Vibration Sensor Circuit Using Arduino Nano​

int led = 3;
int vs = 12; // vibration sensor
void setup() {
  pinMode(led, OUTPUT);
  pinMode(vs, INPUT);
  Serial.begin(9600);
}
void loop() {
  long measurement = vibration();
  delay(50);
  Serial.println(measurement);
  if (measurement > 7000) {
    digitalWrite(led, HIGH);
    delay(2000);
  }
  else {
    digitalWrite(led, LOW);
  }
}
long vibration() {                                                                                                                           
  long measurement = pulseIn (vs, HIGH); //wait for the pin to get HIGH and returns measurement
  return measurement;
}