#include <math.h>


// Define constants
const float BETA = 3950; // Beta coefficient of the thermistor
#define ADC_CHANNEL 0   // ADC channel to which the thermistor is connected

void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Configure the ADC
  ADCSRA |= (1 << ADEN);  // Enable the ADC
  ADCSRA |= (1 << ADPS2) | (1 << ADPS1); // Set prescaler to 64 for ~250kHz ADC clock
  ADMUX = (1 << REFS0);   // Use AVcc as the reference voltage (5V)
}

uint16_t readADC(uint8_t channel) {
  // Select ADC channel (MUX bits in ADMUX register)
  ADMUX = (ADMUX & 0xF0) | (channel & 0x0F);

  // Start the conversion
  ADCSRA |= (1 << ADSC);

  // Wait for the conversion to complete (ADIF flag set)
  while (!(ADCSRA & (1 << ADIF)));

  // Clear the ADIF flag by writing 1 to it
  ADCSRA |= (1 << ADIF);

  // Return the ADC value
  return ADC;
}

void loop() {
  // Read ADC value from channel 0
  uint16_t analogValue = readADC(ADC_CHANNEL);

  // Convert ADC value to temperature in Celsius using the Steinhart-Hart equation
  float resistance = 10000.0 / (1023.0 / analogValue - 1.0); // Assuming 10k fixed resistor
  float celsius = 1.0 / (log(resistance / 10000.0) / BETA + 1.0 / 298.15) - 273.15;

  // Print the temperature
  Serial.print("Temperature: ");
  Serial.print(celsius);
  Serial.println(" ℃");

  // Delay for 1 second
  delay(1000);
}