#define BUZER 2

void setup() {
  Serial.begin(9600)
  pinMode(A5, INPUT);
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(BUZZER, OUTPUT);
}

void ledBlink(int speed) {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(speed);
  digitalWrite(LED_BUILTIN, LOW);
}

void soundAlert(int speed,int freq){
  tone(BUZZER,freq);
  delay(speed);
  noTone(BUZZER);
}

void loop() {
  int sensor_value = analogRead(A5);
  if(sensor_value < 100){
    ledBlink(500);
    soundAlert(500,1000);
  }

}