// include the library for the temperature sensor
#include <OneWire.h>
#include <DallasTemperature.h>

// set up the pin for the temperature sensor
#define ONE_WIRE_BUS 2

// create an instance of the OneWire and DallasTemperature libraries
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

// set up the pin for the fan
int fanPin = 3;

void setup() {
  // start serial communication
  Serial.begin(9600);

  // start the temperature sensor
  sensors.begin();
  
  // set the fan pin to output mode
  pinMode(fanPin, OUTPUT);
}

void loop() {
  // call the sensors.requestTemperatures() function to get the temperature reading
  sensors.requestTemperatures();

  // get the temperature reading in degrees Celsius
  float temperatureC = sensors.getTempCByIndex(0);

  // print the temperature reading to the serial monitor
  Serial.print("Temperature: ");
  Serial.print(temperatureC);
  Serial.println(" C");

  // check if the temperature is above 90 degrees Celsius
  if (temperatureC >= 90) {
    // turn on the fan
    digitalWrite(fanPin, HIGH);
  }

  // check if the temperature is below 70 degrees Celsius
  else if (temperatureC <= 70) {
    // turn off the fan
    digitalWrite(fanPin, LOW);
  }

  // wait for 1 second before checking the temperature again
  delay(1000);
}