[Need Help] LM35CZ based temperature controlled thermostat for Peltiers

Projects Programming
1

Hello guys, this is my first post and I want to know something about multitasking and button options.
So here is the code:

int val;
int tempPin = 1;
int aa;
int temp;
float ab;
int pelt = 12;

void setup()
{
  Serial.begin(9600);
  aa = 30;
  ab = 29.99;
  pinMode(12, OUTPUT);
}
void loop()
{
  val = analogRead(tempPin);
  float mv = ( val/1024.0)*5000; 
  float temp = mv/10;
  //float farh = (temp*9)/5 + 32;

  Serial.print("TEMPRATURE = ");
  Serial.print(temp);
  Serial.print("*C");
  Serial.println();
  //delay(250);
  
  if (temp < aa)
  {
    digitalWrite(pelt, HIGH);
  }
  else (temp > ab);
  {
    digitalWrite(pelt, LOW);
  }
}

I want to change and variables to button controlled. Like you press a button that changes the which is temp at which to stop cooling and it is from 15-> -20 (which -20 is don't stop cooling) and to be the temp which to start cooling and it should range from 45->15. The temperature is in celsius and something else is that I want to change is the delay and

digitalWrite(pelt, HIGH or LOW) to don't be timed but like On and Off

Then I would add a display, prefferably this one

And it would display °C and when you press a button to change max and min temp then it will display that for 5 sec and come back to °C displaying. My arduino is Arduino Leonardo and I don't have the LCD display yet. Thanks for helping

PS: The peltier would be switching off and on with a relay, that would be controlled with a bd139 NPN transistor due to low voltage arduino output

2

Do a google search for a arduino LCD menu library and find one with button input capabilities that suits your need - or better study such a code and develop something suiting your needs