// variables int GREEN = 2; int YELLOW = 3; int RED = 4; int DELAY_GREEN = 5000; int DELAY_YELLOW = 2000; int DELAY_RED = 5000; // basic functions void setup() { pinMode(GREEN, OUTPUT); pinMode(YELLOW, OUTPUT); pinMode(RED, OUTPUT); } void loop() { green_light(); delay(DELAY_GREEN); yellow_light(); delay(DELAY_YELLOW); red_light(); delay(DELAY_RED); } void green_light() { digitalWrite(GREEN, HIGH); digitalWrite(YELLOW, LOW); digitalWrite(RED, LOW); } void yellow_light() { digitalWrite(GREEN, LOW); digitalWrite(YELLOW, HIGH); digitalWrite(RED, LOW); } void red_light() { digitalWrite(GREEN, LOW); digitalWrite(YELLOW, LOW); digitalWrite(RED, HIGH); }