Basic soil moisture sensor(arduino)

soil_moisture_buzzer.ino

int sensor_pin = A0;
int buzzer_pin = 2;
int output_value ;

void setup() {
  pinMode(buzzer_pin, OUTPUT);
  tone(buzzer_pin, 3500, 200);
  
  Serial.begin(9600);
  Serial.println("Reading From the Sensor ...");
  delay(2000);
}

void loop() {
  output_value = analogRead(sensor_pin);
  Serial.print("Moisture(raw) : ");
  Serial.print(output_value);
  Serial.println();
  output_value = map(output_value, 1000, 250, 0, 100);
  Serial.print("Moisture : ");
  Serial.print(output_value);
  Serial.println("%");

  if(output_value <= 20){
    // beep beep
    Serial.println("beep beep");
    tone(buzzer_pin, 3500, 200);
    delay(200);
    tone(buzzer_pin, 3500, 200);
    delay(200);  
  }
  
  delay(1000);
}