#include <math.h>

const int SENSOR_PIN = PA5;

// Constants for your connections
const float V_SUPPLY    = 5.0f;     // Sensor powered by 5V
const float V_REF       = 3.3f;     // STM32 ADC reference
const float ADC_STEPS   = 4095.0f;  // 12-bit ADC
const float BETA        = 3950.0f;  // NTC Beta coefficient
const float ROOM_TEMP_K = 298.15f;  // 25 °C in Kelvin

void setup() {
  Serial.begin(115200);
  pinMode(SENSOR_PIN, INPUT_ANALOG);
}

void loop() {
  int adc_val = analogRead(SENSOR_PIN);

  // Convert ADC reading to voltage
  float v_out = ((float)adc_val * V_REF) / ADC_STEPS;

  // Prevent invalid resistance calculation
  if (v_out > 0.05f && v_out < V_SUPPLY) {

    // Calculate thermistor resistance
    float r_ntc = 10000.0f * ((V_SUPPLY / v_out) - 1.0f);

    // Calculate temperature in Celsius
    float tempC = 1.0f /
                  (log(r_ntc / 10000.0f) / BETA +
                   (1.0f / ROOM_TEMP_K))
                  - 273.15f;

    // Convert Celsius to Fahrenheit
    float tempF = (tempC * 9.0f / 5.0f) + 32.0f;

    // Display temperature
    Serial.print("Temperature: ");
    Serial.print(tempC, 1);
    Serial.print(" C  |  ");

    Serial.print(tempF, 1);
    Serial.println(" F");
  }

  delay(1000);
}