How is it possible that my skin temperature is so constant? Here's the code

#include &lt;OneWire.h&gt; 

int DS18S20_Pin = 3; //DS18S20 Signal pin on digital 3
unsigned long startTime = 0;
#define MEASURE_PERIOD 250
//Temperature chip i/o
OneWire ds(DS18S20_Pin);  // on digital pin 3

void setup() {
  Serial.begin(115200);
}

void loop() {
  if((millis() - startTime) &gt;= MEASURE_PERIOD)
    {
        startTime += MEASURE_PERIOD;
        float temperature = getTemp();
        Serial.println(temperature);
    } //just here to slow down the output so it is easier to read

}


float getTemp(){
  //returns the temperature from one DS18S20 in DEG Celsius

  byte data[12];
  byte addr[8];

  if ( !ds.search(addr)) {
      //no more sensors on chain, reset search
      ds.reset_search();
      return -1000;
  }

  if ( OneWire::crc8( addr, 7) != addr[7]) {
      Serial.println("CRC is not valid!");
      return -1000;
  }

  if ( addr[0] != 0x10 &amp;&amp; addr[0] != 0x28) {
      Serial.print("Device is not recognized");
      return -1000;
  }

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

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


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

  ds.reset_search();

  //byte MSB = data[1];
 // byte LSB = data[0];

  float tempRead = ((((int)data[1]) &lt;&lt; 8) | data[0]); //using two's compliment
  float TemperatureSum = tempRead / 16;

  return TemperatureSum;

}
Examine your code closely.  It appears that you are partially implementing extended resolution calculations in this line of code:

  float TemperatureSum = tempRead / 16;


In the DS18S20 specifications the extended resolution equation used is:

 TEMPERATURE = TEMP_READ * 0.25 - ((COUNT_PER_C - COUNT_REMAIN) / (COUNT_PER_C))


Where COUNT_PER_C is a DS18S20 register containing a value of up to 16.  Maybe that is where 16 originated?

I believe what you want to do is divide the recovered value by 2.0 base on table 1 from the DS18S20 specifications:

  float TemperatureSum = tempRead / 2.0;


Don't forget the "." in case the compiler you are using decides to do integer math dripping the "float" part before assigning it to TemperatureSum.