Exhibition Day/Industrial Day

    Today is the day for our final project exhibition where we each group will be interview by two lectures that had being selected.And they will asking about the project that we had being done which is wireless gas leakage detector alarm and we must explain with details about the operation for ours project. For ours group, the lectures in charge is Madam Julie and Sir Ghazali

This is we during the Exhibition Day

This is our project ready to be present

In the end, the exhibition goes well and we have finish FYP module for this semester.Here i will like to thanks my fyp partner which is Amirul Aizat bin Iberhim because had being through all the tough day with me to finish this project and here also i dedicated my most respect and thank you to our fyp supervisor that is Prof.Dr.Zulkifli Abdul Kadir Bakti.

We thank you sir because you have guide and teach us almost everything about the project, and you are always there when we are almost lost.

THANK YOU SIR.

Fully Complete Project

    As now after a long hard work the wireless gas leakage detector alarm had being 100% complete,and here i will explain some of the part of the project itself. This is the circuit for the Tx and this circuit using 12V from the adapter.
While to active/on the doorbell circuit it must used an extra supply which is battery.

Gas Sensor Circuit and Transmit ( Tx ) Circuit from wireless doorbell.

Transmitter need to use battery to active the wireless form Tx to Rx

Receiver ( Rx ) as a Alarm Alert 

Receiver ( Tx ) used 2 pin AC supply as a wireless alarm detector

Final 

From left - Box 1 - : Gas sensor that connected with adapter as a transmit wireless

- Box 2 - : Detection alarm as a receiver ( output ) 

Used lighter or any other thing that have LPG gas to active the sensor 

Project Explanation

   This is the mini-project which we have done successfully. This is a Live Real-Time Project designed at low cost with high accuracy. It is easy to implement. This is very much cost effective when compared to other devices in online. This Project is designed to detect the LPG Gas Leakages and to alerts the users through Audio-Visual Indications. This Project is designed to detect the LPG & 4 other Dangerous Gases from a range 200(PPM) to 10,000 PPM. We used MQ-4 gas sensor. Whenever there is LPG concentration of 1000 ppm (parts per million) in the area. A buzzer is connected to produce audible alert signal. This LPG Gas Sensor can be used to make wireless Gas leak detector in home security system .

                                                      Example how the circuit work

                                                     The project had being label

Explanation Of Circuit Working

As this project is using MQ-4 gas sensor as mentioned before,fromr its datasheet, it has high sensitivity to propane, butane, isobutene,LPG and natural gas. The sensor can also be used to detect combustible gases, especially methane. This circuit has been tested with LPG gas and was found to work very fine.

         From the schematic circuit, there have 2 LED which is red and green as a indicator of the circuit. The red LED function as a starter or warm up to make an sensor active. The red LED will blink for a few sec before the LED off and the green LED will turn on that show the sensor already activated and ready to detect any various kind of gases. 
      When the sensor would detected gases, the buzzer will sound a few second and the wireless alarm will sound as a warning to people at the building or factory or etc. 
          Here we use 5v dc relay as a switching to make an alarm activated and IC1 LM324 as a amplifier to the circuit. We also used preset resistor 10k to adjust the sensitivity of the sensor and we use 12V adapter as a supply to the circuit


Let watching this video:

As shown above is how the project function when it detect LPG gas.

Doorbell That Being Modified To Fit With The Original Circuit

As being order before we must modified the doorbell so that it can be connected with our sensor circuit. And this is what we have done, we had remove the switch of the transmit ( Tx ) wireless doorbell.
Then we connect the connection wire of the transmitter wireless doorbell to the output of the gas detection sensor.When the sensor detect gas according to the concentration the relay will switch on and the doorbell circuit will sent a signal to the Rx and alarm will on.After a hard work the doorbell had being successfully combines with the real circuit.  

This is the result that we've combined the gas detector circuit and wireless doorbell transmitter(Tx). 

This is the receiver(Rx) from the wireless doorbell. 

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Type Of Doorbell Used For The Project

Our supervisor had give an order to modified wireless doorbell act as a wireless alarm for the gas sensor. We need to modified this wireless doorbell then connected with gas sensor. Beside our supervisor provide the wireless doorbell. So that we need to do some research to make sure this doorbell can be combine with the original gas sensor circuit.

This is the type of wireless doorbell(real picture)

Circuit Diagram And PCB Layout For The Project

 SCHEMATIC DIAGRAM

PCB TRACK

COMPONENT PLACEMENT

Note : Create a circuit by using Diptrace software to make a PCB track to assemble all the component. 

Experiment Of Different Types Of Sensor

    To choose which sensor is suitable for our project we are ask to do some experiment to determine the sensitivity of each sensor. And here are the thing that we done during the experiment.

This is the circuit for the sensor

                           1.) This is the picture when we are trying to set the voltages of the sensor

                                         

2.)The pictures when we are trying get the reading of the sensor

                                                                               

3.)This were the substances that we used to active the sensor

This is when we are using alcohol 

 

This is when we are using urine to active the sensor

              

Description And Explanation For The Sensors That Being Used

1) MQ 137 Semiconductor Sensor for Ammonia.

 Description : 

          Sensitive material of MQ 137 gas sensor is Sn02 which with lower conductivity in clean air. When the target combustible gas exist, the sensor's conductivity is more higher along with the gas concentration rising. Please use simple electrocircuit , convert change of conductivity to correspond output signal of gas concentration.

          MQ 137 gas sensor has high sensitivity to Ammonia, also to the other organic amine. The sensor could be used to detect different gas which contains Ammonia, it is with low cost and suitable for different application.

Character :

• Good sensitivity to Ammonia
• Long life and low cost
• Simple drive circuit

Application :

• Domestic Ammonia detector
• Industrial Ammonia gas sensor
• Portable gas sensor

Configuration :

Technical Data :

Basic test loop

The figure above is a basic test circuit of the sensor. The sensor need to put 2 voltage, heater voltage ( VH ) and test voltage ( VC ). VH used to supply certified working temperature to the sensor, while VC used to detect voltage ( VRL ) on load resistance ( RL ) whom is in series with sensor. The sensor has light polarity, Vc need DC power. VC and VH could use same power circuit with precondition to assure performance of sensor. In order to make the sensor with better performance, suitable RL value is needed :

Resistance of Sensor ( Rs ) : Rs = ( Vc/VRL - 1 ) x RL

Sensitivity Characteristics :

Figure above shows the typical sensitivity characteristics of the MQ 137, ordinate means resistance ratio of the sensor ( Rs / Ro ), abscissa is concentration of gases. Rs means resistance in different gases, Ro means resistance of sensor in 550ppm ethanol. All test are under standard test conditions.

PS : Sensitivity to smoke is ignite 10pcs cigarettes in 

Influence of Temperature / Humidity :

Figure above shows the typical temperature and humidity characteristic. Ordinate means resistance ratio of the sensor ( Rd / Ro ), Rs means resistance of sensor in 50ppm NH3 under different temperature and humidity.  

Structure and configuration : 

Structure and configuration of MQ 137 gas sensor as shows at figure above, sensor composed by micro AL203 ceramic tube, Tin Dioxide ( Sn02 ) sensitivity layer, measuring electrode and heater are fixed into a crust by plastic and stainless steel net. The heater provides necessary work conditions for sensitive components. The enveloped MQ-4 have 6 pin, 4 of them are used to fetch signals, and other 2 used for providing heating current.

2) MQ 138 Semiconductor Sensor for Organic Steam.

Description : 

         Sensitive material of MQ 137 gas sensor is Sn02 which with lower conductivity in clean air. When the target combustible gas exist, the sensor's conductivity is more higher along with the gas concentration rising. Please use simple electrocircuit , convert change of conductivity to correspond output signal of gas concentration.

          MQ 138 gas sensor has high sensitivity to Toluene, Acetone, Ethanol and Formaldehyde also to the other organic steam. The sensor could be used to detect different organic steam, it is with low cost and suitable for different application.

Character :

• Good sensitivity to Organic Steam
• High sensitivity to Toluene, Acetone and Ethanol
• Long life and low cost
• Simple drive circuit

Application :

• Domestic Organic steam detector
• Industrial Organic steam detector
• Portable gas detector

Configuration :

Technical Data :

Basic test loop

The figure above is a basic test circuit of the sensor. The sensor need to put 2 voltage, heater voltage ( VH ) and test voltage ( VC ). VH used to supply certified working temperature to the sensor, while VC used to detect voltage ( VRL ) on load resistance ( RL ) whom is in series with sensor. The sensor has light polarity, Vc need DC power. VC and VH could use same power circuit with precondition to assure performance of sensor. In order to make the sensor with better performance, suitable RL value is needed :

Resistance of Sensor ( Rs ) : Rs = ( Vc/VRL - 1 ) x RL

Sensitivity Characteristics :

Graph above shows the typical sensitivity characteristics of the MQ 138, ordinate means resistance ratio of the sensor ( Rs / Ro ), abscissa is concentration of gases. Rs means resistance in different gases, Ro means resistance of sensor in 100ppm Toluene. All test are under standard test conditions.

Influence of Temperature / Humidity :

Figure above shows the typical temperature and humidity characteristic. Ordinate means resistance ratio of the sensor ( Rd / Ro ), Rs means resistance of sensor in 100ppm Toluene under different temperature and humidity.  Ro means resistance of the sensor in environment of 100ppm Toluene, 20C/65%RH.

Structure and configuration : 

Structure and configuration of MQ 138 gas sensor as shows at figure above, sensor composed by micro AL203 ceramic tube, Tin Dioxide ( Sn02 ) sensitivity layer, measuring electrode and heater are fixed into a crust made by plastic and stainless steel net. The heater provides necessary work conditions for sensitive components. The enveloped MQ-4 have 6 pin, 4 of them are used to fetch signals, and other 2 used for providing heating current.

3) MQ 2 Semiconductor Sensor for Combustible Gas.

Description :

          Sensitive material of MQ 2 gas sensor is Sn02 which with lower conductivity in clean air. When the target combustible gas exist, the sensor's conductivity is more higher along with the gas concentration rising. Please use simple electrocircuit , convert change of conductivity to correspond output signal of gas concentration.

          MQ 2 gas sensor has high sensitivity to LPG, Propane and Hydrogen, also could be to Methane and other combustible steam, it is with low cost and suitable for different application.

Character : 

• Good sensitivity to Combustible gas in wide range.
• High sensitivity to LPG, Propane and Hydrogen.
• Long Life and Low Cost.
• Simple drive circuit.

Application :

• Domestic gas leakage detector.
• Industrial Combustible gas sensor.
• Portable gas sensor.

Configuration :

Technical data :

Basic test loop : 

The figure above is the basic test circuit of the sensor. The sensor need to be put 2 voltage, heater voltage ( VH ) and test voltage ( VC ). VH used to supply certified working temperature to the sensor, while VC used to detect voltage ( VRL ) on load resistance ( RL ) whom is in series with sensor. The sensor has light polarity, Vc nedd DC power. VC and VH could use same power circuit with precondition to assure performance of sensor with better performance, suitbale RL value is needed : 

Sensitivity Characteristics :

Graph shown above is the typical sensitivity characteristics of the MQ 2, ordinate means resistance ration of the sensor ( Rs / Ro ), abscissa is concentration of gases. Rs means resistance in different gases, Ro means resistance of sensor in 1000ppm Hydrogen. All test are under standard test condition.

Influence of Temperature/ Humidity :

Graph above shown the typical temperature and humidity characteristics. Ordinate means resistance ratio of the sensor ( Rs/Ro ), Rs means resistance of sensor in 1000ppm Butane under different temperature and humidity. Ro means resistance of the sensor in environment of 1000ppm Methane.

Structure and configuration :

Structure and configuration of MQ 2 gas sensor is shows at above, sensor composed by micro AL203 ceramic tube, Tin Dioxide ( Sn02 ) 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 2 have 6 pin, 4 of them are used to fetch signals, and other 2 are for providing heating current.

4) MQ 4 Semiconductor Sensor for Smoke and LPG.