AUTOMATIC TEMPERATURE BASED FAN SPEED CONTROLLER (Electronics project)

AUTOMATIC TEMPERATURE BASED FAN SPEED CONTROLLER

TECHNICAL SPECIFICATIONS:

Title of the project                  :           Automatic Temperature Based Fan Speed Controller

Domain                                   :           Embedded Systems Design

Software                                  :           Embedded C, Keil, Proload

Microcontroller                       :           AT89S52

Power Supply                          :           +5V, 500mA Regulated Power Supply

                                                            +12V, 500mA Regulated Power Supply

Display                                    :           a) LCD

                                                            b) LED

LCD                                        :           HD44780 16-character, 2-line (16X2)

LED                                        :           5mm White-in-Red, 5mm White-in-Blue

Crystal                                     :           11.0592MHz

Relays                                     :           SPDT 12V

Temperature Sensor                :           LM35

ABSTRACT:

This project is a standalone automatic fan speed controller that controls the speed of an electric fan according to our requirement. Use of embedded technology makes this closed loop feedback control system efficient and reliable. Micro controller (AT89S52) allows dynamic and faster control. Liquid crystal display (LCD) makes the system user-friendly. The sensed temperature and fan speed level values are simultaneously displayed on the LCD panel. 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. AT89S52 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 Traic to control the fan speed.

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.

Block Diagram: