“MICROCONTROLLER BASED TEMPERATURE MEASUREMENT
AND CONTROLLING”
‘SUMMER TRAINING PROJECT REPORT’
SUBMITTED BY: -MANISH PHOGAT
ROLL NO: - 07-ECE-158
GURGAON INSTITUTE OF
ACKNOWLEDGEMENT
This is to acknowledge that our project “Temperature controller” has been the outcome of the sincere efforts of our
team and the immense, timely guidance and motivation of Mr. Ashish, Prolific Technologies, Mumbai.
Our project has been a success due to the combination of his support and our handwork.
CERTIFICATE
This is to certify that MANISH PHOGAT,
ENROLLMENT NO. : 1571562807, a student
of E.C.E from Northern India
Engineering College, IP university has done the summer training from Prolific Technologies.
The project work entitled
“MICROCONTROLLER BASED
TEMPERATURE MEASUREMENT AND CONTROLLING” embodies the
original work done during the above project training period.
(Pooja Mendiratta)
(HOD-ECE)
INDEX
1. PROFILE OF THE COMPANY. 2. PROJECT INTRODUCTION.
3. PROJECT METHODOLOGY 3.1 HARDWARE DESCRIPTION 3.1.1 8051 microcontroller 3.1.2 Temperature sensor DS1620 3.1.3 Brushless DC fan 3.1.4 LCD 3.1.5 Voltage Regulator 3.1.6 Power Supply 3.1.7 PCB 3.1.8 Capacitor 3.1.9 Resistor 3.1.10
3.2 SOFTWARE DESCRIPTION 3.3 HOW IT WORKS? 4.FUTURE PROSPECTS 5.CONCLUSION 6.BIBLIOGRAPHY
1.PROFILE OF THE COMPANY Prolific Technology Inc., a leading IC design house and ASIC design service provider, was founded in November 1997 by a group of highly experienced
and specialized technical engineers. The Company started out by developing
Smart I/O IC solutions, focusing on niche USB/IEEE 1394 bridge controller
products. The Company then also
ventured in the Mixed-Mode technology development, successfully designing
Brushless Motor Driver IC and Hall sensors. With the future towards 3C integration, the Company will devote
more efforts in SOC development as well as integration of competitive multimedia (MPEG-4/JPEG/MP3) and GPS
products. The Company will also
continue to introduce new technologies for existing IC product base that will
solutions. Through System Integration technology, Prolific is envisioning
herself to grow from a Professional IC Design House to a leading SOC Core Technology Pioneer.
Prolific's corporate training clients
include many blue-chip companies such as Sesa Goa, Aditya Birla Group
companies, Ordinance factories, Garware Polyesters, Indian Rayon, Indal, ITC,
Reliance Industries, India Cements, Saw Pipes, IPCL, GAIL etc.
2.PROJECT INTRODUCTION Any electronic system which has some intelligence and is dedicated to specific task are termed as embedded systems.
Embedded systems are real time and
standalone. Our project “ Temperature controller” employs the use of DS1620 temperature sensor via
8051microcontroller using lcd
interfacing. A Microcontroller is a single computer chip that executes a user
program, normally for the purpose of
controlling some device-hence the name. 8051 is a Microcontroller developed by Intel. Program can be contained in either second chip called EPROM or within the same chip as microcontroller itself.
This Project is used to indicate the temperature and it is also used as controller. The system will get the
it will display the temperature over the LCD and this temperature was compared with the value stored by the user and if the Room temperature goes beyond the Preset temperature then Brushless Fan is turned ON to lower the temperature of room. The System is fully controlled by the microcontroller 8051.
All the above functions are monitored and controlled by the 8 bit
microcontroller 8051.
This Project is used to control the Fan
action according to the temperature and it also indicates the temperature. The
system will get the temperature from the IC (DS1620).
With the DS1620 you may set
breakpoints to turn a thermostat on/off.
3.PROJECT METHODOLOGY
Hardware used:: 3.1.1 8051 microcontroller 3.1.2 Temperature sensor DS1620 3.1.3 Brushless DC fan 3.1.4 LCD 3.1.5 Voltage Regulator 3.1.6 Power Supply 3.1.7 PCB 3.1.8 Capacitor 3.1.9 Resistor
3.1.1 8051 microcontroller
Difference between a microprocessor and a microcontroller
A microprocessor has no RAM , ROM or I/O ports on the chip itself .A
microcontroller has a CPU( a
microprocessor) in addition to a fixed amount of RAM ,ROM,I/O and a timer all on a single chip.In other words, the processor , RAM, ROM, I/o ports, and timer are all embedded together on one chip; therefore, the designer cannot add any external memory, I/O or timers to it. The fixed amount of on chip ROM,
RAM and the number of I/O ports in microcontroller makes them ideal for many applications in which cost and space are critical.
In 1981, Intel introduced an 8-bit
128 bytes of RAM, 4K bytes of on chip ROM ,two timers, one serial port and 4 ports( each 8-bits wide).
Pin
configuration of µC
It is a 40 pin DIP configuration which operates on 5V.
Supports 12-clock (default) or 6-clock mode selection via software or ISP.
• Pin 9 : connected to Reset
• Pin 18,19 : connected to crystal
(to provide the required frequency to work on).
• Pin 29 : PSEN ,it is a read strobe
to external program memory.
• Pin 30 : ALE, It enables the
address latch for port 0
• Pin 31: EA (when low, enables
code to be fetched from external memory).
• Pin no. 1 to 8: Port 1. • Pin no. 10 to 17: Port 3. • Pin no. 21 to 28: Port 2.
• Pin no. 32 to 39: Port 0.
PIN DESCRIPTION
VCC: Supply voltage during normal, Idle and Power Down operations.
VSS: Circuit ground.
Port 0,1,2,3: These are 8-bit open drain bidirectional I/O port. They receive the code bytes during EPROM
programming, and outputs the code bytes during program verification.
RST: Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device. The port pins will be driven to their reset
condition when a minimum VIH1
voltage is applied whether the oscillator is running or not. An internal pulldown resistor permits a power-on reset with only a capacitor connected to VCC.
ALE/PROG: Address Latch Enable
output signal for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during EPROM programming for
the 87C51. In normal operation ALE is emitted at a constant rate of 1/6 the
oscillator frequency, and may be used for external timing or clocking purposes.
Note, however, that one ALE pulse is skipped during each
access to external Data Memory.
PSEN: Program Store Enable is the Read strobe to External Program Memory.
When the 87C51/BH is executing from Internal Program Memory, PSEN is
inactive (high). When the device is
Memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to External
Data Memory.
EA/VPP: External Access enable,EA must be strapped to VSS in order to
enable the 87C51/BH to fetch code from External Program Memory locations
starting at 0000H up to FFFFH. Note,
however, that if either of the Lock Bits is programmed, the logic level at EA is
internally latched during reset. EA must be strapped to VCC for internal program execution.This pin also receives the
programming supply voltage (VPP) during EPROM programming.
XTAL1: Input to the inverting oscillator amplifier.
XTAL2: Output from the inverting oscillator amplifier.
OSCILLATOR CHARACTERISTICS XTAL1 and XTAL2 are the input and output, respectively,of an inverting amplifier which can be configured for use as an on-chip oscillator.To drive the device from an external clock
source,XTAL1 should be driven, while XTAL2 is left unconnected.
3.1.2 IC-DS1620
The DS1620 Digital Thermometer and Thermostat provides 9-bit temperature readings which indicate the
temperature of the device. With three thermal alarm outputs, the DS1620 can also act as a thermostat. THIGH is
driven high if the DS1620's temperature exceeds a user defined temperature TH. TLOW is driven high if the DS1620's temperature falls below a user defined temperature TL.
Pin Description
User-defined temperature settings are stored in nonvolatile memory, so parts can be programmed prior to insertion in a system, as well as used in standalone applications without a CPU. Temperature settings and
temperature readings are all
communicated to/from the DS1620 over a simple 3-wire interface.
DS1620 Digital Thermometer and Thermostat requires no external
components .Supply voltage range covers from 2.7V to 5.5V, Measures
0.5°C increments; Fahrenheit equivalent is -67°F to +257°F in 0.9°F increments. Temperature is read as a 9-bit value
Converts temperature to digital word in 1 second (max) Thermostatic settings are user-definable and nonvolatile. Data is read from/written via a 3-wire serial interface (CLK, DQ, RST ).
DESCRIPTION: The DS1620 Digital Thermometer and Thermostat provides 9–bit temperature readings which
indicate the temperature of the device. With three thermal alarm outputs, the DS1620 can also act as a thermostat. THIGH is driven high if the DS1620’s temperature is greater than or equal to a
user–defined temperature TH. TLOW is driven high if the DS1620’s temperature is less than or equal to a user–defined temperature TL. TCOM is driven high when the temperature exceeds TH and stays high until the temperature falls below that of TL.User–defined
temperature settings are stored in
nonvolatile memory, so parts can be programmed prior to insertion in a system, as well as used in standalone applications without a CPU.
OPERATION AND CONTROL:
The DS1620 must have temperature settings resident in the TH and TL registers for thermostatic operation. A configuration/status register also
determines the method of operation that the DS1620 will use in a particular application and indicates the status of the temperature conversion operation. The configuration register is defined as follows:
CONFIGURATION/STATUS REGISTER:
where
DONE = Conversion Done Bit. 1=conversion complete, 0=conversion in progress. The power-up/POR state is a 1. THF = Temperature High Flag. This bit will be set to 1 when the temperature is greater than or equal to the value of TH. It will remain 1 until reset by writing 0 into this location or by removing power
from the device. This feature provides a method of determining if the DS1620 has ever been subjected to temperatures above TH while power has been applied. The power-up/POR state is a 0.
TLF = Temperature Low Flag. This bit will be set to 1 when the temperature is less than or equal to the value of TL. It will remain 1 until reset by writing 0 into this location or by removing power from the device. This feature provides a method of determining if the DS1620 has ever been subjected to temperatures below TL while power has been applied. The power-up/POR state is a 0.
NVB = Nonvolatile Memory Busy Flag. 1=write to an E2 memory cell in progress. 0=nonvolatile
memory is not busy. A copy to E2 may take up to 10 ms. The power-up/POR state is a 0.
CPU = CPU Use Bit. If CPU=0, the CLK/ CONV pin acts as a conversion start control, when RST is low. If CPU is 1, the DS1620 will be used with a CPU communicating to it over the 3–wire port, and the operation of the CLK/CONV pin is as a normal clock in concert with DQ and RST . This bit is stored in nonvolatile E2 memory, capable of at least 50,000 writes. The DS1620 is shipped with CPU=0.
1SHOT = One–Shot Mode. If 1SHOT is 1, the DS1620 will perform one temperature conversion upon reception of the Start Convert T protocol. If 1SHOT is 0, the DS1620 will continuously perform temperature
conversion. This bit is stored in nonvolatile E2 memory, capable of at least 50,000 writes. The DS1620 is shipped with 1SHOT=0.
3.1.3 Brushless DC Fan
Brushless DC fans are usually available at three nominal voltages: 12V, 24V and 48V. If the system has regulated power supply in one of these, then a brushless DC fan may be selected which will give the exact performance required,
regardless of the AC input variables which plague AC fans.
Because the speed and airflow of a typical DC fan is proportional to the
used to meet different applications by setting the supply voltage to what will give the desired airflow.
Brushless DC fans do not draw constant currents. The choice of the power source along with the addition of other
peripheral devices will be affected by the type and number of DC fans and their
motor current characteristics. Throughout the rotational cycle and particularly at
commutation, the currents will fluctuate from minimum to maximum.
Pin desriptions: Vss : GRND
Vcc : Power supply
RS : RS=0 to select command register
R/W : R/W = 0 for write, R/W = 1 for read
E : Enable
In recent years LCD is finding widespread use due to their declining prices, ease of programming and many other reasons.
Advanced Interfacing 1 - LCD Display A Liquid Crystal Display is an electronic device that can be
used to show numbers or text.
There are two main types of LCD display, Numeric displays (used in watches, calculators etc) and
Alphanumeric text displays (often used in devices such as photocopiers and
mobile telephones).
The display is made up of a number of shaped ‘crystals’. In numeric displays these crystals are shaped into ‘bars’, and in alphanumeric displays the crystals are simply arranged into patterns of ‘dots’. Each crystal has an individual electrical connection so that each crystal can be controlled independently. When the crystal is ‘off’ (i.e. when no current is passed through the crystal) the crystal reflect the same amount of light as the background material, and so the crystals cannot be seen. However when the
crystal has an electric current passed through it, it changes shape and so absorbs more light. This makes the
and so the shape of the dot or bar can be seen against the background.
It is important to realise the difference between a LCD display and an LED
display. An LED display (often used in clock radios) is made up of a number of LEDs which actually give off light (and so can be seen in the dark). An LCD
display only reflects light, and so cannot be seen in the dark.
The LCD has 6 lines that can be connected directly to the PIC
microcontroller pins.
It is a good design practice to add a low value resistor (e.g. 330R) on the lines to protect against
static discharges. The 10k potentiometer connected to pin 3 is used to adjust the contrast of the display.
3.1.5 Voltage Regulator (7805)
Voltage Regulator usually having three legs converts varying input voltage and produces a constant regulated output voltage. They are available in a variety of outputs. The most common part numbers start with the numbers 78 or 79 and finish with two digits indicating the output voltage. The number 78 represents positive voltage and 79 negative one. The 78XX series of voltage regulators are
designed for positive input. And the 79XX series is designed for negative input.
3.1.6.Power Supply
The power supply supplies the required energy for both the microcontroller and the associated circuits. It is the most essential part of the circuit because to run its constituent IC’s circuit has to be provided with power. A power supply is a vital part of all electronic systems.
Most digital IC’s including microprocessors, microcontrollers operate on a +5V supply. A regulated power supply is a power supply whose output voltage remains fairly constant even though the load and/or the input voltage changes. A load is any electrical circuit, appliance, device that is connected to the output of the power supply.
Making a Printed Circuit Board is the first step towards building electronic equipment by any electronic industry. Printed Circuit Board are used for
housing components to make a circuit for compactness, simplicity of servicing and case of interconnection. Thus we can
define the P.C.B. as : Printed Circuit
Boards is actually a sheet of bakelite (an insulating material) on the one side of which copper patterns are made with holes and from another side, leads of
electronic components are inserted in the proper holes and soldered to the copper points on the back. Thus leads of
electronic components terminals are joined to make electronic circuit.
3.1.8 Capacitors
It is an electronic component whose function is to accumulate charges and then release it. To understand the concept of capacitance, consider a pair of metal plates which all are placed near to each other without touching. If a battery is connected to these plates the positive pole to one and the negative pole to the other, electrons from the battery will be attracted from the plate connected to the positive terminal of the battery. If the battery is then disconnected, one plate will be left with an excess of electrons, the other with a shortage, and a potential or voltage difference will exists between
them. These plates will be acting as capacitors.
Capacitors are of two types: -
(1) Fixed type like ceramic, polyester, electrolytic capacitors-these names refer to the material they are made of aluminum foil.
(2) Variable type like gang condenser in radio or trimmer.
In fixed type capacitors, it has two leads and its value is written over its body and variable type has three leads. Unit of measurement of a capacitor is farad
denoted by the symbol F. It is a very big unit of capacitance. Small unit capacitor are Pico-farad denoted by pf (1 pf=1/1000, 000,000,000 f) Above all, in case of electrolytic capacitors, its two terminal are marked as (-) and (+) so check it while using capacitors in the circuit in right direction. Mistake can destroy the capacitor or entire circuit in operational.
3.1.9 Resistance
Resistance is the opposition of a material to the current. It is measured in Ohms
(Ω). All conductors represent a certain amount of resistance, since no conductor is 100% efficient. To control the electron flow (current) in a predictable manner, we use resistors. Electronic circuits use calibrated lumped resistance to control the flow of current. Broadly speaking, resistor can be divided into two groups viz. fixed & adjustable (variable) resistors. In fixed resistors, the value is fixed & cannot be varied. In variable resistors, the resistance value can be varied by an adjuster knob. The most
common type of resistors used in our projects is carbon type. The resistance value is normally indicated by colour bands. Each resistance has four colours, one of the band on either side will be gold or silver, this is called fourth band and indicates the tolerance, others three band will give the value of resistance (see table). For example if a resistor has the following marking on it say red, violet, gold. Comparing these coloured rings with the colour code, its value is 27000 ohms or 27 kilo ohms and its
tolerance is ±5%. Resistor comes in various sizes (Power rating). The bigger, the size, the more power rating of 1/4 watts. The four colour rings on its body tells us the value of resistor value as given below. COLOURS CODE Black 0 Brown 1 Red 2
Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 Grey 8 White 9
The first rings give the first digit. The second ring gives the second digit. The third ring indicates the number of zeroes to be placed after the digits. The fourth
ring gives tolerance (gold ±5%, silver ± 10%, No colour ± 20%).
3.2 Software Description
For the development of Digital Thermostat for fan reprogrammable microcontroller is necessary. Two
options for reprogrammable
microcontrollers were considered. The first being the traditional ultraviolet light
(UV) erasable-memory type that has a quartz window and is exposed to UV to erase the contents prior to programming. This process can take 10 to 20 minutes to erase the memory. Microchip provides this option for the PIC16 series and the UV erasable devices are identified by the model number extension JW. These devices are produced in a ceramic dual-in-line package and are identical to the OTP (One Time Programmable) version except for the packaging and cost. The other option considered was the FLASH
based AT89C51 family, which is a new series of devices that employ electronically erasable memory. These devices are available in DIP or surface mount packages. The FLASH devices are more convenient to reprogram than the windowed version as they don't require exposure to UV light and hence the reprogramming time is much shorter.
The microcontroller chosen for the development system was the AT89S52.
This device is much cheaper than the windowed PIC16C73A-JW and since two microcontrollers are required this represents an immediate hardware saving. The AT89S52 has 8K of program memory and has the capability to write to its own memory. The use of a FLASH device for development also provides the option to use FLASH microcontrollers in the final design making the system fully up gradable. This allows modification of the microcontroller software to support expansion and the addition of other
sensors and inputs. The original intention was to use the FLASH AT89S52 to develop software using the development system and employ an AT89S52 unit in the final application. The OTP devices are cheaper and this reduces the cost per unit. There are some differences between the device families, which need to be considered when using the FLASH to develop code for the developed system.
3.3 HOW IT WORKS? Interfacing::
CODING: #include <REG51F.H> #include <REG51F.H> #include<stdio.h> //---ds1620 initialization and function definitions---sbit dq=P0^0; sbit clk=P0^1; sbit rst=P0^2;
sbit tcom=P0^3; sbit fan=P0^5;
unsigned char temp,temp1,temp2; unsigned char ds1,ds2,ds3;
void init_ds1620();
void wt_ds1620(unsigned char a);
void wt_ds1620_reg(unsigned char a); unsigned char rd_ds1620();
void process(unsigned char);
//---
---code disp_lut[] = {'0','1','2','3','4','5','6','7','8','9'};
//---lcd initializations and function
definitions---void delay_ms(unsigned int); void data_wr(unsigned char); void cmd_wr0(unsigned char); void cmd_wr(unsigned char); void map(unsigned char);
void pulse(); sbit RS=P1^1; sbit RW=P1^2; sbit E=P1^3; sbit D4=P1^4; sbit D5=P1^5; sbit D6=P1^6; sbit D7=P1^7; //--- ---void main()
{ tcom=0; lcd_init(); init_ds1620(); while(1) { rst=1; wt_ds1620(0xee); rst=0; delay_ms(2);
delay_ms(2); rst=1; wt_ds1620(0xaa); temp2=rd_ds1620(); rst=0; process(temp2); if(temp2>temp) { fan=1;
cmd_wr(0x80); delay_ms(5); data_wr('F'); delay_ms(5); data_wr('A'); delay_ms(5); data_wr('N'); delay_ms(5); data_wr(' '); delay_ms(5); data_wr('I');
delay_ms(5); data_wr('S'); delay_ms(5); data_wr(' '); delay_ms(5); data_wr('O'); delay_ms(5); data_wr('N'); delay_ms(5); data_wr(' '); delay_ms(5);
cmd_wr(0xc0); delay_ms(5); data_wr('T'); delay_ms(5); data_wr('e'); delay_ms(5); data_wr('m'); delay_ms(5); data_wr('p');
delay_ms(5); data_wr('='); delay_ms(5); data_wr('='); delay_ms(5); data_wr('>'); delay_ms(5); data_wr(' '); delay_ms(5); data_wr(' '); delay_ms(5);
data_wr(ds3); delay_ms(5); data_wr(ds2); delay_ms(5); data_wr(ds1); delay_ms(5); } else { fan=0 ; cmd_wr(0x80); delay_ms(5);
data_wr('F'); delay_ms(5); data_wr('A'); delay_ms(5); data_wr('N'); delay_ms(5); data_wr(' '); delay_ms(5); data_wr('I'); delay_ms(5); data_wr('S');
delay_ms(5); data_wr(' '); delay_ms(5); data_wr('O'); delay_ms(5); data_wr('F'); delay_ms(5); data_wr('F'); delay_ms(5); cmd_wr(0xc0);
delay_ms(5); data_wr('T'); delay_ms(5); data_wr('e'); delay_ms(5); data_wr('m'); delay_ms(5); data_wr('p'); delay_ms(5); data_wr('=');
delay_ms(5); data_wr('='); delay_ms(5); data_wr('>'); delay_ms(5); data_wr(' '); delay_ms(5); data_wr(' '); delay_ms(5); data_wr(ds3); delay_ms(5);
data_wr(ds2); delay_ms(5); data_wr(ds1); delay_ms(5); } } } void init_ds1620() { rst = 1;
wt_ds1620(0x0c); //writing permission to the control register
wt_ds1620(0x03); //writing data into the control resiter
rst = 0; delay_ms(2); delay_ms(2); rst=1; wt_ds1620(0x01); //writing high temp limit to TH
rst=0; delay_ms(2); delay_ms(2); rst=1; wt_ds1620(0xa1); temp=rd_ds1620(); rst=0;
delay_ms(2); delay_ms(2);
rst=1;
wt_ds1620(0x02); //writing high temp limit to TL
wt_ds1620_reg(70); // data into TL rst=0;
delay_ms(2); delay_ms(2);
rst=1; wt_ds1620(0xa2); temp1=rd_ds1620(); rst=0; } //---void wt_ds1620(unsigned char a) {
for (k=0; k<8; k++) { clk=0; dq = (a & b); /* Send bit to 1620 */ clk=1; b=(b<<1); /* Setup to send next bit */
}
return;
}
void wt_ds1620_reg(unsigned char a)
{
unsigned char k,b=1;
for (k=0; k<10; k++) { clk=0; dq = (a & b); /* Send bit to 1620 */ clk=1; b=(b<<1); /* Setup to send next bit */
} return;
}
unsigned char rd_ds1620(void) {
unsigned char j,k = 0, b = 1; dq=1;
{ clk = 0; if(dq) k |= b; clk = 1; b = (b<<1); } return k; }
unsigned char read_temp() { return 0; } void lcd_init() { delay_ms(15); cmd_wr0(0x30); delay_ms(5);
cmd_wr0(0x30); delay_ms(5); cmd_wr0(0x30); delay_ms(5); cmd_wr0(0x20); delay_ms(5); cmd_wr(0x14); delay_ms(5); cmd_wr(0x28); delay_ms(5); cmd_wr(0x06);
delay_ms(5); cmd_wr(0x0c); delay_ms(5); cmd_wr(0x80); delay_ms(5); cmd_wr(0x01); delay_ms(5); }
void cmd_wr0(unsigned char value) {
RS=RW=0; map(value); pulse();
}
void cmd_wr(unsigned char value) {
cmd_wr0(value); value=value<<4; cmd_wr0(value); }
void map(unsigned char value) { P1=((P1&0x0F)|(value&0xF0)); } void pulse() { E=1; delay_ms(1);
E=0; }
void data_wr(unsigned char value) { RS=1; RW=0; map(value); pulse(); value=value<<4; map(value);
pulse(); }
void delay_ms(unsigned int time) {
unsigned int i, j;
for( i = 0; i < time; i++ ) {
for( j = 0; j < 50; j++ ); }
void process(unsigned char value) { value=value/2; ds1=disp_lut[value%10]; ds2=disp_lut[(value/10)%10]; ds3=disp_lut[value/100]; }
WORKING:
In this project the ambient temperature will be sensed by 8051-compatible temperature sensor DS1620 and displayed on LCD display. A temperature sensor DS1620 is used for sensing the ambient temperature. The thermostat outputs of the DS1620 allow it to directly control heating and cooling devices. Fan driven ON if the Device exceeds a predefined limit set within the TH Register. THIGH can be used to indicate that a high temperature tolerance boundary has been met or exceeded, or it can be used as part of a closed loop
system to activate a cooling system and deactivate it when the system temperature returns to tolerance. By using this technique it is possible to sense the temperature.
4.FUTURE PROSPECT
This is easily convertible and compatible to other applications….
• Irrigation Control :- This
requires the humidity sensor, the rest of the task remains the same. The maximum water level should be set and the sensed humidity will turn the motor on/off.
• AC/Cooler Switching :- This too
requires temperature sensing and hence management of switching off & on.
• Meteorological Department
• In Chemistry Labs :- This can be
used to get rid of heat when the Exothermic Reactions are being performed in the labs.
• As Fire-Extinguishers : - As
sensed temperature will exceed its set value, carbon dioxide gas
comes out.
• Metro Trains :- Temperature of
air conditioners can be set plus the sixth sense technology can be
maintained.
• Temperature Control in Refrigerators
• Automatic Geysers :- The task
will be to control the temperature of the water coming out while the geyser is on.
5.CONCLUSION
No matter where we look in the modern world, the evidence of the embedded
revolution is starting to creep into every aspect of modern life. From microchip devices that can be implanted into the skin to futuristic software solutions for
handheld units, embedded technology and the results of embedded technology have started to transform the form and shape of the technological society
BIBLIOGRAPHY
• 8051 Microcontroller and embedded systems : Muhammad Ali Mazidi, Janice Gillispie Mazidi & Rolin D. McKinlay
• www.howstuffworks.com • www.alldatasheets.com • www.dalsemi.com
