// Thermistor readout to serial code: thermistor.ino
#include "pins_EINSY_RAMBO.h" // Include the pin definitions for the Einsy Rambo board, sourced from the Marlin firmware

// For a 100k NTC thermistor with 4.7k pull-up resistor:
const float CELSIUS_TO_KELVIN = 273.15; // Absolute zero in Celsius
const float PULLUP_RES = 4700;          // the value of the resistor in series with the thermistor (usually 4.7k)
const float V_REF = 5.0;             // Reference voltage for the ADC (usually 5V)

// For Beta thermistor calculations from Marlin:
const float MARLIN_NOMINAL_RES = 100000; // Resistance at 25 degrees C
const float MARLIN_NOMINAL_TEMP_C = 25;  // Nominal temperature in Celsius
const float MARLIN_BETA_K = 4092;        // The beta coefficient of the thermistor from Marlin

// For Beta thermistor calculation using my own values:
const float NOMINAL_RES = 98000; // Resistance at 25 degrees C
const float NOMINAL_TEMP_C = 25; // Nominal temperature in Celsius
const float BETA_K = 3950;       // The beta coefficient of the thermistor

// For Steinhart-Hart calculations:
const float A = 0.0006608622952;     // Coefficient A for Steinhart-Hart equation
const float B = 0.0002266935852;     // Coefficient B for Steinhart-Hart equation
const float C = 0.00000005819722188; // Coefficient C for Steinhart-Hart equation

void setup()
{
    Serial.begin(115200); // Start the serial communication at 115200 baud rate
    Serial.println("Thermistor Test");
    pinMode(TEMP_0_PIN, INPUT); // Set the thermistor pin as input
}

void loop()
{
    // Read the thermistor value from the analog pin
    int voltage = analogRead(TEMP_0_PIN);                                        // Read the voltage from the thermistor
    float measuredVoltage = voltage * V_REF / 1023.0;                              // Convert ADC reading to actual voltage
    float resistance = (PULLUP_RES * measuredVoltage) / (V_REF - measuredVoltage); // Calculate the resistance of the thermistor

    // Calculate the temperature using the Steinhart-Hart equation
    float steinhart = 1.0 / (A +
                             B * log(resistance) +
                             C * pow(log(resistance), 3));
    steinhart -= CELSIUS_TO_KELVIN; // Convert to Celsius
    Serial.print("Temperature from SH-H (C): ");
    Serial.println(steinhart);

    // Calculate the temperature using the Beta equations
    float tempK = 1.0 / (1.0 / (NOMINAL_TEMP_C + CELSIUS_TO_KELVIN) +
                         (1.0 / BETA_K) * log(resistance / NOMINAL_RES));
    tempK -= CELSIUS_TO_KELVIN; // Convert to Celsius
    Serial.print("Temperature from Beta (C): ");
    Serial.println(tempK);

    // Calculate the temperature using the Marlin beta equations
    float tempKMarlin = 1.0 / (1.0 / (MARLIN_NOMINAL_TEMP_C + CELSIUS_TO_KELVIN) +
                               (1.0 / MARLIN_BETA_K) * log(resistance / MARLIN_NOMINAL_RES));
    tempKMarlin -= CELSIUS_TO_KELVIN; // Convert to Celsius
    Serial.print("Temperature from Marlin Beta (C): ");
    Serial.println(tempKMarlin);

    delay(1000);
}