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Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

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A Presentation on Electronic-NOSE (E-NOSE) By- MAYANK SAHU, From - KNS Institute of Technology, Bangalore. An electronic nose is a device intended to detect odors or flavours. It is based on “Electronic sensing” or “e-sensing” technology . E-NOSE consists of certain mechanisms such as an array of electronic sensors for chemical detection and artificial neural network for pattern recognition.

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Page 1: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU
Page 2: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

CONTANTS INTRODUCTION WORKING OF E-NOSE COMPARISON OF E-NOSE WITH

BIOLOGICAL NOSE APPLICATIONS ADVANTAGES CHALLENGES INVOLVED FUTURE ASPECTS CONCLUSION REFERENCES

Page 3: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

INTRODUCTION An electronic nose is a device intended to detect

odors or flavours. It is based on“Electronic sensing”or“e-

sensing”technology . E-NOSE consists of certain mechanisms such as an

array of electronic sensors for chemical detection and artificial neural network for pattern recognition.

Page 4: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

WHAT IS E-SENSING?

“Electronic Sensing” refers to the capability of reproducing human senses using sensor arrays and pattern recognition systems.

It has undergone important development from a technical and commercial point of view.

Page 5: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

WORKING OF E-NOSE The electronic nose was developed in order to

mimic the human olfaction. It consists of arrays of sensors which are able to

generate electrical signals in response to either simple or complex volatile compounds present in the gaseous sample.

Essentially, e-nose consists of three major parts:

Sample Delivery System. Detection System. Computing system.

Page 6: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

WORKING OF E-NOSE

1) Enables generation of a sample which is to be analyze.

2) Then it is injected to detection system.

1. Sample Delivery System

2. Detection System.

1) Contains a group of sensors to sense the compound

2) Sensors react to the compound and the response is recorded by an electronic interface.

3) Transforms signal into digital value.

Page 7: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

WORKING OF E-NOSE

1) It combines the responses of all sensors to produce a result.

2) These results can be easily analyzed with a database of qualified samples.

3) New samples are identified by comparing those with the samples in database.

3. Computing system

Page 8: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

BASIC DESIGN

BLOCK DIAGRAM

Odour Delivery

Sensor Array Chamber

Signal Conditioning

Data Acquisition

Signal Processing

Pattern Recognition

SAMPLE SENSOR ARRAY

VAPOR SIGNALS RESULT

PATTERN RECOGNITION

Page 9: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

1) In a typical e-nose, an air sample is pulled by a vacuum pump through a tube into a small chamber housing the electronic sensor array.

2) A sample-handling unit exposes the sensors to the odorant, producing a response as the VOCs interact with the active material.

3) The sensor response is recorded and delivered to the Signal-processing unit.

4) Then a washing gas such as alcohol is applied to the array for a few seconds or a minute, so as to remove the odorant mixture from the active material.

Working in detail

Page 10: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

Based on the type of sensors employed, e-nose can be classified into the following categories:

1) Conductivity Sensors

2) Polymer Sensors

3) Piezoelectric Sensors

4) FET Gas Sensors

5) Optical Sensors

Working in detail

Page 11: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

CONDUCTIVITY SENSORS:-

These types of sensors exhibit a change in conductance when exposed to volatile organic compounds.

POLYMER SENSORS :-

Here the active material is a conducting polymer from such families as the Polypyrroles, thiophenes, indoles or furans. Changes in the conductivity of these materials occur as they are exposed to various types of chemicals, as certain reactions take place.

Working in detail

Page 12: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

All of the polymer films on a set of electrodes (sensors) start out at a measured resistance, their baseline resistance. If there has been no change in the composition of the air, the films stay at the baseline resistance and the percent change is zero.

Working in detail

e- e- e- e- e- e-

Page 13: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

Each polymer changes its size, and therefore its resistance, by a different amount, making a pattern of the change

Working in detail

e- e- e-e- e-e-

e-e-

e-e- e-

e-

If a different compound had caused the polymer to change, the pattern of the polymer films' change would have been different.

Page 14: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

PIEZOELECTRIC SENSORS:-

A piezoelectric sensor is a device that uses the piezoelectric effect to measure any physical change like pressure, strain etc. Here, the gas adsorption leads to change in mass of the sensor .

FET GAS SENSORS:-

Chemical FET(Field-effect transistor) is a type of a field-effect transistor acting as a chemical sensor. In this, the charge on the gate electrode is applied by a chemical process which may be used to detect atoms, molecules, and ions in liquids and gases .

Working in detail

Page 15: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

OPTICAL SENSORS:-

These utilize glass fibers with a chemically active material coating on their sides or ends.

A light source is used to interrogate the active

material which responds with the change in color to the presence of VOCs.

The active material contains chemically active

fluorescent dyes. As the VOCs interact with it, the color of the fluorescent dye changes, hence lead to detection.

Working in detail

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FEW SENSORS

Page 17: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

E-NOSE The Cyranose 320 is a

handheld “electronic nose” developed by Cyrano Sciences of Pasadena, California in 2000.

Applications researched using the Cyranose 320 includes the detection of COPD, and other medical conditions as well as industrial applications generally related to quality control or contamination detection.

Page 18: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

COMPARISON OF E-NOSE WITH BIOLOGICAL NOSE

BIO- NOSE E-NOSE1. It uses the lungs to bring the odor to

epithelium layer.

2. It has mucus, membrane and hair to act as filter.

3. The human nose contains the olfactory epithelium, which contains millions of sensing cells that interact with the odorous molecules in unique ways.

1. It employs a pump to smell the odor.

2. It has an inlet sampling system that provides filtration.

3. E-nose has a variety of sensors that interact differently with the samples provided.

Page 19: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

COMPARISON OF E-NOSE WITH BIOLOGICAL NOSE

BIO NOSE E-NOSE

4. The human receptors convert the chemical responses to electronic nerve impulses whose unique patterns are propagated by neurons through a complex network before reaching the higher brain for interpretation.

4. Similarly, the chemical sensors in the E-nose react with the sample and produce electrical signals. A computer reads the unique pattern of signals, and interprets them with some form of intelligent pattern classification algorithm.

Page 20: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU
Page 21: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

APPLICATIONS

In environmental monitoring:

• For identification of volatile organic compounds in air, water and soil samples.• For environmental protection.

In quality control laboratories:

• Conformity of raw material, intermediate and final products.

• Detection of contamination, spoilage and adulteration.• Monitoring of storage conditions.

Page 22: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

APPLICATIONS For medical diagnosis:-

• As the sense of smell is an important sense to the physician, an e-nose has applicability as a diagnostic tool. It can examine odors from the body and thus can identify possible problems.

In food industry:-

• Currently, this is the biggest market for e-nose. Its applications include quality assessment in food production and monitoring various food items based on their odor.

Page 23: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU
Page 24: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

ADVANTAGES OVER BIO NOSE

• The human sniffers are costly as compared to• e-nose. Also detection of hazardous gases by

them is not possible.

• E-nose has wide range of sensitivity.

• Results obtained by e-nose are fast and more accurate.

• It is well- suited for repetitive or boring tasks.

• It can also detect substances which are not detected by our human nose, like mercury.

Page 25: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

CHALLENGES INVOLVED

• E-nose can only identify a standard set of odors which is stored in its database.

• Though it is effective but still it can’t mimic the complex human olfactory system exactly.

• They also have shorter lifetime because of the sensors employed in them.

• Moreover, e-noses available in market are not economical.

Page 26: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

FUTURE ASPECTS OF E-NOSE In the field of health and security:

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

• It is used to detect bacterial contamination in the food products.

• It can be used to detect the cancers like brain and lung cancer.

• A more futuristic application of e-nose has been recently proposed for telesurgery.

Page 27: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

FUTURE ASPECTS OF E-NOSE In the field of crime prevention:-• The ability of the electronic nose to detect

odorless chemicals makes it ideal for use in the police force, such as to detect drug odors despite other airborne odors capable of confusing police dogs. However this is unlikely in the mean time as the cost of the electronic nose is too great and until its price drops significantly it is unlikely to happen.

• It may also be used as a bomb detection method in airports. Through careful placement of several or more electronic noses and effective computer systems you could triangulate the location of bombs to within a few meters of their location in less than a few seconds.

Page 28: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

CONCLUSION• An electronic nose is a system created to mimic the

functioning of human nose.

• Since the whole working is automatic, it can also be used by non specialists.

• Although it has several advantages, yet it is still far from the selectivity provided by a human nose.

• Basically, it is a tool provided to overcome the shortcomings of human nose thus giving us more fast and accurate results.

• Future developments in the use of advanced sensor arrays and the development of adaptive artificial neural networking techniques will lead to superior electronic noses.

Page 29: Seminar on Electronic-NOSE (E-NOSE) By- MAYANK SAHU

http://en.wikipedia.org/wiki/Electronic_nose

www.enose.info/environmental.html

http://enose.jpl.nasa.gov

http://science1.nasa.gov/2004/06oct_enose

H. V. Shurmur, “The fifth sense: on the scent of the electronic nose” IEEE Review, pp:- 59-98, March 1990

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