#include <Arduino.h>

// Pins and constants
#define TRIG_PIN 14  // D5 on ESP8266
#define ECHO_PIN 12  // D6 on ESP8266
const int analogPin = 34; // GPIO 34 for analog input
const float nominalResistance = 10000; // 10k Ohm nominal resistance at 25 degrees C
const float nominalTemperature = 25; // nominal temperature value (in Celsius)
const float bCoefficient = 3950; // Beta coefficient of the thermistor (usually 3000-4000)
const int seriesResistor = 10000; // 10k Ohm series resistor

// Shared variables
volatile long distance;
volatile float temperatureC;

void setup() {
  Serial.begin(115200);

  pinMode(TRIG_PIN, OUTPUT);  
  pinMode(ECHO_PIN, INPUT); 
}

void loop() {
  measureDistance();
  measureTemperature();
  
  // Print distance and temperature values
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  Serial.print("Temperature: ");
  Serial.print(temperatureC);
  Serial.println(" °C");

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

// Function to measure distance
void measureDistance() {
  long duration;
  
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);

  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  duration = pulseIn(ECHO_PIN, HIGH);
  distance = (duration / 2) / 29.1;
}

// Function to measure temperature
void measureTemperature() {
  int analogValue = analogRead(analogPin);
  float resistance = seriesResistor / (4095.0 / analogValue - 1);
  float temperatureK = 1.0 / (1.0 / (nominalTemperature + 273.15) + 1.0 / bCoefficient * log(resistance / nominalResistance));
  temperatureC = temperatureK - 273.15;
}