// Measure Temperature using NTC Thermistor by Solarduino

// 0- General

int decimalPrecision = 2;

// 1- Temperature Measurement

int ThermistorPin = A1;
float voltageDividerR1 = 10000;
float BValue = 3470;
float R1 = 5000;
float T1 = 298.15;
float R2 ;
float T2 ;

float a ;
float b ;
float c ;
float d ;
float e = 2.718281828 ;

float tempSampleRead = 0;
float tempLastSample = 0;
float tempSampleSum = 0;
float tempSampleCount = 0;
float tempMean ;

// 2 - LCD Display

#include LiquidCrystal LCD(8,9,4,5,6,7);
unsigned long startMillisLCD;
unsigned long currentMillisLCD;
const unsigned long periodLCD = 1000;

void setup()
{
// 0- General

Serial.begin(9600);

// 2 - LCD Display

LCD.begin(16,2);
LCD.setCursor(0,0);
startMillisLCD = millis();

}

void loop()

{

// 1- Temperature Measurement

if(millis() >= tempLastSample + 1)
{
tempSampleRead = analogRead(ThermistorPin);
tempSampleSum = tempSampleSum+tempSampleRead;
tempSampleCount = tempSampleCount+1;
tempLastSample = millis();
}

if(tempSampleCount == 1000)
{
tempMean = tempSampleSum / tempSampleCount;
R2 = (voltageDividerR1*tempMean)/(1023-tempMean);

a = 1/T1;
b = log10(R1/R2);
c = b / log10(e);
d = c / BValue ;
T2 = 1 / (a- d);
Serial.print(T2 - 273.15,decimalPrecision);
Serial.println(" °C");

tempSampleSum = 0;
tempSampleCount = 0;
}

// 2 - LCD Display

currentMillisLCD = millis();
if (currentMillisLCD - startMillisLCD >= periodLCD)
{
LCD.setCursor(0,0);
LCD.print("T=");
LCD.print(T2 - 273.15,decimalPrecision);
LCD.print(char(223));
LCD.print("C ");
LCD.setCursor(0,1);
LCD.print(" ");
startMillisLCD = currentMillisLCD ;
}
}