#define sensorPin A0
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  while(analogRead(sensorPin) > 100 ){
    blink();
    Serial.println(".");
    Serial.println(analogRead(sensorPin));
  }
  Serial.println(analogRead(sensorPin));
}

void blink()
{
  digitalWrite(LED_BUILTIN, HIGH);
  delay(200);
  digitalWrite(LED_BUILTIN, LOW);
  delay(200);
}