INTELLIGENT SYSTEM FOR TOXIC GAS DETECTION USING GSM

TECHNOLOGY

GUIDED BY

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SUBMITTED BY

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Objective

The aim of this project is designing a microcontroller based Toxic gas detector using GAS sensor and human detection using PIR sensor.

Abstract

The detection unit reaches the maximum temperature level and it detects any Toxic gas leakage, it checks any person entering the protected area through PIR sensor, it sends SMS to the user through the GSM modem.

Literature review

[1]. Methane and Carbon Monoxide Gas Detection system based on semiconductor sensor

Cordos, E. Ferenczi, L. Cadar,, S. Pitl, G. Aciu, A. Ghita, A.Automation, Quality and Testing, Robotics, 2006 IEEE International Conference on Volume 2, May 2006 Page:208 – 211.

[2]. Detection of toxic gases by a tin oxide multisensor

Baluk, S. Aleixandre, M. Fernandez, M.J. Ares, L.Garcia, M. Santos, IEEE Volume 2, Issue 5, Oct 2002 Page: 387 – 393.

AT89S51 Microcontroller

• The Micro-controller AT89S51 has many

prominent features suitable for such interfacing

and controlling applications.

• They are also suitable for serial port interfacing

which is very much needed for data transfer.

Block diagram

AT89S51

GSM Modem

RS232

PIR Sensor

Power Supply

Gas Detection

AMP Unit

MAX232

Hardware requirements

• Power supply unit.• AT89S51 Microcontroller.• Sensors.

GAS Sensor. PIR Sensor.

• Amplifier unit.• Alarm unit.• MAX232.• RS232.• GSM Modem.

Software requirements

• Keil C compiler.

• Orcad circuit design.

• Embedded C Programming.

Power supply circuit diagram

VCC

D3

5V1

D2 1N400712

- +

D1

DB106

1

2

3

4U3

LM7805C/TO2201 3

2

IN OUT

GN

D

C9

470uF/25V C10

100

uF/1

6V

C110.1uF

D4

LED

R1

330E

JP8

9V DC

121

2

Features of AT89S51

• 4K Bytes of In-System Programmable (ISP) • Fully Static Operation: 0 Hz to 33 MHz.• Three-level Program Memory Lock.• 128 x 8-bit Internal RAM.• Two 16-bit Timer/Counters.• Six Interrupt Sources.• Low-power Idle and Power-down Modes.• Watchdog Timer , Dual Data Pointer.

Microcontroller circuit diagram

VCC

VCC

P0_0P0_1P0_2P0_3P0_4P0_5P0_6P0_7P1_7

P1_6

P1_1P1_0

P1_3P1_2

P1_5P1_4

P3_3

P3_0

P3_4

P3_7

P3_5

P3_2

P3_6

P3_1

P2_4

P2_2

P2_7

P2_1

P2_5

P2_3

P2_6

P2_0

R28K2

C2 10

uF

U1

AT89S51

9

1819

20

293031

40

12345678

2122232425262728

1011121314151617

3938373635343332

RST

XTAL2XTAL1

GN

D

PSENALE/PROG

EA/VPP

VC

CP1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7

P2.0/A8P2.1/A9

P2.2/A10P2.3/A11P2.4/A12P2.5/A13P2.6/A14P2.7/A15

P3.0/RXDP3.1/TXDP3.2/INTOP3.3/INT1P3.4/TOP3.5/T1P3.6/WRP3.7/RD

P0.0/AD0P0.1/AD1P0.2/AD2P0.3/AD3P0.4/AD4P0.5/AD5P0.6/AD6P0.7/AD7

X111.0592MHz

C333PF

C433PF

C1

0.1uF

RS

T

Microcontroller Pin Description

• I/O port pinsFour ports are: P0, P1, P2, and P3.Each port uses 8 pins.All I/O pins are bi-directional.

• P1, P2, and P3 have internal pull-up resisters.P1, P2, and P3 are not open drain.

• P0 has no internal pull-up resistors and does not connect to Vcc inside the AT89S51.

• All the ports upon RESET are configured as output.

RST （ pin 9 ）： reset• It is an input pin and is active high （ normally

low ） .• The high pulse must be high at least 2 machine

cycles.• It is a power-on reset.

/EA （ pin 31 ）： external access• The /EA pin is connected to GND to indicate

the code is stored externally.• /PSEN ＆ ALE are used for external ROM.• For AT89S51, /EA pin is connected to Vcc.• It is an active low pin.

/PSEN （ pin 29 ）• This is an output pin and is connected to the OE pin of the ROM.

ALE （ pin 30 ）• AT89S51 port 0 provides both address and data.• The ALE pin is used for de-multiplexing the address and data.

XTAL1 (pin 19 ) • Input to the inverting oscillator amplifier.

XTAL2 (pin 18 ) • Output from the inverting oscillator amplifier.

MQ-5 GAS SENSOR

Features

• Sensitivity: 100ppm to 3000ppm.

• Circuit voltage: 3V to 15V DC.

• Dimension (D x H): 19 x 17mm.

• Heater power consumption: 750mW.

• Temperature range: -20deg. C to +40deg. C.

Advantages

• High sensitivity to LPG, natural and town gas.

• Fast response.

• Stable and long life.

• Simple drive circuit.

LM324-D Amplifier IC

PIR SENSOR

• Passive Infrared Sensor (PIR sensor) is an electronic device which measures infrared light radiating from objects in its field of view.

• PIRs are often used in the construction of PIR- based motion detectors.

• Apparent motion is detected when an infrared source with one temperature, such as a human, passes in front of an infrared source with another temperature, such as a wall.

Features

• Excellent RFI/EMI immunity.

• Delay time is adjustable.

• Simple in structure.

• Intelligent signal processing circuit.

Specifications

• Power Supply : 110V~240V AC

• Dimension : 33x82x86mm(wxdxh)

• Maximum load : 10A

• Working temperature: -20oC~60oC.

• Detection range : 12mts.

• Horizontal/Vertical

detection angle : 1600/3600

Serial port interface

TXD

RXD

VCC

C7

10uF

C510uF

C8 10uF

P1

SERIAL PORT

594837261C6

10uF

U2

MAX-232

138

1110

1345

26

129147

1615

R1INR2INT1INT2IN

C+C1-C2+C2-

V+

V-

R1OUTR2OUTT1OUTT2OUT

VC

CG

ND

RS-232

• In RS-232, the data is sent as a time series of bits.

• Both asynchronous and synchronous transmissions are supported by the standard.

• In addition to the data circuits used to manage the connection between the DTE and DCE, each data or control circuit operates only in one direction.

• It can operate in full duplex manner.

GSM MODEM

• A GSM modem is a wireless modem that works with a GSM wireless network.

• A wireless modem behaves like a dial-up modem.• The main difference between them is that a dial-up

modem sends and receives data through a fixed telephone line while a wireless modem sends and receives data through radio waves.

GSM MODEM

GSM Technology

• Used by more than 214 countries.

• Operating bands: 900MHz and 1800MHz.

• Data transfer speed: 9.6Kbps roaming.

• Supports SMS service.

• GSM modem receives and transmits SMS.

Detailed project circuit diagram

VCC

VCC

VCC

VCC

+9V

VCC

VCC

VCC

VCC

TXD1

RXD0

RST

TXD0

P0_0

P2_2

P0_0

RXD1

TXD0

PIR IN

RXD0

U1

MAX232

138

1110

1

3

4

5

2

6

129

147

16

15

R1INR2IN

T1INT2IN

C+

C1-

C2+

C2-

V+

V-

R1OUTR2OUT

T1OUTT2OUTV

CC

GN

D

C

R1

SIP

9 1

0k

123456789

C2

0.1uF

R4

1k

C1

10uF

C6

10uF

P1

SE

RIA

L P

OR

T

594837261

C833PF

R7

RE

SIST

OR

VA

R

13

2

C3

10uF

X1

11.0592MHz

Q1BC547

12

3

C4

10uF

R1 1K

LS1

BUZZER

1

2

SW

1R

ST

C5

10uF

U2

AT89S51

9

1819

20

293031

40

12345678

2122232425262728

1011121314151617

3938373635343332

RST

XTAL2XTAL1

GN

D

PSENALE/PROG

EA/VPP

VC

CP1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7

P2.0/A8P2.1/A9

P2.2/A10P2.3/A11P2.4/A12P2.5/A13P2.6/A14P2.7/A15

P3.0/RXDP3.1/TXDP3.2/INTOP3.3/INT1P3.4/TOP3.5/T1P3.6/WRP3.7/RD

P0.0/AD0P0.1/AD1P0.2/AD2P0.3/AD3P0.4/AD4P0.5/AD5P0.6/AD6P0.7/AD7

Q1

BC547

12

3

K1

5V

34

5

68

712

C733PF

R2

8K2

gas sensor

ALARM CIRCUITPORT-GSM MODEM

GND

PIR sensor

+

-

3

21

411

FlowchartStart

Enable Serial Interrupt and Global Interrupt

EA, ES, P1, P0, P2, alarm, pir, gas

Gas==1

serial port initialization

Delay for 1Min

Loop forever

Call Gas Functionj=0

A

B

send[j]!='\0'

SBUF = send[j++]

Delay for 1Min

send[j]=='\0'

Delay for 1Min

SBUF = 0x0D

Delay for 1Min

k=0

message2[k]!='\0'

B

C D

C

SBUF = 0x1A

Delay for 1Min

gas=0

pir==0

Call pir_send()

pir=1, x=0

A

SBUF = message2[k++];

Delay for 1Min

D

Snapshot of the project

Advantages

• Fast response.

• Accurate detection.

Applications

For detection of Toxic gas leakage in

• Industry.

• Automobiles.

• Hospitals.

• Home.

Future scope

• High definition web camera can be interfaced.

• Temperature sensor can be added with the existing module.

• Controlling of the remote devices can be done.

ConclusionThe project “Intelligent system for toxic

gas detection using GSM technology” has been designed and fabricated into a demo unit and tested and found successful. For the demo purpose, the system detects butane and propane gases. Thus, the system can detect toxic gases and sends SMS to the user. It is also designed to detect human presence by using PIR sensor.

By implementing this project “Toxic Gas” leakage can be detected and human lives can be saved.

Thank you