TEMPERATURE BASED FAN SPEED CONTROL

TEMPERATURE BASED FAN SPEED CONTROL

This project is a standalone Temperature based fan speed controller that controls the speed of the fan according to our requirement. Use of embedded technology makes this closed loop feedback control system efficient and reliable. Micro controller (AT89C51) allows dynamic and faster control. Liquid crystal display (LCD) makes the system user-friendly. It is very compact using few components and can be implemented for several applications including air-conditioners, water-heaters, snow-melters, ovens, heat-exchangers, mixers, furnaces, incubators, thermal baths and veterinary operating tables. AT89C51 micro controller is the heart of the circuit as it controls all the functions.

The temperature sensor LM35 senses the temperature and converts it into an electrical (analog) signal, which is applied to the micro controller through ADC. The analog signal is converted into digital format by the analog-to-digital converter (ADC). The sensed and set values of the temperature are displayed on the 16x2-line LCD. The micro controller drives control relays by means of ULN driver circuit to control the motor speed with the help of high wattage tagged wire wound resistor.

The micro controller controls FAN Speed through a ULN driver circuit. The Speed is controlled with the help of PWM technique.

This project uses regulated 5V, 500mA & 12V, 500mA power supply. 7805 and 7812 three terminal voltage regulators are used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/12V step down transformer. This project is useful in process industries for maintenance and controlling of Boilers temperature.

HARDWARE REQUIREMENTS:

1.      AT89S52

2.      REGULATED POWER SUPPLY

3.      LM35

4.      ADC MCP3208

5.      16*2 LCD Display

6.      DC FAN

7.      ULN2003 CURRENT DRIVER

SOFTWARE REQUIREMENTS:

1. Keil Compiler
2. ucFlash
3. Embedded C Code