# That's Hot

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## Introduction: That's Hot

### Teacher Notes

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## Step 2: How to Do It?

### Example Code :

```#include
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
int buttonPin = 9; // pushbutton pin
const int temperaturePin = 0; //Temperature sensor pin
float voltage, degreesC, degreesF;
int displaysetC, displaysetF; //The value used to display the disired temperature
float set;  //The Value read from potentiometer
const int PotentiometerPin = 1; //PotentiometerPin
boolean button; //The button pushed or not
int buttonState;//Variables to hold the pushbutton states
const int led = 13; // LED pin
void setup() {
// Set up the pushbutton pins to be an input:
pinMode(buttonPin, INPUT);
// Set up the LED pin to be an output:
pinMode(led, OUTPUT);
}
void loop() {
Potentiometer();
Temperature(set);
Button();
LCDdisplay();```
```}
int Potentiometer() //Read the value from potentiometer and return it.
{
set = set / 32; //Make the value fit Fahrenheit
set = set + 60;
return (set);
}
float Temperature(float set) {
voltage = analogRead(temperaturePin) * 0.004882814;
degreesC = (voltage - 0.5) * 100.0;
degreesF = degreesC * (9.0 / 5.0) + 32.0;

int barD = (int) set; //Round the value from potentiometer
set = (float) barD;
displaysetC = set - 32;         //Make the value into 5-33 to fit Celsius
displaysetC = displaysetC * 9;
displaysetC = displaysetC / 5;
displaysetC = displaysetC - 40;
displaysetC = displaysetC / 2;
displaysetF = set;```
```}
int Button() {
// read the current pushbutton states into a variable
if (buttonState == LOW) { //If the button pressed, switch the state
button = !button;
}
}
void LCDdisplay() {
int barF = (int) degreesF;    //Round the value before display
degreesF = (float) barF;
int displayF = degreesF;
int barC = (int) degreesC;
degreesC = (float) barC;
int displayC = degreesC;
lcd.begin(16, 2);
if (button == true) {```
```    lcd.print(displayF);
lcd.print(" Fahrenheit");
lcd.setCursor(0, 1);
lcd.println(displaysetF);
lcd.println("DesiredTemp");
if (displayF > displaysetF) {
digitalWrite(led, LOW);
}
else {
digitalWrite(led, HIGH);
}
}
if (button == false) {
lcd.print(displayC);
lcd.println(" Celsius");
lcd.setCursor(0, 1);
lcd.println(displaysetC);
lcd.println(" DesiredTemp");
if (displayC > displaysetC) {
digitalWrite(led, LOW);
}
else {
digitalWrite(led, HIGH);
}```
```  }
delay(500);
}```

## Step 3: Important Code

// include the library code:

#include

// initialize the library with the numbers ofthe interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

// set up the LCD's number of columns and rows:
lcd.begin(16, 2);

// Print a message to the LCD.
lcd.print("hello, world!");

// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);

180 15K
239 32K
121 11K

## Discussions

What are the values of the resistors and potentiometer you use? Which temp sensor is it?