#include <WiFi.h>
#include <HTTPClient.h>

const int rtdPin = 34; // Analog pin connected to potentiometer we have taken for demonstration where input as a voltage is variable


void setup()   // Beginning of the program
{
  Serial.begin(115200);
}

void loop() {
  // Read analog voltage from the resistor network
  int sensorValue = analogRead(rtdPin);  
  Serial.print("pin value: ");
  Serial.println(sensorValue);


  
  // Convert analog reading to voltage
  float voltage = sensorValue * (3.3 / 4095); // Assuming ESP32 ADC resolution of 12 bits and Vref of 3.3V
  
  // Calculate resistance based on voltage using Ohm's Law
  // Replace R1 and R2 with the values of the resistors in rtd network resistor in series
  float R1 = 0.2; // assume resistance r1 in circuit is 0.2 ohm
  float R2 = 0; // assume r2 having a value of 0 ohm 
  float R_total = (R1 + R2); // Calculate total resistance of the network
  float rtdResistance = (voltage * R_total) / (3.3 - voltage); // Calculate   resistance of RTD sensor
  Serial.print("Resistance of RTD: ");
  Serial.print(rtdResistance);
  // Simulated temperature conversion based on resistance
  // Replace with your own temperature-resistance conversion formula
  float simulatedTemperature = convertToTemperature(rtdResistance);
  
  // Print temperature
  Serial.print("Temperature: ");
  Serial.print(simulatedTemperature);
  Serial.println(" °C");
  delay(1000);
}

 // Function to calculate using liner approximation formula for this simulation only

float convertToTemperature(float resistance) {
  
   // based on the characteristics of your simulated RTD sensor.
  // For simplicity, we'll return a linear approximation here.
  float temperature = resistance * 100; // Linear approximation for demonstration only 
  return temperature;
}