I discovered that one sensor was enough to record knock information on a board. This was only clear after plotting serial output from the Arduino. This is great because then no extra parts need to be soldered or hooked up.
I got serial communications between the arduino and the laptop to work. The arduino sends data to the Python script in a loop and the computer receives it without a hitch.
My goal for next week is to determine what kind of hard threshold is necessary to bar fake knocks while allowing real knocks to be input into the system. Additionally I need to tie together the arduino code that senses knocks and the code that sends serial information to the Python.