/**
  Basic NTC Thermistor demo
  https://wokwi.com/arduino/projects/299330254810382858

  Assumes a 10K@25℃ NTC thermistor connected in series with a 10K resistor.

  Copyright (C) 2021, Uri Shaked
*/

const float BETA = 3950; // should match the Beta Coefficient of the thermistor
#define ntc_pin A0         // Pin,to which the voltage divider is connected
#define vd_power_pin 0        // [12.8.2023: MERACI PRIPRAVOK NTC&LM35: 0 ORIGINAL:2]  5V for the voltage divider
#define nominal_resistance 10000       //Nominal resistance at 25⁰C
#define nominal_temeprature 25   // temperature for nominal resistance (almost always 25⁰ C)
#define samplingrate 5    // Number of samples 
#define beta 3950  // The beta coefficient or the B value of the thermistor (usually 3000-4000) check the datasheet for the accurate value.
#define Rref 10000   //Value of  resistor used for the voltage divider = r2
int samples = 0;   //array to store the samples


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

void loop() {
  float analogValue = analogRead(A0);
  Serial.print("Analog ");
  Serial.println(analogValue);
  uint8_t i;
  samples = 0;
  // take voltage readings from the voltage divider
  digitalWrite(vd_power_pin, HIGH);
  for (i = 0; i < samplingrate; i++) {
    samples += analogRead(ntc_pin);
    delay(10);
  }

  
  float average;
  average = 0;
  average = samples / samplingrate;
  Serial.print("ADC readings: ");
  Serial.println(analogValue);
  float celsius = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  Serial.print("Temperature: ");
  Serial.print(celsius);
  Serial.println(" ℃");

  average = 1023 / average - 1;
  average = Rref / average;
  Serial.print("Thermistor resistance ");
  Serial.println(average);
  delay(1000);

  float rNTC = Rref/(1023/analogValue-1);
  Serial.print("rNTC:");
  Serial.println(rNTC);
  delay(1000);

 // Vout = Vin*[R2/(R1+R2)] (3)
 // R2,rNTC=(Vout*R1) / (Vin-Vout)

    //Vout = (a0 *Vin)/1024
   // R2=(Vout*R1) / (Vin-Vout) 
   
   float voltage = analogValue *(5.0/1023.0);
   float vout =(analogValue*voltage)/1024;
   //float rNTC1 =(vout*Rref) / (voltage-vout) ; 
  float rNTC1 =(((analogValue*voltage)/1024)*Rref) / ((analogValue *(5.0/1023.0))-((analogValue*voltage)/1024)) ;
   Serial.print("voltage: ");
   Serial.println(voltage);
   Serial.print("rNTC1: ");
   Serial.println(rNTC1);

}