Today we discovered the problem we were having with our circuit. The microphone audio jack was not wired to the circuit correctly. The wires were both going to the audio signal pin, so the audio jack was not grounded. To fix this, the ground wire was moved to the ground pin. Once this was done, we started seeing a proper signal on the analog input into the Arduino. This was monitored using the Waveforms software and Analog Discovery. However, the connections to the audio jack pins are loose so the wires will need to be soldered to make sure that loose connections are not causing problems.
We tested the circuit by playing the provided audio file but we believe there was interference from the phone or in the background of the audio because the frequency readings would fluctuate. Our next step is to test our circuit with a live guitar to hopefully minimize interference. Then we are going to write code to output the note being played (determined by the frequency) to a seven segment display.