void reading_data () {
  soilmoisturevalue = analogRead(34); // soil moisture reading connected to pin 34, an analog-to-digital converter pin on the esp32  
  Serial.print("soilmoisture");
  Serial.println(soilmoisturevalue);

  String moisture = String(soilmoisturevalue); // for MQTT transmission
  moisture.toCharArray(soilmoisturearray, moisture.length() + 1);

  client.publish(soilmoisture_topic, soilmoisturearray); // the soil moisture values are published under the topic soil moisture

  temperaturevalue = sht31.readTemperature(); // temperature reading obtained by the SHT31 sensor
  humidityvalue = sht31.readHumidity(); // humidity reading obtained by the SHT31 sensor

  if (! isnan(temperaturevalue)) {  // check if 'is not a number', then convert to a char array
    String temperature = String(temperaturevalue);// for MQTT transmission
    temperature.toCharArray(temperaturearray, temperature.length() + 1);
    client.publish(temperature_topic, temperaturearray);// To publish the topic under 

    Serial.print("Temp *C = "); Serial.print(temperature); Serial.print("\t\t"); // gives the temperature in degree celcius
  } else {
    Serial.println("Failed to read temperature");
  }

  if (! isnan(humidityvalue)) {  // check if 'is not a number'
    String humidity = String(humidityvalue);
    humidity.toCharArray(humidityarray, humidity.length() + 1);
    client.publish(humidity_topic, humidityarray); // the humidity values are published under the topic humidity

    Serial.print("Hum. % = "); Serial.println(humidity); // gives the humidity value as a percentage
  } else {
    Serial.println("Failed to read humidity");
}

if (soilmoisturevalue > 2800) {
  digitalWrite (PIN, HIGH); // if soil moisture value is higher than 2800, switch on the water pump
  delay(1000); // The pump is switch on for 1 sec until the moisture level drops below 2800
}
else {
}
digitalWrite (PIN, LOW); //Water pump turned off if soil moisture value is lower than 2800

}