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    SEMINAR REPORT

    ON

    ELECTRONIC NOSE

    Submitted to S.R.M.S.C.E.T, Bareilly under the ordinance

    governing the course leading to the

    BACHELORS DEGREE

    IN

    ELECTRONICS AND COMMUNICATION ENGINEERING

    BY

    KM. NIRMAL

    EC-02(1001431906)

    SUBMITTED TO: MR. AMAN AGARWAL

    DEPARTMENT OF ELECTRONICS AND COMMUNICATIONENGG.

    Shri Ram Murti Smarak College of Engineering and

    Technology, Bareilly (U.P)

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    CERTIFICATE

    This is to certify that NIRMAL is a student of 6th semester B.TECH ECE, with

    registration no. 210105 in the batch 2009-2013 has taken active interest in

    preparing report on ELECTRONIC-NOSE.

    This is in potential fulfilment of requirement for the bachelor of technology

    degree in ELECTRONICS AND COMMUNICATION ENGINEERING, under

    SHRI RAM MURTI SMARAK COLLEGE OF ENGG. AND TECH. BAREILLY.

    This report is verified by:

    MR. B.R.DUTTA MR. AMAN AGARWAL

    Head Of Department Seminar Guide

    ECE, SRMSCET BAREILLY Dept. Of ECE

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    ACKNOWLEDGEMENT

    It is obvious that the development of a document of this scope needs the support of

    many people. The most important contribution to the development of a report such

    as this comes from the guide. I cannot express my gratitude in words to Mr. Aman

    Agarwalwho provided me helpful ideas and comments throughout the preparation.

    I would also like to acknowledge the contributions of my peers and other faculty

    members.

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    CONTENTS

    1. Certificate2. Acknowledgement3. Content4. Abstract5. Introduction6. Electronic nose system7. Working principle of E-Nose8. Physiological aspect of smell9. Types of sensors10. Comparison of E-Nose with biological nose11. E-NOSE advantage and disadvantage12. Digital scent communication13. Scent synthesisers14. Applications15. Future application16. Conclusion17. Reference

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    ABSTRACT

    Until now, online communication involved only two of our

    senses, sense of sight & sense of hearing. Soon it will involve the third, the sense

    of smell using an e-nose. Digital scent technology is the main application

    of e-nose. With digital scent technology, it is possible to sense, transmit&

    receive smell through internet. T h e r e i s c o m p l e t e s o f t w a r e a n d

    h a r d w a r e s o l u t i o n f o r i t . W h e n a p p l i e d t o c ommu ni ca ti on s,

    scent b ecomes a n ew infor mation chan nel . I t a l lows us to perceiveproducts and irate a previously unimagined emotionality and product

    credib i l i ty . Scents ex tend the myriad of mul t imedia poss ib i l i ty

    towards a new level. Scent communication will be one of the most important

    information tools of the future.

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    INTRODUCTION

    Until now online communication involved only two of our senses, sense ofhearing and sense of sight. Soon it will involve the third, the sense of smell. Anewtechnology is being developed to appeal to our sense of smell. Bringing alive ourexperience, technology now targets on the sense of smell. Using Electronic-nosewe can sense a smell and with a technologycal ledDigi talscent technology i t is possible to sense, t ransmit andreceive smel l through internet, like smelling a perfume online before buying

    them, sent scented-cards through scent enabled websites, and to experience theburning smell of rubber in your favourite TV games etc.If this technology gainsmass appeal no one can stop it from entering into virtual world. Just imagine youare able to smell things using a device connected to your computer. With Digitalscent technology this can be made a reality. There is complete software andhardware solution for scenting digital media and user.

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    ELECTRONIC NOSE SYSTEM

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    WORKING PRINCIPLE OF E-NOSE

    The electronic nose was developed in order to mimic human olfaction thatfunctions as a non-separative mechanism: i.e. an odor / flavor is perceived as aglobal fingerprint. Essentially the instrument consists of head space sampling,sensor array, and pattern recognition modules, to generate signal pattern that areused for characterizing odors.

    Electronic noses include three major parts:

    1.A sample delivery system

    2. A detection system

    3.A computing system

    BLOCK DIAGRAM OF E-NOSE

    A Sample delivery system:- The sample delivery system enables thegeneration of the headspace (volatile compounds) of a sample, which is thefraction analyzed. The system then injects this headspace into the detection systemof the electronic nose. The sample delivery system is essential to guaranteeconstant operating conditions.

    A Sample

    Delivery System

    A Detection

    System

    A Computing

    System

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    A Detection system:- The detection system, which consists of a sensor set, isthe reactive part of the instrument. When in contact with volatile compounds, thesensors react, which means they experience a change of electrical properties. Eachsensor is sensitive to all volatile molecules but each in their specific way. Mostelectronic noses usesensor arraysthat react to volatile compounds on contact: theadsorptionof volatile compounds on the sensor surface causes a physical change ofthe sensor. A specific response is recorded by the electronic interface transformingthe signal into a digital value. Recorded data are then computed based on statisticalmodels.

    The Computing ayatem:- The computing system works to combine theresponses of all of the sensors, which represents the input for the data treatment.This part of the instrument performs global fingerprint analysis an providesresults and representations that can be easily interpreted. Moreover, the electronicnose results can be correlated to those obtained from other techniques(sensorypanel,GC,GC/MS).

    http://en.wikipedia.org/wiki/Sensor_arrayhttp://en.wikipedia.org/wiki/Sensor_arrayhttp://en.wikipedia.org/wiki/Sensor_arrayhttp://en.wikipedia.org/wiki/Adsorptionhttp://en.wikipedia.org/wiki/Adsorptionhttp://en.wikipedia.org/w/index.php?title=Sensory_panel&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Sensory_panel&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Sensory_panel&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Sensory_panel&action=edit&redlink=1http://en.wikipedia.org/wiki/Gas_chromatographyhttp://en.wikipedia.org/wiki/Gas_chromatographyhttp://en.wikipedia.org/wiki/Gas_chromatographyhttp://en.wikipedia.org/wiki/GC/MShttp://en.wikipedia.org/wiki/GC/MShttp://en.wikipedia.org/wiki/GC/MShttp://en.wikipedia.org/wiki/GC/MShttp://en.wikipedia.org/wiki/Gas_chromatographyhttp://en.wikipedia.org/w/index.php?title=Sensory_panel&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Sensory_panel&action=edit&redlink=1http://en.wikipedia.org/wiki/Adsorptionhttp://en.wikipedia.org/wiki/Sensor_array
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    PHYSIOLOGICAL ASPECTS OF SMELL

    Before we describe the possibilities of olfactory displays, we shouldtake a glance at the physiological aspects of smell. How does the nose work andwhat is its function? Naturally we can breath, smell and additionally taste with ournose. First of all we are interested in the anatomy of the nose. Odor consists ofmany different molecules, for e.g. the aroma of coffee is made up of 20various molecules. Nonetheless our nose perceives only 15 odors which is enoughto identify the smell as coffee. At first the odor molecules reach the olfactorymucosa. The receptors for the mo le cu le s ar e pl ace d at th e ol fa ct or yhai rs . Whe n the mol ec ul es re ach the receptors, an electric impulse issent directly to the brain to the olfactory bulb. Then the information gets

    to the olfactory glomeruli, a part of the olfactory bulb. The glomeruli areable to associate the information to the intensity. The olfactory bulbconsequently processes the odor and can send the impulse to the olfactory brain.We notice that we have a direct connection between our sense of smelling and ourbrain. Those scent impulses reach the area of our brain that handlesemot ions and memories . That expla ins the l ink between smel l ingan d be in g reminded of something. We pe rc ep t sm el l ve ry in di vi du al ly .Every human perceive a difference between a pleasant and unpleasantodor. Humans are not capable to distinguish o dors in te rms of in tens i ty .

    Ro ug hl y we ca n on ly di st in gu is h b et we en th re e concentrations of someodor whereas we should actually be able to differentiate1 0 0 0 t y p e s o fo d o r s . A n o t h e r p r o b l e m f o r o l f a c t o r y d i s p l a y i st h e f a s t acclimatization of humans to scents. What makes it even moredifficult to construct olfactory display is that a setoff primary odor has not reallybeen found. There was an attempt to define seven such of primary odors buthad to be extended to 100 odors. For vision, three b as e co lo rs ar esuff ic ien t to d isp lay any color . Unfor tunate ly th is cannot beapplied to olfaction as our nose has thousands of receptors and apart from that theodors are not orthogonal. That means you will not necessarily get a new one b y

    m i x i n g t w o o d o r s . D u e t o t h e s e b i g p r o b l e m s t h e r e i s s t i l lr e s e a r c h i n examining our scent.

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    TYPES OF SENSORS

    E-nose is classified based on the type of sensors used.

    1. Conductivity Sensors2. Piezoelectric Sensors

    3. FET gas Sensors

    4. Optical Sensors

    5. Spectrometry based sensing methods

    1.Conductivity Sensors:- There are two types of conductivity sensor(i)metal oxide

    (ii) Polymer

    Both of which exhibit a change in resistance when exposed to volatile organic

    compounds.

    (i) Metal Oxide TypeWorking principle:- These sensors are made of a ceramic former heated

    by a heating wire and coated by a semiconducting film. These

    semiconductor sensors can sense gases by monitoring changes in the

    conductance during the interaction of a chemically sensitive material with

    molecules that need to be detected in the gas phase.

    They are used to detect toxic and flammable gases in domestic and

    environmental applications and form food aromas.

    (ii) Polymer Sensors

    Here the active material is a conducting polymer from such families as the polyp

    roles, thiophenes, insoles or furans. Changes in the conductivity of these

    materials occur as they are exposed to various types of chemicals, which bond

    with the polymer backbone. A given compound affinity for a polymer and itseffect on the polymer conductivity are strongly influenced by the counter ions

    and functional group attached to the polymer backbone. Here the response time

    is inversely proportional to the polymer thickness, which is usually in the range of

    10 to 20m.

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    2.Piezoelectric Sensors :-These are of two types of sensors

    (i) QCM (Quartz crystal Microbalance)(ii) SAW (Surface Acoustic Wave devices)

    Here they are configured as mass change sensing devices.

    (i) QCM (Quartz crystal Microbalance) Type:-It consists of resonating disc with metal electrodes on each side

    connected to read wire. The device resonates at a characteristic

    frequency (10 to 30 MHz), when excited with an oscillating signal.

    During manufacturing, a polymer coating is applied to the disc to serve

    as the active sensing material. In operation, a gas sample is adsorbed at

    the surface of the polymer, increasing the mass of the disk polymer

    device and thereby reducing the resonance frequency. The reduction is

    inversely proportional to the odorant mass adsorbed by the polymer

    when the sensor is exposed to a reference gas. The resonance frequency

    returns to the baseline value.

    (ii) SAW (Surface Acoustic Wave devices)Type:-Here a surface wave travels over the surface of the device. So sensors

    operate at much higher frequency and so can generate a large change infrequency. A typical SAW device operates in hundreds of Megahertz,while 10 MHz is more typical for a QCM. But SAW devices can measure

    changes in mass to the same order of magnitude as QCMs.

    3. FET gas Sensors:-

    The FET is a " metal "/ insulator / semiconductor structure in which the

    gate (the " metal ") can be any conducting layer or medium. The FET is a

    semiconducting device which acts as an amplifier (like a transistor). Thereare different FET configurations:

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    4. Optical Fibre Sensors:-

    These utilise glass fibres with a thin chemically active material coating on

    their sides or ends. A light source at a single frequency is used to

    interrogate the active materials, which responds with the change in colourto the presence of VOCs. The active material contains chemically active

    fluorescent dyes immobilized in an organic polymer matrix. As VOCs

    interact with it, the polarity of the fluorescent emission spectrum.

    5. Spectrometry Based Sensors:-

    Here a vapour trap is used to concentrate the VOCs and then it being

    injected into a spectrometer that generates a spectral responsecharacteristic of the vapour. Then the efficient signal processing technique

    can be used for finding out the odorant. Here the disadvantage is that is

    the use of highly complex electronic measuring device.

    Potentiometric Chemical Sensors Potentiometric Chemical Sensors are

    based on the measurement of a potential under no current flow. The

    measured potential may then be used to determine the analytical

    concentration of some components of the analytic solution. For useful

    definitions please go to Electrochemical terms and concepts. There existdifferent types of potentiometric chemical sensors. A classification shows

    the binding between them. This web-page will only develop the ion

    selective sensors (ISE) and the biosensors.

    Ion selective sensors (ISE)

    An ISE produces a potential which is proportional to the concentration of

    an analyse. Making measurements with an ISE is therefore a form of

    potentiometry. The most common ISE is the pH electrode, which contains

    a thin glass membrane that responds to the H+ concentration in a

    solution. Ion selective sensors are susceptible to several interferences.

    Samples and standards are therefore diluted 1:1 with total ionic strength

    adjuster and buffer (TISAB). The instrumentation of an ISE consists of the

    ion-selective membrane, an internal reference electrode, an external

    reference electrode, and a voltmeter. Different sorts of ion selective

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    membranes exist : the glass, the chalcogenide and the crystal membrane.

    Research currently focuses on chalcogenide membranes.

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    COMPARISION OF ELECTRONIC NOSE WITH

    BIOLOGICAL NOSE

    Each and every part of the electronic nose is similar to human nose. The function

    of inhaling is done by the pump which leads the gas to the sensors. The gas inhaled

    by the pump is filtered which in the human is the mucus membrane. Next comes

    the sensing of the filtered gas, which will be done by the sensors i.e., olfactory

    epithelium in human nose. Now in electronic nose the chemical retain occurs

    which in human body is enzyme reaction. After this the cell membrane gets

    depolarised which is similar to the electric signals in the electronic nose. This gets

    transferred as nerve impulse through neurons i.e., neural network and electronic

    circuitries.

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    APPLICATIONS OF ELECTRONIC NOSE

    The electronic nose has been used in a variety of applications and couldhelp solve problems in many fields. The electronic nose can be applied byfood manufacturers to such tasks such as freshness testing, quality screening ofincoming raw material, and monitor for accidental or intentional contamination. Inthe medical field, e nose has a variety of application such asrapiddiagnosis of acute infection through breath analysis and screeningof bacterial cultures for early detection of pathogens-nose can serve in safetyand security applications such as hazard alarm for toxic and biological agents,screening airline passengers for explosives and drugs. Its military applications

    include land- mine detect ion, biological and chemical agent detection etc.

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    E-NOSE: ADVANTAGES AND DISADVANTAGES

    ADVANTAGES

    It can be used without fall over hours, days, weeks and even months and can evencircumvent problems associated with the use of human panels such as individualvariability, adoption, fatigue mental state and exposure to hazardousmaterial. The e-nose is a compact device and so it is portable andreliability is very high. It can identify simple molecules which cannot beaccomplished by human nose. It can identify a smell objectively.

    DISADVANTAGES

    There are a few disadvantages tothe e-nose technology which includes the price.The cost of e-nose ranges from $5000 to $100,000. Another disadvantage has beenthe delay between successive tests, the time delay ranging between 2to 10minutes during which time, the sensor is to be washed by a reactivating

    agent, which is applied to the array so as to remove the odorant mixture from thesurface and bulk of the sensors active material.

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    DIGITAL SCENT COMMUNICATION

    The e-nose detects the smell molecules and it is indexed based on twoparameters. The scent is indexed according to its chemical make up and its place inthe scent spectrum. The chemical make up can be detected by theelectronicnose which otherwise act as the receiver. Like the color spectrum, thereis also scent spectrum and any smell will be the indexed smell of primarysmells in the scent spectrum. The indexed scent is digitized into a small file byolfactory signal processing. This file is sent as an attachment to the recipientscomputer. At the receiving end, there wi ll be a per sonal scent synthesizerand air cannon. The personal scent synthesizer reproduces the smell andthe air cannon direct the smell to users nose. The data about the smell isgiven by the digitally encoded file which is transmitted. The smell emitted willbe in the form of vapors.

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    SCENT SYNTHESIZERS

    Scent synthesizers are devices which are used to generate the smell inaccordance with the digitized file that is transmitted through the web. The scents y n t h e s i z e r s a r e i n t e r f a c e d w i t h o u r P C t h r o u g h a U S Bp o r t . I t c a n b e programmed or installed and it generates a small quantity

    of smell vapours into the surrounding that is enough to feel the smell. Allscent synthesizers will have are movable cartridge which is used to mixdifferent primary odors in different scent synthesizers. Digi scent is thecomp any whic h id enti fie d th e mo st numb er o f primary scents about128 primaries and the y co uld cr eat e up to 100 0 sm el ls using these

    primaries.

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    APPLICATIONS OF ELECTRONIC NOSE

    The electronic nose has been used in a variety of applications and couldhelp solve problems in many fields. The electronic nose can be applied byfood manufacturers to such tasks such as freshness testing, quality screening ofincoming raw material, and monitor for accidental or intentional contamination. Inthe medical field, e nose has a variety of application such as rapiddiagnosis of acute infection through breath analysis and screening ofbacterial cultures for early detection of pathogens-nose can serve in safetyand security applications such as hazard alarm for toxic and biological agents,screening airline passengers for explosives and drugs. Its military applications

    include land- mine detect ion, biological and chemical agent detection etc.

    Electronic nose instruments are used by research and development laboratories,quality control laboratories and process & production departments for variouspurposes:

    In quality control laboratories for at line quality control such as

    Conformity of raw materials, intermediate and final products Batch to batch consistency Detection of contamination, spoilage, adulteration Origin or vendor selection Monitoring of storage conditions.In process and production departments

    Managing raw material variability Comparison with a reference product Measurement and comparison of the effects of manufacturing process on

    products Following-up cleaning in place process efficiency Scale-up monitoring Cleaning in place monitoring.

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    In environmental monitoring

    For identification of volatile organic compounds in air, water and soil samples.(eg. Aqueous sensor network)

    For environmental protection.

    AQUEOUS SENSOR NETWORK

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    FUTURE APPLICATIONS

    Possible and future applications in the fields of health and security:-

    The detection of dangerous and harmful bacteria, such as software that has beenspecifically developed to recognise the smell of the MRSA (Methicillin-resistant Staphylococcus Aurous).[11]It is also able to recognisemethicillinsusceptible S. aurous (MSSA) among many other substances. It hasbeen theorised that if carefully placed in hospital ventilation systems, it coulddetect and therefore prevent contamination of other patients or equipment bymany highly contagious pathogens.

    The detection of lung cancer by detecting the VOC's (volatile organiccompounds) that indicate lung cancer.

    The quality control of food products as it could be conveniently placed in foodpackaging to clearly indicate when food has started to rot.

    Nasal implants could warn of the presence of natural gas, for those who hadanosmiaor a weak sense of smell.

    Possible and future applications in the field of crime prevention and

    security:- The ability of the electronic nose to detect odorless chemicals makes it ideal for

    use in the police force, such as the ability to detect drug odors despite otherairborne odors capable of confusing police dogs. However this is unlikely in themean time as the cost of the electronic nose is too great and until its price dropssignificantly it is unlikely to happen.

    It may also be used as a bomb detection method in airports. Through carefulplacement of several or more electronic noses and effective computer systemsyou could triangulate the location of bombs to within a few metres of their

    location in less than a few seconds.

    http://en.wikipedia.org/wiki/Electronic_nose#cite_note-10http://en.wikipedia.org/wiki/Electronic_nose#cite_note-10http://en.wikipedia.org/wiki/Electronic_nose#cite_note-10http://en.wikipedia.org/wiki/Volatile_organic_compoundhttp://en.wikipedia.org/wiki/Volatile_organic_compoundhttp://en.wikipedia.org/wiki/Volatile_organic_compoundhttp://en.wikipedia.org/wiki/Volatile_organic_compoundhttp://en.wikipedia.org/wiki/Anosmiahttp://en.wikipedia.org/wiki/Anosmiahttp://en.wikipedia.org/wiki/Anosmiahttp://en.wikipedia.org/wiki/Volatile_organic_compoundhttp://en.wikipedia.org/wiki/Volatile_organic_compoundhttp://en.wikipedia.org/wiki/Electronic_nose#cite_note-10
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    CONCLUSION

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