Abstract :

The aim of this project is to control the temperature of the fluid and to maintain the same temperature by consuming small amount of power to maintain it. Thus saving the input power and maintaining the fluid temperature constant to the required value. This project consists of three modules, first the sensing unit, second the analog to digital conversion unit and the final module is controlling and power regulating unit.

    In this project we are taking one heating element to heat the fluid for which the power is fed from the power control circuitry. The output of the heating element is sensed through a temperature sensor, which is fed to the embedded controller with the use of ADC interface. The embedded controller compares the sensor value with the predefined value for which it should maintain constant temperature and sends signals to the power control circuitry. In power control circuitry, the power is controlled using PWM technique i.e., the input power to the heating element is controlled with the pulse width modulation technique, such that to maintain the constant temperature by consuming less power after attaining the desired temperature.

     The main purpose of controlling the temperature of the fluid is to save the power i.e., the power can be saved from overheating of the heating element which is frequent in our daily use, as well as this system avoids the dilapidation of the heating element with this overheating process. 

     This project uses regulated 5V, 500mA power supply. Unregulated 12V DC is used for relay. 7805 three terminal voltage regulator is used for voltage regulation. Full wave bridge rectifier is used to rectify the ac output of secondary of 230/12V step down transformer.

TECHNICAL SPECIFICATIONS:

HARDWARE:

Micro controller         :           AT89S52

Crystal                        :           11.0592 MHz

ADC                            :           ADC0804

LCD                            :           HD44780

LED                            :           5mm Red LED

Temperature sensor    :           LM35

Heating element         :           10 ohm 5Watt

Power supply

Transformer                :           12V step down  

Filter                           :           1000uf/25V

Voltage Regulator      :           7805

SOFTWARE:

Keil micro vision

Proteus

UC flash

APPLICATIONS:

• Industrial applications
• Automatic control systems