ARDUINO BASED AUTOMATIC TEMPERATURE BASED FAN SPEED CONTROLLER SUBMITTED BY

ABSTRACT This practical temperature controller controls the temperature of any device according to its requirement for any industrial applicationIt also has a feature of remote speed control. The LM-35 Analog Temperature device is interfaced to analog pin of Arduino board,where it has built in ADC which converts these analog reading and displays it on a LCD, which indicate the temperature of the device User-defined temperature settings can be done using push buttons provided through Arduino board.

BLOCK DIAGRAM

HARD WARE EQUIPMENTS POWER SUPPLY BLOCK ARDUINO LED L293D,DC MOTOR. LM35 LCD (LIQUID CRYSTAL DISPLAY) 1N4007 RESISTORS & CAPACITORS

EMBEDDED SYSTEMS

ARDUINO The Arduino microcontroller is an easy to use yet powerful single board computer that has gained considerable traction in the hobby and professional market. The Arduino is open-source, which means hardware is reasonably priced and development software is free.

Image of development board

Features of Duemalinove The Duemalinove board features an Atmel ATmega328 microcontroller operating at 5 V with 2 Kb of RAM, 32 Kb of flash memory for storing programs and 1 Kb of EEPROM for storing parameters. The clock speed is 16 MHz, which translates to about executing about 300,000 lines of C source code per second

…..contd The Arduino programming language is a simplified version of C/C++. If you know C, programming the Arduino will be familiar. If you do not know C, no need to worry as only a few commands are needed to perform useful functions.

LIQUID CRYSTAL DISPLAY (LCD) Most common LCDs connected to the microcontrollers are 16x2 and 20x2 displays. This means 16 characters per line by 2 lines and 20 characters per line by 2 lines, respectively. The standard is referred to as HD44780U, which refers to the controller chip which receives data from an external source (and communicates directly with the LCD.

If an 8-bit data bus is used the LCD will require 11 data lines LCD BACKGROUND If an 8-bit data bus is used the LCD will require 11 data lines (3 control lines plus the 8 lines for the data bus) The three control lines are referred to as EN, RS, and RW EN=Enable (used to tell the LCD that you are sending it data) RS=Register Select (When RS is low (0), data is treated as a command) (When RS is High(1), data being sent is text data ) R/W=Read/Write (When RW is low (0), the data written to the LCD) (When RW is low (0), the data reading to the LCD)

LM 35 TEMPARATURE SENSOR LM35 are used to sense the heat and an IC ADC0808 is used to convert the data into digital. LM35 digital sensor has got 3 pin’s i.e., VCC, GND and output pin’s when LM35 is heated the voltage at output pin increases, it is connected to the analog to digital convertor IC (ADC). The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature. The LM35 thus has an advantage over linear temperature sensors calibrated in Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade scaling.

…..contd The LM35 does not require any external calibration or trimming to provide typical accuracies of ±1⁄4˚C    at room temperature and ±3⁄4˚C over a full −55 to +150˚C temperature range.

MOTOR driver L293D L293D is a dual H-bridge motor driver integrated circuit (IC). Motor drivers act as current amplifiers since they take a low-current control signal and provide a higher-current signal. This higher current signal is used to drive the motors. L293D contains two inbuilt H-bridge driver circuits. In its common mode of operation, two DC motors can be driven simultaneously, both in forward and reverse direction.

Operation of motor driver L293D has 2 set of arrangements where one set has input 1, input 2, output 1 and output 2 and other set has input 3, input 4, output 3 and output 4, according to block diagram if pin no 2 & 7 are high then pin no 3 & 6 are also high. If enable 1 and pin number 2 are high leaving pin number 7 as low then the motor rotates in forward direction. If enable 2 and pin number 10 are high leaving pin number 15 as low then the motor rotates in forward direction.

Contd.. If enable 1 and pin number 2 are low leaving pin number 7 as high then the motor rotates in reverse direction. If enable 2 and pin number 15 are high leaving pin number 10 as low then the motor rotates in forward direction.

DC- MOTOR A DC motor is an electric motor that runs on direct current (DC) electricity. In any electric motor, operation is based on simple electromagnetism. A simple 2-pole DC electric motor (here red represents a magnet or winding with a "North" polarization, while green represents a magnet or winding with a "South" polarization). Every DC motor has six basic parts -- axle, rotor (a.k.a., armature), stator, commutator, field magnet(s), and brushes.

BIBILOGRAPHY The 8051 Microcontroller and Embedded systems” by Muhammad Ali Mazidi and Janice Gillispie Mazidi , Pearson Education. ATMEL 89S52 Data Sheets. www.atmel.com www.beyondlogic.org www.wikipedia.org www.howstuffworks.com www.alldatasheets.com

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