGH); // turn the blue light on
delay(ledDelay); // wait 50 ms

digitalWrite(bluePin, LOW); // turn the blue light off
delay(ledDelay); // wait 50 ms

}

Now upload to your arduino and thats it ! :)

Step 4: Experiment

Now you can experiment with the code

for example:

can you alter the code to power 2 more l.e.d's?

can you alter the code to make the lights flash faster?

Good luck!