In this project we will use all four LEDs to blink a chase pattern. This example shows a very simple way to create a pattern using digitalWrites and delays.
Project Code:
/////////////////////////////////////////////////
// Project 1.02 LED Chase
byte LED1 = 13;
byte LED2 = 6;
byte LED3 = 7;
byte LED4 = 8;
void setup() {
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
pinMode(LED4, OUTPUT);
}
void loop() {
digitalWrite(LED4, LOW);
digitalWrite(LED1, HIGH);
delay(250);
digitalWrite(LED1, LOW);
digitalWrite(LED2, HIGH);
delay(250);
digitalWrite(LED2, LOW);
digitalWrite(LED3, HIGH);
delay(250);
digitalWrite(LED3, LOW);
digitalWrite(LED4, HIGH);
delay(250);
}
/////////////////////////////////////////////////
*If you’re copying and pasting the code, or typing from scratch, delete everything out of a new Arduino sketch and paste / type in the above text.
Here we set the four variables needed to represent the pins that the LEDs are attached to:
byte LED1 = 13;
byte LED2 = 6;
byte LED3 = 7;
byte LED4 = 8;
Next, we need to tell the microcontroller that these pins are outputs:
void setup() {
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
pinMode(LED4, OUTPUT);
}
After that, we can sequentially turn on and off the LEDs to represent a chase pattern. To do this, we have to turn the last LED off, the next LED on, and then wait.
void loop() {
digitalWrite(LED4, LOW);
digitalWrite(LED1, HIGH);
delay(250);
digitalWrite(LED1, LOW);
digitalWrite(LED2, HIGH);
delay(250);
digitalWrite(LED2, LOW);
digitalWrite(LED3, HIGH);
delay(250);
digitalWrite(LED3, LOW);
digitalWrite(LED4, HIGH);
delay(250);
}
What you may have noticed about the code above is that something happened over and over again. Usually, when things happen over and over again, it is a sign that it should be in some kind of loop and/or function.