Piezoelectric film sensor to capture vibrating shoelace waveform

Hi all,

I just started playing with electronics and arduino in general, and did a lot of research into what Im about to ask, but am not sure if my understanding is correct. Please forgive me if it might misinformed.

I’m using a tightened shoelace (tied tight end to end and yes it has to be a shoelace) with a piezo film sensor taped on it. Now what I want to do is capture a set of amplitude and frequency data that resembles a wave form in order to place a prerecorded audio on my computer with the same amplitude and frequency (did this with Max MSP).

The program is super simple cause all I need is to print the data to serial so I can manipulate it in Max MSP:

void setup() {
  Serial.begin(115200);
} 
 
void loop() {
int sensorState = analogRead(0);
 Serial.println(sensorState);
}

However the waveform is not periodic, and looks highly irregular.

Anyways, could this be because either the piezo film sensor isn’t sensitive enough, the arduino’s sampling rate is not fast enough or the shoelace just isnt stiff enough (though the shoelace is really tight already like a guitar string)?

Attached is a picture of my setup (the whatsapp image) and a picture of whats being received in the serial plotter. the setup is just a piezo sensor with a 12k resistor connected on the ground side.

Any ideas, new or old, improvements, suggestions are welcome!

Thank you!