In this very very basic project, this switch reveals if a seat is available or occupied, using similar lighting signals to a taxi. When the seat is free, the switch is not activated and the light remains on and blinking. When someone sits down, the switch is activated, turning the switch off. The code I used for this is the same one that we used in class. The photo shows the Arduino set up but does not include the switch (I left that at home). The red and black wires are connected to the switch when it is attached.