4 phase traffic light controller. The Arduino runs a code that sends out grey code to the 7400 NAND gates that based on the timing will turn either red on one street and green or yellow on the other. Then the Arduino controls the segment display timer and gives you a countdown for when the lights will change. The switch is simulating if a car is there. With the switch off there isn’t a car waiting for the light so the light doesn’t change and the timer starts over. When the switch is on there is a car there so the lights will change until the switch is turned off and it ends on the red, green 25 second phase
Post time: Aug-04-2017