Email: wisnuj@,cs.ui.ac.id and kusumo@,cs.ui.ac. id,. ABSTRACT. Locating the gas leak, chemical hazard source and smuggle-narcotic are difficult tasks done ...
IMPROVING THE ARTIFICIAL ODOR AND GAS SOURCE LOCALIZATION SYSTEM USING THE SEMICONDUCTOR GAS SENSOR BASED ON RF COMMUNICATION
@%nu Jatmiko and Benyamin Kusumoputro
Yuniarto
Faculty of Computer Science, University of Indonesia Depok Campus, Jakarta Indonesia, PO.Box 3443 Jakarta 10002 Phone:+62-2 1-7863419, Fax:+62-22-78634 15, Email: wisnuj@,cs.ui.ac.idand kusumo@,cs.ui.ac.id,
ABSTRACT Locating the gas leak, chemical hazard source and smuggle-narcotic are difficult tasks done by conventional system, because they usually exploit human expert or dog tracker to search and solve the problems. The electronic system that can perform such tracking automatically, constantly and accurately is expected to replace the duties. This paper will describe how the artificial system with such ability is realized. It can be used as a tool to conduct various applications, such as locating gas leaks and searching the chemical hazard.
Faculty of Mathematics and Science, Dep. of Physics Institut Teknologi Bandung, Ganesha 10
This sensor is lain on a miniature fan tunnel as the gas or odor goes through inside this tunnel. This research concluded that the system has a good ability to search the gas or odor location. However, the capability of system should be improved before applying in a larger outdoor area [7,8].
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1. INTRODUCTION
Detecting the source of leak, the chemical hazard and smuggled narcotics are difficult tasks done by conventional system, since they use human for detecting. Even though the human and the dogs have very good sense of smelling, their expertise are likely affected by physical condition and mood. It will influence the result of detecting, which is usually not constant and accurate. Since the conventional system consumes much time, large and expensive, the electronic nose is expected to replace dog trackers and the human detection system. The electronic system being developed is to mimic the dog tracker or human expert. In the animal behavior principle, the animal can search its prey, for example, the male search its female counterpart by tracking sexual pheromone or searching the food location. This paper will describe how the artificial system with such ability is realized, and can be used as a tool to perform various applications, such as locating gas leaks and searching the chemical hazard. They are several researches on mimicking the animal behavior by developing the electronic nose using the array sensor 11-53, and mobile robot that is controlled by computer. Our last research in gas or odor source localization system has been done using four semiconductor gas sensors that is placed in small mobile stage, however the movement of this mobile is still controlled manually [6]. Four semiconductor gas sensors to be used as sense nose detector is illustrated in Figure 1.
0-7803-7690-0/02/$17.00 02002 IEEE
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Figure 1. Module of Artificial gas or odor source localization system and semiconductor gas sensor Miniature fan tunnel
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Figure 2. Diagram Schematic of miniature fan tunnel experiment. This paper describes an improved system by replacing semiconductor gas sensor with TGS-822 semiconductor gas sensor, adding air inhaler and micro controller. The result shows that the new system have improvement in detecting the ethanol gas more stable than in our previous system.
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2. IMPROVEMENTTHE ARTIFICIAL GAS OR
2.1. Sensory System Improvement
ODOR LOCALIZATION SYSTEM
The last research on this system performed several weaknesses that must be improved. We will observe the limitation using four semiconductor gas sensors. If necessary we will reduce the amount of sensors to improve the capability of system. In this case we used TGS-822 semiconductor gas sensor. This system is also equipped with miniature fan as odor sucker; so in detection processing, it will make easier for the sensor to response the odor more rapidly and actively.
To enhance the probe of gas or odor tracing module, an improved artificial gas localization system has been made by replacing semiconductor gas sensor with TGS-822 semiconductor gas sensor, adding air inhaler and a micro controller. Its functions are to collect data from probe environment and to move the probe small mobile stage approaching the odor or gas source. The data processing module using the personal computer (PC) will process and store the data. Both modules communicate using the modem through FM transmission or generally said by modem radio [9]. This system will be trained in larger outdoor area. The explanation of the system improvement can be seen through Figure 3.
Module Communication Improvement
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Computer will control the movement of robot and give instruction to both stepping motors that will stimulate mobile stage of gas tracker to move and approach the odor location. The data communication between computer and mobile stage of gas tracker, using wireless RF communication, will be used for acquiring data and motor rotation. The aim of using the wireless radio is to give the tracker module can move more flexible in the larger outdoor area. 2.3.
Detection of odor source location training has been done in several methods, e.g. step by step searching method and zigzag searching method. To response rapidly from the sensory system, so the sensory system will rotate to 360 O using the step motor (If we use the less sensors). Before the gas or odor source localization system train in larger outdoor area, several experiments will be done in more wide miniature fan tunnel.
Figure 3. Diagram of artificial gadodor localization system Improvement
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Figure 5. The schematic of data processing module
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Receiver and transmitterFM
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3. THE PROCESS PROCEDURE OF ARTIFICIAL GAS SOURCE LOCALIZATION SYSTEM
tracker module in desirable direction (the result of data processing) by sending the signal through serial and then modem modulation will enter the FM transmission within the difference frequencies (instruction frequencies) [8,9]. The detail explanaition of processing procedure illustrates in Figure 6 and the prototype of system that has been developed can be seen in Figure 7.
The sensing element of TGS-822 gas sensors is a tin dioxide (Sn02) semiconductor that has low conductivity in clean air. In the presence of a detectable gas, the sensor's conductivity increases depending on the gas concentration in the air. A simple electrical circuit can convert the change in conductivity to an output signal which corresponds to the gas concentration. The TGS-822 has high sensitivity to the vapors of organic solvents as well as other volatile vapors. It also has sensitivity to a variety of combustible gases such as carbon monoxide, making it a good general purpose sensor. At the first step the TGS-822 sensor will be rotated 180" and divided in 28 points to gather the data. The point of gathering data will be read the output voltage of sensor and it will changed to the mathematic number between 0255 by Analog to Digital Converter. The data are collected and sent to data processing module after demodulation by modem through FM transmission and enter through serial device in computer. It can be seen in Figure 4 and Figure 5. Computer will save the 28 points of data. Data processing will compare the biggest value among alcohol concentrate, output voltage and data in byte. From the 28 points of data experiment divided in 5 rotations area gas tracker module. PC will instruct BS-1 to rotate the gases
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4. EXPERIMENTRESULT The first experiment of artificial gas or odor localization system is to find the odor source location. The system will scan the odor source that is located in front of gas tracker module in five directions toward clockwise; -90°(1eft side), -45'(left side), Oo(straight ahead)' +4S0 (right side) and +90°(right side). However, the system can only determine 5 directions, because the micro controller of the system is insufficient memory. The constraint that are used in this experiment: the diameter of alcohol container 7,115 & 0,001 cm, alcohol concentration 70% and close of the gas source equipped with the miniature fan 220Volt AC. Before we do the system treatment, it is necessary to know the successful level of odor tracker to identify the validate direction of odor source. The training of each source point in this experiment is taken 20 times continually [8, 91. The result of this experiment can be seen in Figure 8.
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Input data from all direction of sensors
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Determinethe highest intensity from the all direction of sensors
w Detemune the direction of odor source location, then move and rotate to the odor source
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Fimre 6 The Flowchart of gas or odor source localization system
Figure 7. Prototype of artificial gas or odor source localization
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REFERENCES [11. Benyamin Kusumoputm (PI), “Gas detection using
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the quartz resonator and neural network method System ”, Result of Research Presentation RUTIV,Serpong, Januari 1996 [2]. Benyamin Kusumoputm dan Muhammad Rivai, “Developmentoffrequency measure and experiment in Gas Detection using Quartz Resonator”, Science Publication PPI-KIM LIPI, 1996,376-386 [3]. B.Kusumoputro and H. Budiarto, ”Articial odor dkcrimination system using @zzy learning vector quantization neural network”, to appear on IASTED Proc. Artifi. Intelli. and Soft Comput., May 27-30, Cancun, Mexico, 1998. [4]. B.Kusumoputro and M. Rivai, “Discrimination of fragrance odor by arrayed quartz resonator and a neural network‘’, ICCIMA’98, Eds H.Selvaraj and B. Verma, World Scientific Pte.Ltd, Singapore, 1998,264-269 [5]. B. Kusumoputm and M. Rivai, “Artificialelectronic nose for diwriminating odor using a quartz resonator sensor array and a neural network”, Proc. Comput. Methods and Simult. in Engi., VII.A.4, 1997 [6]. H. Ishida, Y Kagawa, T. Nakamoto and T. Moriizumi, Odor-souce localization in the clean room by an autonomous mobile sensing system, Sensors and ’Actuators, B-33( 1996) 115-12 1 [7]. H. Ishida, K. Suetsugu, T. Nakamoto and T. Moriizumi, “Study of autonomous mobile sensing system for localization of odor source using gas sensors and anemometric sensors ”, Sensors and Actuators, A-45 (1994) 153-157 [8]. Sutrisno, “Developing of Odor identification and detection using the semiconductor sensor TGS-822 model”, Magister Thesis, Universitas Indonesia 1997 (under supervisor Dr. Benyamin Kusumoputro). 191. Yuniarto, “Sistem Otomatisasi Pelacakan Odor Alkohol Dengan Menggunakan Sensor TGS-822 dan Basic Stamp Camputw”,’hgas Akhir, Bandung Institute of Teknologi 2000 (under supervisor Dr. Benyamin Kusumoputro.
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Figure 8. The percentage of successful Level of the sensor to identify the validate direction in the distance 40 cm
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Figure 9. The step that is need by gas tracker module to search the odor source with the difference distance The second experiment is to test the number of step that is needed by artificial gas source localization system to trace and reach the odor source with the difference distance. 5. CONCLUSION AND SUGESTION
This experiment concluded that improvement the artificial gas or odor source localization system could search the gas or odor source on five directions in difference distance. This system has high successful level more than 70% to trace the odor in distance 40 cm. While, maximum distance that is required to scan the odor is 100 cm. To improve the capability of system is by enlarging the capacity of micro controller to read the plenty of data accurately from the several directions (more than 5 directions).
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