int red = 10; int yellow = 9; int green = 8; void setup(){ pinMode(red, OUTPUT); pinMode(yellow, OUTPUT); pinMode(green, OUTPUT); digitalWrite(green, HIGH); } void loop(){ changeLights(); delay(15000); // wait for 15 seconds } void changeLights(){ // green off, yellow on for 3 seconds digitalWrite(green, LOW); digitalWrite(yellow, HIGH); delay(3000); // turn off yellow, then turn red on for 5 seconds digitalWrite(yellow, LOW); digitalWrite(red, HIGH); delay(5000); // red and yellow on for 2 seconds (red is already on though) digitalWrite(yellow, HIGH); delay(2000); // turn off red and yellow, then turn on green digitalWrite(yellow, LOW); digitalWrite(red, LOW); digitalWrite(green, HIGH); delay(3000); }