1. Build your project as per following block diagram. You may use equivalent components. By the way: How are you going to track the time of the day? Probabaly, you need a RTC -- DS1307 or DS3231.
Figure-1: Block diagram for UNO-DS18B20-I2CLCD based Temperature Controller
2. The Flow Chart (given below) is the approximate program that will regulate your temperature cycle.
Figure-2: Flow Chart describing the Control Program for the Temperature Controller of Fig-1.
3. I am giving below the basic two functions of the Arduino IDE. Try to put some codes based on the given Flow Chart or of your own strategy. Please post your codes to get the next help. If you find problems to write codes for the DS18B20, substitute it (for the time being) calling the function getTemp();
void setup()
{
}
void loop()
{
getTemp(); //acquiring Temperature from DS18B20
delay(2000); //acquire temp at 2-sec interval (adjustable)
}
void getTemp()
{
//code here to acquire Temperature from DS18B20 using DallasTemperatures Library functions
}