====== Thermistor ======
====== Temperature Measurement Using Thermistor ======

This scenario demonstrates how to measure temperature using a thermistor (temperature-sensitive resistor) connected to an Arduino Uno. The temperature is calculated using the Steinhart-Hart equation.

===== Prerequisites =====
  * Familiarize yourself with Arduino hardware reference.
  * Basic understanding of analog sensor readings and voltage dividers.
  * Install LiquidCrystal library for LCD display.

===== Hardware Connections =====
| Component  | Arduino Pin |
|------------|-------------|
| Thermistor | A5 (Analog) |
| LCD        | RS=8, EN=9, D4=4, D5=5, D6=6, D7=7 |

===== Suggested Knowledge Resources =====
  * Arduino programming fundamentals
  * [[taltech:arduino:hardware|Arduino Uno Hardware Reference]]

===== Task =====
Measure temperature using a thermistor and display the results (ADC reading, voltage, resistance, and temperature in Celsius) on the LCD.

===== Steps =====

=== Step 1: Include Libraries ===
<code c>
#include <math.h>
#include <LiquidCrystal.h>
</code>

=== Step 2: Initialize LCD ===
Declare LCD pins and initialize:
<code c>
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
const int sensorPin = A5;
</code>

=== Step 3: Setup ===
Set LCD dimensions and initial message:
<code c>
void setup() {
  lcd.begin(16, 2);
  lcd.print("Temperature");
  delay(1000);
}
</code>

=== Step 4: Main Loop ===
Read sensor value, calculate temperature, and display on LCD:
<code c>
void loop() {
  readThermistor(analogRead(sensorPin));
  delay(1000);
  lcd.clear();
}

void readThermistor(int RawADC) {
  double Temp;
  long Resistance;

  // Calculate resistance
  Resistance = ((10240000 / RawADC) - 10000);

  // Display ADC and voltage
  lcd.setCursor(0, 0);
  lcd.print("AD=");
  lcd.print(RawADC);
  lcd.setCursor(8, 0);
  lcd.print("U=");
  lcd.print(((RawADC * 5.0) / 1024.0), 3);

  // Display resistance
  lcd.setCursor(0, 1);
  lcd.print("R=");
  lcd.print(Resistance);

  // Calculate temperature (Steinhart-Hart)
  Temp = log(Resistance);
  Temp = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * Temp * Temp)) * Temp);
  Temp = Temp - 273.15; // Convert Kelvin to Celsius

  // Display temperature
  lcd.setCursor(8, 1);
  lcd.print("T=");
  lcd.print(Temp);
}
</code>

===== Validation =====
LCD displays accurate ADC values, voltage readings, resistance, and temperature in Celsius. Typical room temperature should range between 19-24 °C.

===== Troubleshooting =====
If temperature readings are incorrect or unstable:
  * Check wiring and verify analog input connection (A5).
  * Verify correct resistor value in voltage divider.
  * Ensure accurate Steinhart-Hart constants are used.