Raspberry Pi PWM HAT with modification 

16-channel PWM/Servo HAT with modification (right side). Across the bottom are the 16 sets of 3-pins, each to control a servo, which will change the aspect of a semaphore signal. On the right edge 17 GPIO pins are brought out to control 12 LEDs for the "Parking Lot" signals, 4 LEDs for traffic monitoring and 1 pin for the fan control push button. On top are the 40 pins interconnecting the Pi underneath and the bonnets on top. Power plugs to drive the servos are on the right.