The file that is currently on an Arduino Uno with a serial number of CC2B9309F0DG6LL0

temp_rh.ino

#include <OneWire.h>
#define ZeroPercentVoltage 0.8;

float val = 0;
float RH = 0;
float my_room_temperature = 20; //in degrees C !
float max_voltage = 3.27;

OneWire  ds(2);      // Sensor DS18b20 on pin 2

void setup (void)
{
  Serial.begin(9600);
}

void loop(void)
{
  val = analogRead(A0);
  delay(500);
  //Serial.println(val);
  //my_room_temperature = 20; // If you have temperature reading, put it here (centigrade!)
  max_voltage = (3.27-(0.006706*my_room_temperature)) ; // The max voltage value drops down 0.006705882 for each degree C over 0C. The voltage at 0C is 3.27 (corrected for zero precent voltage)
  float subval = ((val/1023)*5)-ZeroPercentVoltage;
  RH = (subval/max_voltage)*100;
  Serial.print("RH:");
  Serial.println(RH);

  byte i;
  byte present = 0;
  byte type_s;
  byte data[12];
  byte addr[8];
  float celsius;

  if ( !ds.search(addr))   
    //search for next object on Onewire bus. For the first found, continue loop, if none found, restart from 0
  {
    ds.reset_search();
    delay(250);
    return;
  }

  if (OneWire::crc8(addr, 7) != addr[7]) //Check if there is no errors on transmission
  {
    Serial.println("CRC invalide...");
    return;
  }

  if(addr[0] == 0x10)      //Check if it's a DS18b20 on the bus or not
  {
    type_s = 1;
  } else type_s=0;

  ds.reset();
  ds.select(addr);
  ds.write(0x44,1);         // start conversion, with parasite power on at the end

  delay(1000);     

  present = ds.reset();
  ds.select(addr);   
  ds.write(0xBE);         // Read Scratchpad

  for ( i = 0; i < 9; i++)
  {           // we need 9 bytes
    data[i] = ds.read();
  }

  // convert the data to actual temperature

  unsigned int raw = (data[1] << 8) | data[0];
  if (type_s)
  {
    raw = raw << 3; // 9 bit resolution default
    if (data[7] == 0x10)
    {
      // count remain gives full 12 bit resolution
      raw = (raw & 0xFFF0) + 12 - data[6];
    }
  }
  else
  {
    byte cfg = (data[4] & 0x60);
    if (cfg == 0x00) raw = raw << 3;  // 9 bit resolution, 93.75 ms
    else if (cfg == 0x20) raw = raw << 2; // 10 bit res, 187.5 ms
    else if (cfg == 0x40) raw = raw << 1; // 11 bit res, 375 ms
  }
  
  celsius = (float)raw / 16.0;
  my_room_temperature = celsius;
  Serial.print("TEMP:");
  Serial.println(celsius);
}