The primary goal of this project is to create an embedded system that detects passing cars and turns on the light to save energy on street lights. The Arduino is simply alerted to turn on the street lights whenever an infrared sensor is spotted. After that, the lights are turned on until the car leaves and then turn off on their own. Another variation on this strategy is to use PWM to keep the lights at a minimum intensity without fully turning them off, then turn them on to their maximum intensity as soon as the system detects a vehicle. However, the circuit in this article is set up so that lights are always turned off and only come on when a vehicle is present.