Final Report Theory(System Integrtion and Refrences

8/3/2019 Final Report Theory(System Integrtion and Refrences

1/45

Chapter 1

INTRODUCTION

1.1Project Title:

Microcontroller Based Remote Monitoring Gas Analyzer is a project to develop a remote

monitoring gas analyzer capable of monitoring gas pollutants at a range of about 100 meters

and check if their concentrations exceed above critical levels.

1.2 Project Description:

Our atmosphere is composed of various gases which support life in all extent. All these gases

have their definite role in human biological development. But now days due to various

reasons say industries, eradication of trees there is a huge imbalance in the concentration of

these gases which has a direct impact on the living creature of the earth. This imbalance can

be controlled to some extent if we get to know about their concentration in the atmosphere

and taking the action to have control over it.

In this project we are using sensors to detect if the concentration of two gases exceed above

critical levels and display it on the LCD using microcontroller. The transmitter will be kept in

the required location while receiver in the control room from where we can continuously

monitor the concentration of gases.

1.3 Block Diagram:

1


2/45

RF

Transmitter

HT-12E

Comp.

2

Sensor 1


3/45

HT-12D

Vref1

Comp.

Vref2

Fig: 1.3.1 Transmitter Section

Fig: 1.3.2 Receiver Section

3

RF ReceiverMicrocontrollerLCD DISPLAY


4/45

Explanation:

1. An input from the gas sensor is given to the anode follower and then to the comparator.

The comparator compares the input value with the predefined reference levels and gives the

output in the form of 0V or 3.54V (normal=0V, high = 3.54V).

2. An encoder receives this value and encodes the given data into a unique code and sends itto the transmitter to modulate the data.

3. Receiver receives the signal and demodulates it.

4. Decoder decodes the data into its original value fed by the comparator.

5. Microcontroller manipulates the data from decoder and accordingly displays it on the

LCD.

Instead of gas sensors light sensor (LDR) have been used. This has been done as gas

sensors were not easily available. It doesnt affect the concept of project as whatever

sensor is used it will give output in the form of electrical signal which will be

manipulated further.

1.

2.

1.4Application Areas:

1. SCADA (Supervisory control and data acquisition).

2. Industries to analyze the various gas concentrations.

3. Chimneys for monitoring exhaust gases etc.

1.4Resources Required:

1. Test and Measuring instruments such as

a) Digital Multimeter

b) Cathode ray oscilloscope

2. Tools such as

a) Cutter

b) Pliers etc.

1. Assembler and Programmer:

a) Keil

b) Proteus

c) Microcontroller burner device

4


5/45

Chapter 2

HARDWARE

2.1 Circuit Diagram :

5


6/45

6

Fig 2.1.1 Circuit diagram of transmitter section


7/45


8/45


9/45

Fig: 2.2.1.1.1 Pin Diagram of Encoder[1]

TE (Transmission Enabled) at pin no 14 should be low for encoder to encode and transmit

the bits. A graph between supply voltage and oscillator frequency for constant values of Rosc

for encoder has been shown below. This graph helps us in calculating the Rosc to be used in

encoder. Encoder used in our project works on supply voltage of 5V and oscillates on the

frequency of 3 KHz. Both values are used and using the graph Rosc was found to be 1M

Ohm which is connected between pins 15 and 16.

Fig:

2.2.1.1.2 Supply Voltage Vs Oscillator Frequency Graph for HT12E

3. RF transmitter (TWS-434):

9


10/45

RF transmitter (TWS-434A) is used in the transmitter section to transmit the encoded bits. It

modulates the bits received from encoder at a 434MHz carrier frequency using amplitude

shift keying. 17th pin of encoder is connected to the input 2 pin of transmitter. A helical

antenna is used for transmitting. For this a simple conducting wire is helically wound to

make the antenna. The length of the wire is calculated using /4, where is the wavelength

of the signal transmitted.

Fig: 2.2.1.1.3 TWS 434A

Calculation for antenna length:

Frequency 434 MHz

Wavelength = C/F

= 310 8 / 434 10 6

= 0.6901 m

Antenna Length = /4

= 0.1725 m

= 17.25 cm

4. Light Sensor:

Light Dependent Resistor (LDR) has been used as light sensor. Its resistance increases with

decrease in light intensity. It has been used in voltage divider circuit to vary output voltage

according to light intensity.[3]

Fig 2.2.1.1.4 Light

Dependent Sensor[3]

5. Anode Follower and Comparator:

10


11/45

LM358, an 8 pin IC, comprising of two operational amplifiers has been used for performing

dual function of anode follower and comparator. Anode follower is used to avoid loading

effect of sensors and to get same output voltage as input voltage. Comparator is used to

compare input voltage with the preset voltage levels set by using trim pot. It has been

operated at a voltage of 5V. If the voltage of positive terminal is greater than the voltage of

negative terminal the output voltage is 3.54V else output voltage is 0V.

Fig: 2.2.1.1.5 LM324

2.2.1.2 Working Principle:

LM35 and LDR continuously monitor change in temperature and light intensity respectively.

They are followed by anode follower and comparator. Anode follower continuously outputs

the same voltage as provided by the sensors. This voltage is supplied to positive terminals of

comparator. Negative terminals are set to the critical voltages set using potentiometer.

In case of temperature sensor when the temperature is below 40 degree Celsius, then less

than 40mV of voltage is received from the temperature sensor. This voltage is applied to

positive terminal of comparator. As we want critical temperature to be set to be 40 degrees

Celsius, thus critical voltage is set to be 40mV using trim pot at negative terminal of

comparator. In case when input voltage is less then critical voltage output of comparator is

11


12/45

0V. This makes green led to glow signifying normal temperature conditions. When

temperature exceeds critical temperature of 40 degrees, voltage also rises more than critical

voltage then output of comparator at pin 1 is 3.54V. This makes red led to glow signifying

abnormal temperature conditions.

In case of LDR when there is zero light intensity, input voltage of comparator is .10V.

Critical voltage is set at .33V. This makes 0V at output pin of comparator and makes greenled to glow. When LDR is kept at normal room light intensity at the time of day, voltage

level is 1.20V, this makes voltage exceed critical levels thus results in glow of red led.

The outputs of both sensors, whether high or low are sent data pins of encoder. Encoder

encodes them and transmits them using RF transmitter.

2.2.2. Receiver Section:

Receiver section includes:

1. Power supply

2. RF Receiver (RWS-434A)

3. Decoder (HT12D)4. Microcontroller (AT89C51)

5. LCD display

2.2.2.1. Circuit Description:

1. Power supply:

In the receiver section power supply is same as that of transmitter section to get constant

output voltage of 5V. It provides supply to receiver, decoder, microcontroller and LCD

display.

2. RF Receiver:

The RF Receiver used is RWS-434A. It receives the coded signal, demodulates it and sends

the codes serially to the decoder HT12D.

12


13/45

3. Decoder (HT12D):

Decoder is a versatile device which is used to decode the encoded data so as to retrieve the

original data. This also can only be done if the address of the encoder and decoder is

matched. If the address and encoded bit transmitted does not match the transmission is not

enabled. Pin no. 17 (VT) is the most important pin which shows the valid transmission

between the two sections, if pulled high.

The decoded data is then received from the four

data output pin (pin no. 10 to 13).

13

Fig: 2.2.2.1.1. RWS434 A


14/45

We have used 5V supply voltage at decoder which works at the frequency of 150

KHz which is 50 times that of encoders frequency and hence we get the Rosc of

51K Ohm according to the following graph.

4. Microcontroller:

AT89C51 is a 40 pin, 4K microcontroller which has been used to take in data inputs from

decoder. These inputs can be either 0V or 3.54V. If it receives 0V it considers it as 0 bit

input, if it receives 3.54V it considers it as 1 bit input. Range of 0 bit is less than 0.8V and

range of bit 1 is greater than 2.5V. It manipulates the input data according to software written

in it and displays the output on the LCD display. It has been operated at a typical voltage of

5V. A reset push button and crystal oscillator is also connected with microcontroller to reset

microcontroller when needed, and to provide oscillator frequency of 11.0592 MHz

respectively.

14

Fig: 2.2.2.1.2 HT12D

Fig: 2.2.2.1.3 Oscillator Frequency Vs Supply voltage HT12D


15/45

Fig: 2.2.2.1.4 Pin Diagram of AT89C51

4. LCD Display:

It is a 16 pin microcontroller display operated at a typical voltage of 5V. It has beeninterfaced with microcontroller to display whether the status of temperature sensor

and LDR is normal or high. This is done according to instructions given by

microcontroller to LCD display according to software written in microcontroller.

15


16/45

Fig: 2.2.2.1.5 LCD Display

2.2.2. Working Principle:

When the receiver unit comes in the range of transmitter unit continuously transmitting RF

signal, the whole receiver unit gets activated. The receiver unit receives RF signal at a

frequency of 434 MHz which actually is digital data including the binary code assigned to

particular transmitter and a carrier signal. Digital output is taken from pin 2 of RWS 434 and

received by decoder HT12D through data input pin (14th pin). The received serial input data

are compared three times continuously with the local address. If no error or unmatched codes

are found, the input codes are decoded and then transferred to the output pins. The VT (Valid

Transmission) pin (17th pin) gives high voltage and LED glows to indicate a validtransmission. The decoded bits of the two sensors are given to the microcontroller at pin no

P2.7 and P2.6, where P2.7 has been used for temperature sensor and P2.6 has been used for

light sensor.

There can be four situations which can arise. First situation is when both pins are at 0V. In

this case it is taken both inputs as 0 bit. In this situation microcontroller send data to display

on LCD that CO2 CONC NORMAL and NO2 CONC NORMAL. This is done using

software written in Microcontroller. Second situation is when P2.7 is high at 3.54 V and P2.6

is low at 0V, in this case LCD displays CO2 CONC HIGH and NO2 CONC NORMAL.

In third situation when P2.7 is low and P2.6 is high then microcontroller displays CO2

CONC NORMAL and NO2 CONC HIGH. When both pins are high fourth situation thenLCD displays CO2 CONC HIGH and NO2 CONC HIGH. In this way the controller

sitting in the controller room gets to know whether the sensors are exceeding their critical

voltages.

16


17/45

Chapter 3CIRCUIT FABRICATION

1.1Hardware Integration And Testing:

1.1.1 Transmitter Section:

It was divided in three sub-assemblies.

1. Power Supply:

Circuit was fabricated on PCB for making 5V power supply using step down transformer, bridge rectifier, LM7805, required resistors and capacitors as mentioned in the circuit

diagram. A red LED was connected in the end to signify if supply is working or not. Supply

was tested for 5V using Cathode Ray Oscilloscope.

2. Comparator along with Sensors:

LM35 temperature sensor was connected to the input of anode follower of LM358. It was

tested if with increasing temperature; voltage at the output of temperature sensor is

increasing proportionally or not, using soldering iron. Now the output voltage of anode

follower was checked if it is the same as input voltage using CRO. Input voltage at negative

terminal of comparator was set to be 40mV, using trim pot. Output voltage of comparatorwas checked from pin no1 using CRO. It was made sure that output voltage of 3.54V is only

received in the case when temperature exceeds 40 degrees, otherwise it should be 0V.

LDR was connected in series with a 47K ohm resistor. This value of resistance was

calculated using voltage dividing rule over a series network as the resistance of LDR in light

and dark were already measured to be 200K Ohm in dark and 50K Ohm in day light using

digital multimeter. The value of resistance was calculated such so that there should bemaximum difference in voltages across LDR in light and dark. Same procedure was repeated

as in case of temperature sensor to check if anode follower and comparator are working

properly. The value of resistance in trim pot was set such that comparator gives 3.54V in day

light and 0V in dark.

3. Encoder with RF transmitter:

Encoder HT12E was connected as shown in the circuit diagram. Output voltages of both

comparators were provided to the lower most data pins of encoder. RF transmitter was

connected the same way as shown in the circuit diagram. FSK waveform of encoder was

checked using CRO.

17


18/45

3.1.2 Receiver Section:

It was also divided in three sub-assemblies.

1. Power Supply:

Power supply was fabricated the same way as in transmitter section to provide constant 5V

DC and each of its step was checked the same way.

2. Decoder along with RF receiver:

RF receiver and decoder were connected as per the circuit diagram. The output voltages at

both lower data pins were checked using CRO, if the voltages are found to be same as the

voltages there at encoder. A red LED was connected at VT (Valid Transmission) to get to

know it transmission is occurring between transmitter and receiver. Output voltages of bothdata pins were connected with the input pins of P2 port of microcontroller as shown in the

circuit diagram.

3. Microcontroller along with LCD display:

Input pins of microcontroller P2.7 and P2.6 were checked to receive same voltages as sent by

transmitter using CRO. LCD was connected with microcontroller in the same way as shown

in circuit diagram. Microcontroller with the correct software was burned to display on the

LCD whether the situation of both sensors is normal or abnormal. It was made sure that

display matched the conditions of both sensors accurately and it also changes as soon the

case at sensors changes.

3.2 Engineering Design:

All the components were placed and soldered in a systematic matter, which creates no

confusion and also appeals to eyes. Soldering of components was done neatly.

Cabinets for both transmitter and receiver were designed as shown above in mechanical

subassemblies and made with correct precision of dimensions. PCBs in both transmitter and

receiver were placed on the bottom surface. Small gap was created between surface of

cabinet and PCB using a strip which covered all boundaries of PCB. Tags were used atplaces to connect antennas over the cabinet. Two pins and three pins connectors were used to

take out sensors, leds, switch, and LCD over the surface of cabinet.

Cabinets were permanently enclosed from all sides only the upper surface was screwed so

that it is removable.

18


19/45

Chapter 4

FLOW DIAGRAM

4.1 Flow Chart:

19


20/45

20

StartCheck if P1.4 =0 and P1.7=0Display CONC. ZERO

NO PROBLEM

Check if P1.4 =0 and P1.7=1Display CONC. LOW

BE ALERT

Check if P1.4 =1 and P1.7=1Display " CONC. HIGH"

" DANGER ...RUN "

WaitWaitWaitInitialize P1.4 and P1.7 as input pins and initialize the

LCD


21/45

YES

NO

YES

NO

YES

4.2 Description of Flow diagram:

1. First step is to initialize P1.4 and P1.7 as input pins by using sbit command and then

initialize LCD using different commands like to clear LCD, display on, cursor on, defining

cursor movement either left or right, and position of cursor.

21


22/45

2. Now pins P1.4 and P1.7 are checked for their values, if a pin receives voltage less than

0.8 V then it is considered as 0 bit by microcontroller.

3. If a pin receives voltage greater than 2.5V, then it is considered as 1 bit by

microcontroller.

4. Firstly both pins are checked if they have 0 bit, if condition is satisfied then

microcontroller sends data to LCD to display gas concentration normal as shown in flowdiagram and waits till next change is observed in value of pins.

5. If condition does not satisfy, then it checks if any of the two pins has bit 1. This is done

one by one. If condition satisfies in any of the two cases then it sends data to LCD to display

accordingly. Again it waits.

6. Next condition is checked if both pins have 1 bit, if it satisfies then LCD displays gas

with high concentration and waits for the next change.

7. Wait state exists till any change is observed in any of the bits, if change is observed it

again moves on to check the four conditions.

8. In this way this infinite loop continues until power supply is disrupted or reset is pressed.

Chapter 5

SOFTWARE

5.1 Program Code:

#include

sfr ldata= 0xA0;

sbit rs= P0^0;

22


23/45

sbit rw= P0^1;

sbit en= P0^2;

sbit sw1= P1^4;

sbit sw2= P1^7;

void lcdcmd(unsigned char);

void lcddata(unsigned char);void delay(unsigned int);

void saferoom();

void alertroom();

void dangerroom();

void main()

{ lcdcmd(0x38);

delay(250);

lcdcmd(0x0E);

delaylcdcmd(250);

if(sw1==0 && sw2==0)

{ saferoom(); // room safe

}

else if(sw1==0 && sw2==1)

{ alertroom(); // concentration low and alert

}

else if(sw1==1 && sw2==1){ dangerroom(); // comncentration high and run

}

}

void lcdcmd(unsigned char value)

{ ldata=value;

rs=0;

rw=0;

en=1;delay(1);

en=0;

return;

}

23


24/45

void lcddata(unsigned char value)

{ ldata=value;

rs=1;

rw=0;

en=1;

delay(1);en=0;

return;

}

void delay(unsigned int value)

{ unsigned int i,j;

for(i=0;i


25/45

unsigned int i;

lcdcmd(0x01); //for clear screen

delay(250);

lcdcmd(0x80);

for(i=0;i


26/45

:10026D0050524F424C454D0020434F4E432E204C93

:10027D004F570020424520414C4552540020434FDA

:10028D004E432E2048494748002044414E47455291

:09029D00202E2E2E52554E200099

:1002A6007F381203047FFA7E001202D97F0E1203F2

:1002B600042094082097051201EF80092094063047:0F02C60097031201773094063097031200F92244

:0B02F9007D007BFF7E001200D37F0120

:100304008FA0C280C281D2827F017E001202D9C234

:02031400822243

:050316002521F8E6FFBF

:10031B008FA0D280C281D2827F017E001202D9C20D

:02032B0082222C

:0402D5007F027E0026

:1002D900E4FDFCC3ED9FEC9E5015E4FBFA0BBB005B

:0F02E900010ABA04F8BBFBF50DBD00010C80E45F

:0102F80022E3

:1001EF0078087C007D007BFF7A02795D7E007F0CB2

:1001FF001200D378147C007A0279697F0C1202F90D

:10020F007FFA7E001202D97F80120304E4F520F5F5

:10021F002174081203161202D50521E5217002057B

:10022F0020C3940CE520940040E77FC0120304E440

:10023F00F520F52174141203161202D50521E521BC

:0D024F0070020520C3940CE520940040E7E8

:01025C00227F

:1001770078087C007D007BFF7A0279757E007F0B13

:100187001200D378137C007A0279807F0A1202F971

:100197007FFA7E001202D97F80120304E4F51DF571

:1001A7001E7408251EF8E6FF12031B1202D5051E52

:1001B700E51E7002051DC3940BE51D940040E27F08

:1001C700C0120304E4F51DF51E7413251EF8E6FF9F

:1001D70012031B1202D5051EE51E7002051DC394EE

:0701E7000AE51D940040E24F

:0101EE0022EE

:1000F90078087C007D007BFF7A02798A7E007F0C7C

:100109001200D378147C007D007BFF7A0279967EF9

:10011900007F101202FF7FFA7E001202D97F80123F

:100129000304E4F524F52574082525F8E6FF1203F0

:100139001B1202D50525E52570020524C3940CE59B

:1001490024940040E27FC0120304E4F524F52574E9

:10015900142525F8E6FF12031B1202D50525E5250E

:0D01690070020524C3940FE524940040E2C9

26


27/45

:010176002266

:10000300E709F608DFFA8046E709F208DFFA803EDF

:1000130088828C83E709F0A3DFFA8032E309F608CC

:10002300DFFA8078E309F208DFFA807088828C8334

:10003300E309F0A3DFFA806489828A83E0A3F608E8

:10004300DFFA805889828A83E0A3F208DFFA804CC2:1000530080D280FA80C680D4806980F28033801099

:1000630080A680EA809A80A880DA80E280CA803302

:1000730089828A83ECFAE493A3C8C582C8CCC5837A

:10008300CCF0A3C8C582C8CCC583CCDFE9DEE7804A

:100093000D89828A83E493A3F608DFF9ECFAA9F0C9

:1000A300EDFB2289828A83ECFAE0A3C8C582C8CC1F

:1000B300C583CCF0A3C8C582C8CCC583CCDFEADE38

:1000C300E880DB89828A83E493A3F208DFF980CC9A

:1000D30088F0EF60010E4E60C388F0ED2402B40493

:1000E3000050B9F582EB2402B4040050AF2323453A

:0600F3008223900053730C

:00000001FF

Chapter 6SYSTEM INTEGRATION

6.1 Downloading the program:

6.1.1 Flow Chart to check correctness of code:

YES

27

Software is written in Keil editor

Assembler assembles the code

Check if error

Debugger shows

the error

Analysis is done


28/45

NO

NO

YES

6.1.2 Procedure for downloading the program:

1. Software topwin should be installed on your computer and you should have the

microcontroller burner device.

2. Connect the device with your computer via USB port.

3. Wait to see green light glowing to know if device is ready.

4. Insert your microcontroller in the slots given, looking at the proper orientation of IC pins.

5. Double click on the software trap burn.

6. Select the option Select device from its tool bar.

7. A menu will appear showing names of microcontroller.

8. Select the microcontroller you are going to burn. In our case we selected AT89C51.9. Another dialog box will appear if you want to burn the hex file by 00, or by FF. Take

default settings (by FF).

10. Select the option Choose hex file from tool bar.

11. Open the location where you have stored the hex file and select it

12. Click on the option Burn given on the main screen.

13. Wait till the burning procedure completes.

28

Generate Hex file

Make circuit diagram in Proteus software

Download hex file in microcontroller

Simulate the circuit

Check if getting desired output

Download the hex code into microcontroller through programmer

Check circuit diagram

and code for logic

errors


29/45

14. Now your microcontroller is ready to use.

15. Detach the device from USB and turn off the computer.

6.1 Testing of Project:

1. Project was assembled in two parts transmitter and receiver and testing was done for the

range, DC conditions and Oscillations.

2. Transmitter was made immobile by fixing its position. Receiver was made mobile by

connecting the supply via battery.

3. Firstly receiver was located two meters away from receiver and display was checked by

LCD for all four conditions. It worked.

4. Now we kept on increasing distance between transmitter and receiver and checked the

display for correct output.

5. Valid transmission (VT) at receiver was also blinking continuously.6. After 13 meters we observed that display output was not changing with subsequent

change in sensor conditions. VT also stopped blinking.

7. Thus we got to know that our project was working well within 13 meters of distance.

Chapter 7

PROJECT EVALUATION

7.1 Results & Conclusions:After the successful completion of the hardware of the project it was tested and observations

were taken as stated below.

7.1.1 Observation:

1. The range of transmission between transmitter and receiver was found to be 13 meters.

2. Transmitter section

a) Input voltage of LM7805: 9V

b) Output Voltage of LM7805: 5.04V

c) Vcc of HT12E: 5.04Vd) Vcc of RF transmitter (TWS-434A): 5.03V

e) Vcc of both Comparators (LM358): 5.03V

f) Output Voltage of comparator1 when temperature 40: 3.54V

h) Output voltage of comparator2 when dark : 0V

i) Output voltage of comparator2 when light : 3.54V

29


30/45

1. Receiver section

a) Input voltage of LM7805: 7.4V

b) Output voltage of LM7805: 4.9V

c) Vcc of HT12D: 4.9V

d) Vcc of RF receiver (RWS-434A): 4.8Ve) Input voltage of AT89C51: 5.01V

f) Voltage at pin P2.0 when temp >40: 3.2V

g) Voltage at pin P2.0 when temp


31/45

4. Trim Pot after connection with comparator got damaged due to its improper handling as

screw was not screwed slowly. Thus resistance values were not changing on rotating the

screw. It was detected using multimeter and replaced later.

5. There was mismatching in the pins used for RS, R/W, EN as used in the hardware and

written in the software. There was nothing displayed on LCD. Error was detected by cross

checking both hardware and software connections and corrected by writing correct softwareagain.

6. Pins of P2 port which were connected to decoder were incorrectly connected. Instead of

using P2.0 and P2.1, pins P2.7 and P2.6 were connected. Thus again there was a

mismatching between software and hardware. It was detected by checking all connections

again and corrected.

Chapter 8

ANNEXURES

8.1 Datasheets:

8.1.1Encoder (HT12E):

8.1.1.1 Features:

1. Operating voltage- 2.4V~12V for the HT12E2. Low power and high noise immunity CMOS technology3. Low standby current: 0.1_A (typ.) at VDD=5V4. Minimum transmission word - Four words for the HT12E5. Built-in oscillator needs only 5% resistor6. Data code has positive polarity7. Minimal external components8. HT12E: 18-pin DIP/20-pin SOP package.

8.1.1.2 Absolute Maximum Ratings

1. Supply Voltage (HT12E) ..............._0.3V to 13V

31


32/45

2. Input Voltage....................VSS_0.3 to VDD+0.3V

3. Storage Temperature................._50_C to 125_C

4. Operating Temperature..............._20_C to 75_C

56

7

8

8.1

8.1.1

8.1.1.1

8.1.1.2

8.1.1.3 Pin Diagram

Figure 8.1.1.3.1 Pin Diagram of HT12E

5

6

7

8

8.1

8.1.1

8.1.1.4 Electrical Characteristics

32


33/45

Table 8.1.1.4.1 Electrical characteristics of HT12E

8.1.1.5

Supply

Voltage Vs

Oscillator

Frequency

Graph

33


34/45

Figure 8.1.1.5.1 Supply Voltage Vs Oscillator Frequency Graph for HT12E

8.1.2. Decoder (HT12D):

8.1.2.1. Features:

1. Operating voltage: 2.4V~12V

2. Low power and high noise immunity CMOS technology

3. Low standby current

4. Capable of decoding 12 bits of information5. Binary address setting

6. Received codes are checked 3 times7. Address/Data number combination - HT12D: 8 address bits and 4 data bits8. Built-in oscillator needs only 5% resistor9. Valid transmission indicator10. Easy interface with an RF or an infrared transmission medium11. Minimal external components12. Pair with Holtek_s 212 series of encoders13. 18-pin DIP, 20-pin SOP package .

8.1.2.2. Absolute Maximum Rating:

1. Supply Voltage .........................................._0.3V to 13V

2. Storage Temperature ............................_50_C to 125_C

3. Input Voltage ................................VSS_0.3 to VDD+0.3V

4. Operating Temperature..........................._20_C to 75_C

8.1.2.3 Pin Diagram

34


35/45

Figure 8.1.2.3.1 Pin

Diagram of HT12D

8.1.2.4. Electrical Characteristics:

Table

8.1.2.4.1 Various parameter table for HT12E

8.1.2.5 Supply Voltage Vs Oscillator frequency Graph

35


36/45

Figure 8.1.2.5.1: Graph between oscillator frequency and supply voltage(Vdd)

8.1.1 TWS 434 (RF TRANSMITTER)

8.1.2.1 Pin Diagram

Figure 8.1.2.1.1: pin out of RF Transmitter


36


37/45

Table 8.1.2.2.1: Various Parameters Of RF transmitter

8.1.2 RWS-434 (RF RECEIVER)

8.1.3.1 Pin Diagram

Figure 8.1.3.1.1: Pin out of RF Receiver


37


38/45

Table 8.1.3.2.1: Various Parameters Of RF Receiver

8.1.5 VOLTAGE REGULATOR (LM7805)

8.1.5.1 Features

1. Output Current up to 1A2. Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V3. Thermal Overload Protection4. Short Circuit Protection5. Output Transistor Safe Operating Area Protection


38


39/45

8.1.5.3 Pin Diagram

Figure 8.1.5.3.1:Pin Diagram of Voltage Regulator 7805


Table 8.1.5.4.1: Various Parameters Of 780

1.1.6LM324:

8.1.6.1 Features:

1. internally frequency compensated

39


40/45

2. n large dc voltage gain: 100db3. n wide bandwidth (unity gain): 1.1mhz4. (temperature compensated)5. n very low supply current/op (500a)6. essentially independent of supply7. voltage8. n low input bias current: 20na9. (temperature compensated)10. n low input offset voltage: 2mv11. n low input offset current: 2na12. n input common-mode voltage range13. includes ground14. n differential input voltage range15. equal to the power supply voltage16. n large output voltage swing

8.1.6.2 Pin Diagram

Figure 8.1.6.2.1: Pin Out of LM324[4]

8.1.6.3 Electrical Characteristics:

40


41/45

Table 8.1.6.3.1: Various parameters of Comparator IC LM324[4]

1.1.6AT89C51:

8.1.7.1 Features:1. Compatible with MCS-51 Products2. 4K Bytes of In-System Reprogrammable Flash Memory3. Endurance: 1,000 Write/Erase Cycles4. Fully Static Operation: 0 Hz to 24 MHz5. Three-level Program Memory Lock6. 128 x 8-bit Internal RAM7. 32 Programmable I/O Lines8. Two 16-bit Timer/Counters

9. Six Interrupt Sources10. Programmable Serial Channel11. Low-power Idle and Power-down Modes

1.1.7.2Absolute Maximum Ratings:

41


42/45

Table 8.1.7.2.1:Required Characteristics of AT89C51

8.1.7.3 Pin Diagram:

Figure 8.1.7.3.1:Pin Out Of Microcontroller AT89C51[1]

42


43/45


Table 8.1.7.4.1: Various Parameters of Microcontroller 89C51[1]

1.1.6LCD JHD 162A:

1.1.6.1 Features

1. 5 x 8 dots with cursor

2. Built-in controller (KS 0066 or Equivalent)

3. + 5V power supply (Also available for + 3V)

4. 1/16 duty cycle

5. B/L to be driven by pin 1, pin 2 or pin 15, pin 16 or A.K (LED).

6. N.V. optional for + 3V power supply[1]


43


44/45

Table 8.1.8.2.1: Required Characteristics of LCD JHD 162A[1]

1.1.6.2 Pin Diagram

Figure 8.1.8.3.1 : LCD JHD 162A Pin Out


Table 8.1.8.4.1 : Various Characteristics of LCD JHD 162A

44


45/45

References:

1. Muhammad Ali Mazidi, Janice Gillispie Mazidi, and Rolin D. McKinlay 8051

Microcontroller and Embedded Systems Edition 2008, pp 75 80, 299 - 307.

2. Jacob Millman and Christos C. Halkias Integrated Electronics Edition 1991, pp 501 -

504.

3. J.B. Gupta Electronic Devices & Circuits Edition 2009, page no.215-220

4. Ramakant A. Gayakwad OP AMPs & Linear integrated CircuitsEdition 2008Page no. 358-370.

----------------- X ------------------

Documents

Final Report Theory(System Integrtion and Refrences