2nd Sensor Data will not begin at zero

Hello Y'all,

I've been working with adding Piezo sensors to Arduino and I've run into some problems. When I have one sensor connected, the sensor reads zero until it is struck. When I attach a second sensor, the second sensor's value is always above zero and it's variable, even when not struck. When I first started it was as high as around 700. I cleaned up my and now it's lower, maybe ranging from 4-7. Is it a code thing or hardware? Help me out.

Arduino Code

int analogPin = A0; // Piezo sensor connected to analog pin 0
int analogPin1 = A1; // Piezo sensor connected to analog pin 1
// outside leads to ground and +5V

int val0 = 0; // variable to store the value read
int val1 = 0;

void setup() {
Serial.begin(9600); // setup serial
}

void loop() {
val0 = analogRead(analogPin); // read the input pin
val1 = analogRead(analogPin1);

Serial.print(val0);
Serial.print(" ");
Serial.print(val1);
Serial.print(" \n ");

delay(100); // delay to avoid overloading the serial port buffer
}

Schematics, please.

In addition to the piezo disk, you need a large value resistor from the analog pin to ground, in both cases. People typically use 1 Megohm resistors.

Here are images of my hardware setup. The top is the 5V power, and the bottom is Ground. I used \1 Megohm resistors from A0 and A1 to Ground.

Use your multimeter to check continuity of connections.