According To Specific Gravity Of Natural Gas, Its Specific Gravity Is Lighter Than The Specific Gravity Of Air, And So Natural Gas Suspends On The Ceiling. Therefore, The Alarm Should Be Installed in the Small Area Which is 0.3~1.2 Meter Less than The Ceiling and within Radii 1.5 Meter far From Gas Leakage.
Liquid petroleum Gas: It's Specific Gravity Is Higher than Air, So It Sinks down on the Bottom. Therefore, the alarm should be installed in the area that is 0.3~ 1.2 meters far from ground and within radii 1.5 meter far from gas leakage.
1.1 OBJECTIVE OF THE PROJECT: -
The aim of the project is to save The People from Gas Leakage Accident used in places like Canteen, Houses, Hotels, & Restaurants, as well as in the various industries where Gas is very important for the people who come to Lunch & dinner as well as processes involved in the manufacturing and service industry.
According to the Gas Leakage Detector can be Save Lots of Problems. By using this system, we can also adjust the Regulation of the Gas using Mq5 and.
1.2 PRINCIPLE OF OPERATION
I used MQ5 gas sensor with the experimental kit. The sensor detect the gas and pass the variable voltage to pic18f1320 and If the gas level is normal lies between 1.2 volt to 4 volt, I activated two led's and a buzzer in slow mode for early warning then if the gas level goes high then I activated a led and 2 buzzer in fast mode it is for high level of gas so I done it for that.
1.3- System Features:-
Gas Detectors
Type of the various gas detectors:-
Analyzers: Continuous monitoring of toxic gases at ultra low ppb levels directly integrated into life safety systems Fire & Gas: Flame, smoke & gas detectors coupled with sophisticated control solutions for offshore and industrial applications.
Fixed Controller Systems: The control systems behind integrated `plant-wide' fire and gas detection.
Personal Gas Detection: Effective personal protection from gas hazards, when and where it's needed.
Domestic Gas Detectors
we are engaged in the manufacturing of domestic gas detectors. These products are used in homes for detecting gas leaks & avoiding accidents. Easy to install, these wall-hung detectors have an audio-visual alarm that alerts the client when the gas leak concentration reaches a dangerous level. This gives adequate time to take the necessary actions towards avoiding loss of lives and property. Following are some of the salient features of these detectors
GAS DETECTOR
Features: Integral concussion-proof boot Continuous LCD shows real-time gas concentration with backlight in low light (auto); in alarm (auto) and on demand
Waterproof IP 66/67 rating up to 3 ft fully submerged Provides 85 dB tone and bright LED indication on alarm (typical) 3-year battery life (9,000 hours) available with internal vibrating alarm Equipped with plug-in, replaceable sensor Simple auto-zero and calibration procedure Peak value displayed on command (in %) TWA (time weighted average) values are recorded and displayed.
Mutli Gas Detection
we have the most advanced handheld volatile organic compound (VOC) detector on the market. Its Photo ionization Detector's (PID) extended range of 0 to 15,000 ppm makes it an ideal instrument for applications from industrial hygiene, to leak and HazMat detection.
CHAPTER 2
DESCRIPTION OF THE PROJECT
2.DESCRIPTION OF THE PROJECT
LPG Gas Sensor (MQ5)
It Extensively Used In Homes, Cars, Service Stations and Storage Tank. This Sensor Can Be Easily Installed Into An Alarm Unit. The Equipment Provides Visual Indication Of The Combustible Gas or LPG Concentration. It Can Be Iso-butane, Propane, LNG and Cigarette Smoke. We Hold Expertise in Offering Wireless Gas Leak Detectors for Home security systems. Given below are few highlighting features of our products-
Improvement of Products & Its Features Is a Continuous Process.
MQ-5 Semiconductor Sensor for Combustible Gas
Sensitive material of MQ-5 gas sensor is SnO2, which with lower conductivity in clean air. When the
Target combustible gas exist, the sensor's conductivity is higher along with the gas concentration rising.
MQ-5 gas sensor has high sensitivity to Methane, Propane and Butane, and could be used to detect
both Methane and Propane. The sensor could be used to detect different combustible gas especially
Methane, it is with low cost and suitable for different application.
Character Configuration
* Good sensitivity to Combustible gas in wide range
* High sensitivity to Methane, Butane and Propane
* Long life and low cost
* Simple drive circuit
Application
* Domestic gas leakage detector
* Industrial Combustible gas detector
* Portable gas detector
Sensitivity Characteristics
Influence of Temperature/Humidity
Structure and configuration
Structure and configuration of MQ-5 gas sensor is shown as Fig. 3, sensor composed by micro AL2O3 ceramic tube, Tin Dioxide (SnO2) sensitive layer,
Measuring electrode and heater are fixed into a crust made by plastic and stainless steel net. The heater provides necessary work conditions for work of sensitive components. The enveloped MQ-4 has 6 pin, 4 of them are used to fetch signals, and other 2 are used for providing heating current.
Notification
1 Following conditions must be prohibited
1.1 Exposed to organic silicon steam
Organic silicon steam cause sensors invalid, sensors must be avoid exposing to silicon bond, Fixtures, silicon latex, putty or plastic contain silicon environment.
1.2 High Corrosive gas
if the sensors exposed to high concentration corrosive gas (such as H2Sz, SOX, Cl2, HCl etc), it will not only result in corrosion of sensors structure, also it cause sincere sensitivity attenuation.
1.3 Alkali, Alkali metals salt, halogen pollution the sensors performance will be changed badly if sensors be sprayed polluted by alkali metals salt
especially brine, or be exposed to halogen such as fluorine.
1.4 Touch water
Sensitivity of the sensors will be reduced when spattered or dipped in water.
1.5 Freezing
Do avoid icing on sensor' surface, otherwise sensor would lose sensitivity.
1.6 Applied voltage higher
applied voltage on sensor should not be higher than stipulated value, otherwise it cause down-line or heater damaged, and bring on sensors' sensitivity characteristic changed badly.
1.7 Voltage on wrong pins
For 6 pins sensor, if apply voltage on 1/3 pins or 4/6 pins, it will make lead broken, and without signal when apply on 2/4 pins.
2 Following conditions must be avoided
2.1 Water Condensation
Indoor conditions; slight water condensation will affect sensors performance lightly. However, if water Condensation on sensors surface and keep a certain period, sensor' sensitivity will be decreased.
2.2 Used in high gas concentration
No matter the sensor is electrified or not, if long time placed in high gas concentration, if will affect sensors characteristic.
2.3 Long time storage
The sensors resistance produce reversible drift if it's stored for long time without electrify, this drift is related with storage conditions. Sensors should be stored in airproof without silicone gel bag with clean air. For the sensors with long time storage but no electrify; they need long aging time for stability before using.
2.4 Long time exposed to adverse environment
No matter the sensors electrified or not, if exposed to adverse environment for long time, such as high humidity, high temperature, or high pollution etc, it will affect the sensors performance badly.
2.5 Vibration
Continual vibration will result in sensors down-lead response then rapture. In transportation or assembling line, pneumatic screwdriver/ultrasonic welding machine can lead this vibration.
2.6 Concussion
if sensors meet strong concussion, it may lead its lead wire disconnected.
2.7 Usage
For sensor, handmade welding is optimal way. If use wave crest welding should meet the following conditions:
2.7.1 Soldering flux: Rosin soldering flux contains least chlorine
2.7.2 Speed: 1-2 Meter/ Minute
2.7.3 Warm-up temperature:100ñ20?
2.7.4 Welding temperature: 250ñ10?
2.7.5 1 time pass wave crest welding machine
If disobey the above using terms, sensors sensitivity will be reduced.
LPG Sensor
LPG level Sensor with Mechanical Reading By Means Of a Gauge Fitted on the Multivalve, Tank Level Indication from Empty to Full Is Shown. The Sensor Transforms The Position Of the Float Into An Electric Signal If Combined With A Switch UnitÿPre-arranged for the purpose.
CNG Sensor With Pressure Gauge
CNG Pressure Sensor With Mechanical Reading By Means Of A Gauge Indicates From Empty To Full Be Shown In Clockwise Direction. It Transforms Tank Pressure In To An Electrical Signal Indicates From 0 to 400 Bars.
Analyzers:
Continuous monitoring of toxic gases at ultra low ppb levels directly integrated into life safety systems Fire & Gas: Flame, smoke & gas detectors coupled with sophisticated control solutions for offshore and industrial applications.
Fixed Controller Systems:
The control system behind integrated `plant-wide' fire and gas detection.
Personal Gas Detection:
Effective personal protection from gas hazards, when and where it's needed.
Simulations
This is for high level gas red led is on in fast mode and two buzzers are on in fast mode (delay 50ms).This is for low level of gas led's green and yellow are on in slow mode (delay 100ms) and a buzzer is on in slow mode (100ms delay)
Circuit Design
Microchip icd2 in circuit debugger this is the device used to feed the programmers into the pic18f1320 please explain a about this also please give some sentence about MPLAB IDE.
CHAPTER 3
HARDWARE DESCRIPTION
HARDWARE DESCRIPTION
what is a PIC Microcontroller?
A PIC Microcontroller Is a Single Integrated Circuit Small Enough To Fit in the Palm Of A Hand. `Traditional' Microprocessor Circuits Contain Four or Five Separate Integrated Circuits - The Microprocessor (CPU) Itself, an EPROM Program Memory Chip, Some RAM Memory and an Input/output Interface. With PIC Microcontrollers All These Functions Are Included Within One Single Package, Making Them Cost Effective And Easy To Use.PIC Microcontrollers Can Be Used As The `Brain' To Control A Large Variety Of Products. In Order To Control Devices, It Is Necessary To Interface Them To The PIC Microcontroller. This Section will help to enable those with limited Electronics Experience to successfully complete these interfacing tasks. Interfacing to the PIC Microcontroller this section explains how to interface many different inputs and output devices to the PIC microcontroller. BASIC code examples are provided for users of the Basic Stamp or PICAXE systems. Explanations of BASIC commands are provided in the Commands section (available separately). The interfacing circuits can also be used with any PIC microcontrollers such as the PIC16F84, although these microcontrollers may require programming in assembler code.
This section is split into four subsections:
Introduction to `standard' interfacing circuits
Output Device Interfacing
Input Device Interfacing
Advanced Component Interfacing
Standard Interfacing Circuits
1. The Standard Transistor Interfacing Circuit
2. Using a Darlington Driver IC
3. The Standard Relay Interfacing Circuit
4. The Standard FET Interfacing Circuit
Output Device Interfacing
1. LED
2. Signal Lamp
3. Buzzer
4. Piezo Sounder & Speakers
5. Solar & DC ("toy") Motors
6. Unipolar Stepper Motor
7. Bipolar Stepper Motor
8. Radio-Control Servo
9. Counter Module
10. Seven Segment Displays
11. Solenoid & Isonic Solenoid Valve
12. Smart Wire / springs
Input Device Interfacing
1. Switches
2. Potentiometers
3. Light Dependant Resistor (LDR)
4. Thermostat
Advanced Component Interfacing
1. Liquid Crystal Display (LCD)
2. Serial Communication with a Computer
The Printed Circuit Board (PCB) Layout
The connections on the PCB should be identical to the circuit diagram, but there is hardly any correlation between the two as the circuit diagram is readable and the PCB layout is functional.PCB layout is performed manually using an Auto router which can help in getting the best results. This is possible because of the design engineers who are the experts in judging the connectivity in circuits. Because most of the auto routed boards are found to be illogical, this often leads to optimistion of the connections in the circuit, which becomes problematic at times at the time of repairing. Historically PCB's are laid out by drawing on papers that is actually is manual routing.
The PCB CAD layout consists of different layers which are colored and gives rise to one image in all. When we use actual size check plots while laying out boards which are itself a great check while laying out the boards. Whereas most other overlays need to be printed out and then enlarged to show the details. The print can be placed in the actual enclosure in relation to the other parts. For quicker check of dimensions we can place the enclosures up against the markings.
We can put a bit effort to change the PCB design. The width of the path is based on current flow, electromagnetic interface, size of the parts enclosed and the space available. The track of the path is a similar trade off which on the other hand moves from one side to the other to avoid any obstacles, but overall aims to find the shortest path between the connected points.
A Rotten Layout
The circuit boards are automatically assembled and tested but still people install and repair them. A Quality design makes difference between a product that is easy to work and the one that is complicated and is not liked. Machine Test Points for ATE nail testing needs plain pads or lands. However some test points are intended to be meant for engineering tests for which proper labeled and circled pads. For a better product we use completely silkscreen overlay on most of the boards. The silkscreen has all the information that assists people to install the product. Apart from PCB the overlay is the chief distinguishing feature.We will label the terminals as: "+12v red" "-power black" "solenoid+" "solenoid-", whereas the competitors will label it as "A1 A2 A3 A4" because they do not have many options and also they are not known to what to attach to the terminals.
For dense surface boards, we need to leave off component values and also sometimes omit component designators. We first try to drop the size of the letters. The silkscreen is the primary method for labeling connectors, replaceable parts ,orientation and even installation notes.
For instance "Remove J2 while replacing battery-observe the battery polarity"). It can also used for backups. (for example "Mount R2 approx 5mm off circuit board due to high temperature") although now we normally put these notes in the BOM.
The PCB's also had to follow some techniques to comply.
Double Sided Laminates
There are two copper tracks on both the sides of the board.
Plated Through Hole
The holes are copper plated forming a circuit between the two sides of PCB.
Different methods of PCB construction:
Conventional:
It has a thickness of 1.6mm with wire components tied on only one side of the PCB.It is easier to debug and repair than surface mount.
Surface Mount Technology:
It is generally smaller than conventional which is more suitable to automated assembly than conventional.
Surface Mount and Conventional mix:
Most of the boards are a mixture of surface mount and conventional PCB's.As technologies require different methods of insertion and soldering which can be disadvantageous.
Double Sided laminate:
A PCB laminate having tracks on both the sides with PTH holes connecting the circuits from both the two sides.
Double Sided Component assembly
Consists of mounting components on both the sides of the component assembly.Genareally a surface mount is mounted on both the sides of the board but sometimes a conventional mount is attached on the reverse of PCB to make the diagram look more uniform.
Multi Layer
It is formed using more than two copper layers which are also called a sandwich construction. The number of layers reflects the cost of the construction. The misllaneous layers may be used to distribute electricity in a more effective manner.
Gold Plated
It requires only thin gold plating which is achieved using an electro less gold.
If thicker gold plating is required it needs an electrolytic process of generation of electricity. This is limited to pads on the edge of a PCB, as an electrolytic plating bar must be attached to the pads and then also removed through the PCB manufacturing process. Gold plating needs nickel plating or else the gold plating underneath may dissolve into copper.
Immersion Silver Plating
An ROH board that is cost effective to gold.
Chip On Board
IC is attached direct to a PCB and the bond wires directly to PCB lands. The chip is covered with a black blob of epoxy.A technique that is most commonly used with a very high volume and cost sensitive application is musical greeting card.
Phenol PCB
It is a cheaper PCB laminating material.
Daughterboard
A type of circuit board which can also be connected to the other circuit board.
Basic Essential Codes
Simple basic examples are provided within each section. The samples are not complete programs but act as the codes that can be used within the main program while using that particular component.
While using the code sample following things must be kept in mind:
Each pin must be set as an input or output before using the code.
If the hardware pins are changed from the one in the circuit diagram, modification of the pin numbers becomes necessary.
Any command can help adjust all the 8 pins in the port.
Variables must be kept independent of one another. If the same variable is used in the code I should be made sure that the two variables do not clash with any other part of the code.
Conclusion
Gas Leakage detective system is very important in terms of leakage protection. It can be used anywhere in a process industry with little modifications as required. The concept ensures flexibility to adapt and exchange as change is often required.
In this project we have studied a complete model using a PIC microcontroller. The programming and interfering of the PIC microcontroller has been implemented. This work includes the study of saving energy.
