Temperature change starts a heater

Hello, I am very new to Arduino. I am wanting to build a small system that will monitor the temperature and turn on a heater when the temperature drops below a specific reading, then turn it off when it the environment gets to another temperature. I want to use the mega 2560 microcontroller. I'm not sure what other components that I will need. Please reply with specifics. Or reply with good websites that I could visit to learn more about this type of project.

I am not looking for someone to do it for me. I am looking for help identifying the parts that I need, like a BOM.

These are the parts that I know I will need.

*Black Cased MEGA 2560 R3 Board ATmega2560-16AU CH340G
*DHT11 Temperature and Relative Humidity Sensor
*Yellow Serial IIC/I2C/TWI 2004 204 20X4 Character LCD Module Display
*Iot Relay - Enclosed High-power Power Relay for Arduino
*power supply

I think I need this also:
Sensor Shield Digital Analog Module Servo Motor for Arduino UNO R3 MEGA V5 SV2

Also, other than ebay and amazon, what are some good sources in the US for these parts?

Any help would be appreciated.

Thank everyone

I suggest buying your first products from Adafruit or Sparkfun (either directly or though Amazon). They definitely aren’t the cheapest, but the products should be reliable, and your purchases will help fund their tutorials and support forum, which you will find helpful.

Also, you don’t need a Mega for that project. An Uno would do.

I certainly would avoid DHT11 / 22, here's one I've had excellent results with (if you don't mind a few minutes soldering):

How big a space are you heating to what temperature difference between inside and outside?

If it is just temperature you are monitoring ditch the DHT11/22 and use a DS18B20

The DHT22 is a much better sensor than the DHT11 but indeed if you're not interested in the humidity get a dedicated temperature sensor.

You don't need a Mega for this project, an Uno or derivative (Nano, Micro) will do just fine. Can probably even be implemented on an ATtiny, but not as first project.

Thanks for your replies.

What do you mean with "Iot relay".


What do you mean with "Iot relay".