Pressure Switch:
Now that you have your compressor properly wired and tested, let's try to control it using the pressure switch. This part is easy, and should not take more than a few minutes to complete.
First, get a PWM cable (if you have one with broken pins on the male end, then great!), two small gauge (Red) ring terminals, and your pressure switch.
Next, cut off the male end. You can discard it or save it as you wish. Strip back the wire and attach the ring terminals to the white and black wires. The red wire will remain unwired, and you are encouraged to trim it off. Hook one ring terminal to one side of the pressure switch, and the other ring terminal to the other side. Then plug it into Digital I/O 1. You may pick another port if you're team is confident in programming.
Refer to the PDF below for an image representation:
Pressure Switch.pdf