The schematic for Team 4.1’s U-Box seems complicated but is actually fairly straightforward. There is essentially a circuit for the LED and LCD screen, and a second circuit for the servo motor. From the A3BU, 3.3V runs through a 330 Ohm resistor to a red LED and back to ground. A switch completes the loop so that the LED will only light up when the switch is flipped. The other side of the switch runs back to an input pin on the A3BU that just lets the micro-controller know which position the switch is in. This is necessary so that our LCD screen knows when to show the different faces.
Unfortunately, the 3.3V from the A3BU were not enough to power the 5V servo, so a second part of the schematic is designed to run this servo. When the switch is flipped, the A3BU tells an Arduino to run its code, and the Arduino outputs the 5V necessary to turn the servo 35 degrees. The servo will rotate and hit the switch back into the off position, causing the LED to turn back off.