Types Of Sensor That Being Used For Experiment

       Before we are using MQ-4 for this project we run some experiment to some sensor to determine which sensor is more suitable for our project and for ours circuit

This is the first sensor that we used for the experiment which is MQ-137

 

This is the second sensor that we are using that is MQ-2

The third sensor that we used is MQ-138

The last sensor that we being use is MQ-4

After getting the result we decide to used MQ-4 for ours project.This is because the LPG Gas Sensor (MQ4), ideal sensor for use to detect the presence of a dangerous Liquefied petroleum gas (LPG) and it has high sensitivity to propane, butane, isobutene, natural gas. The sensor can also be used to detect combustible gases, especially methane. This sensor has a high sensitivity and fast response time.

Making A Simple PCB Board For The Sensor

Today we'll make a PCB for this circuit. The component the use is PCB maker pen, PCB board, etching liquid and thinner.

Im doing by my self to make a line on PCB board.This is to lower the cost to buy a new PCB board and learn how to make the PCB board without doing it at lab.

Make a MQ 4 Gas Sensor at PCB

Here the step :

1st : Clean the PCB board with soap using spongy scruber and leaveit until dry

2nd : Ligthly sketch the circuit diagram by using pencil for clear sketch before using maker pen

3rd : Then sketch by using maker pen or PCB maker

4th : Use any sharper things and then scale to remove extra lines

5th: Submerge PCB into etching solution

                                                 

6th: After perfect etching, wash the PCB by using water

7th : Using thinner to remove maker lines on the PCB board

8th: Finally we will get the real line at PCB and ready to drill.!!!

The PCB board is ready to use.

Circuit Diagram For Wireless Gas Leakage Detector Alarm

Note : Red LED will flash a few seconds after the switch is on and the green LED goes on to indicate the sensor has active. Then try to detect the sensor using LPG or smoke etc. When the sensor would detected gases, the relay will act as a switching and transmit go through door bell alarm / alarm system.

Research on type of gases

  As being mentioned before the specified gas that can be detect by this project is LPG gas so i'm doing some research on the LPG gas. It is liquid petroleum gas or simply propane or butane, is a flammable mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. When specifically used as a vehicle fuel it is often referred to as auto gas. Here are some product that use LPG gas:

  This gas is heavier than air, when it leaks from a cylinder it flows along floor and tends to settle in low spots such as a basement. This can cause fire or suffocation if not dealt with. Here is a circuit that detects the leakage of LPG gas and alerts the user through audio-visual indications.

          This LPG Gas Sensor (MQ4), ideal sensor for use to detect the presence of a dangerous Liquefied petroleum gas (LPG) and it has high sensitivity to propane, butane, isobutene, natural gas. The sensor can also be used to detect combustible gases, especially methane. This circuit can detect leakages in your Home, car or in a service station, storage tank environment. This unit can be easily implemented to industrial level by upgrading its ranges.

        This project is designed to detect the LPG from 200parts per million (PPM) to 10,000 PPM. Whenever there is LPG concentration of 1000 ppm (parts per million) in the area, the OUT pin of the sensor module goes high. This signal drives timer IC 555, which is wired as an astable multivibrator. The multi vibrator basically works as a tone generator. A buzzer is connected to produce audible alert signal.

        

Introduction of wireless gas leakage detector alarm

The project that i being doing for my final year project is wireless gas leakage detector alarm. Wireless gas leakage alarm is a alarm that being used to detect gas leakage in industry,house or office.For my project the specified gas can be detected is LPG gas which is liquefied petroleum gas.This is because the sensor that being used for this project is MQ-4.This project is used to detect a gas leak and interface with a control system so a process can be automatically shut down. For this project i'm using alarm to be the output for the project,this is to give a warning for the employees or public people to alert to the leak of gas and giving them the opportunity to leave the area. This type of device is important because the gas can that can be harmful to organic life, such as humans or animals.

   

          This project is using direct supply for both Tx and Rx.  When dangerous levels of gas vapors are detected. As detectors measure a gas concentration, the sensor responds to a calibration gas, which serves as the reference point or scale. As a sensor’s detection exceeds a preset alarm level, the alarm or signal will be activated. As units, gas detectors are produced as portable or stationary devices. Originally, detectors were produced to detect a single gas, but modern units may detect several toxic or combustible gases, or even a combination of both types.

          

Types

There are several types of the gas leakage detector as shown below:

1.)Electrochemical Detectors

Electrochemical gas detectors work by allowing gases to diffuse through a porous membrane to an electrode where it is either oxidized or reduced. 

2.)Infrared Point Detectors

Infrared (IR) point sensors use radiation passing through a volume of gas to detect leaks. Energy from the radiation is absorbed as it passes through the gas at certain wavelengths. 

3.)Infrared Imaging Detectors

Infrared point sensors are active measurement systems, in that they typically measure the absorption of a gas by passing it through a laser-illuminated chamber and measuring the change in transmitted signal. 

4.)Semiconductor Detectors

Semiconductor sensors detect gases by a chemical reaction that takes place when the gas comes in contact with the sensor. 

5.)Ultrasonic Detectors

Ultrasonic gas detectors use acoustic sensors to detect changes in the background noise of its environment. Since most gas leaks occur in the ultrasonic range of 25 kHz to 10 MHz, the sensors are able to easily distinguish these frequencies from background noise which occurs in the audible range of 20 Hz to 20 kHz.

6.)Holographic Detectors

Holographic gas sensors use light reflection to detect changes in a polymer film matrix containing a hologram. 

For this project i'm using electrochemical detectors by using MQ-4 sensor.