Watch the Video Tutorial part 1:

An automatic temperature control system has the ability to monitor and control the temperature of a specified space without human intervention. The primary purpose is to manage the temperature of a given area based on settings by a user of the system.

Figure 1: Automatic Temperature Control Block diagram

This project uses a PIC microcontroller to automatically control the temperature of an area. This area could be a small plant, a house or any place or device that require a controlled temperature like an incubator (egg) for example. Figure 1 shows the block diagram of the system to be designed. The desired temperature setting is entered using a keypad. The temperature of the area is measured using an analog temperature sensor, the LM35 precision integrated-circuit temperature sensor is used for this.

The microcontroller reads the temperature every 10 s and compares it with the desired value. If the desired value is higher than the measured value, then the heater is turned ON to heat the area. The heater is switched OFF once the desired temperature is reached. If on the other hand the measured value is higher than the desired value, then the fan is switched ON to cool off the area until the required temperature is reached. An LCD display shows the measured temperature continuously.

Figure 2 shows the circuit diagram of the project. The LCD is connected to PORTC. The LM35 precision analog temperature sensor chip is connected to the analog input pin AN0 (RA0). A 3×4 keypad is connected to PORTB. The ‘*‘ key of the keypad is used to clear the value entered during the temperature setup and the ‘#‘ key is used to ENTER (save) the setting. The heater and the fan are controlled using transistors and relays connected to pins RD0 and RD1 of the microcontroller respectively.

Figure 2: Automatic Temperature Control Circuit diagram

MikroC Source Code

Watch the Video Tutorial part 2: 

Watch the Video Tutorial part 3: 

Project PCB

EasyEDA is a a great and above all free web based circuit design, simulation and printed circuit boards (PCB) design tool for electronic hobbyists, engineers, teachers, students, makers and enthusiasts. We’re gonna design our project PCB using EasyEDA. for more information, please read: Getting Started with EasyEDA a web-based PCB Design Software

Figure 3: Automatic Temperature Control PCB

You can download the full project files (MikroC source code, Proteus Schematic design and PCB Gerber files) below here.
All the files are zipped, you will need to unzip them (Download a free version of the Winzip utility to unzip files).

MikroC Source Code: Automatic Temp Control MikroC

Proteus Schematic: Automatic Temp Control Proteus Schematic

PCB Gerber files: pcb-gerber