21-02-2010, 07:50 AM
electronic nose.ppt (Size: 2.61 MB / Downloads: 695)
INTRODUCTION
Electronic Nose is a device intended to detect odors or flavors.
The name e-nose comes from the expression e-sensing
ELECTRONIC NOSE
It is a modular system comprising a set of sensors which detect odours & transduce the chemical quantity into electrical signals, followed by appropriate signal conditioning and processing to classify known odours.
CONSTRUCTION
Mainly contain 3 major parts.
Sample delivery system
Detection system
Computing system
Sample delivery system
The sample delivery system enables the generation of the headspace of a sample, which is the fraction analyzed.
Detection system
The detection system, which consists of a sensor set, is known as the reactive part of the instrument.
Computing System
The computing system works to combine the responses of all of the sensors, which represents the input for the data treatment
COMPONENTS
¢ Comprise of set of active materials, chemical sensors, and signal conditioning & processing.
¢ Two main components:-
(a) sensing system
(b) Pattern recognition system
Working of chemical sensors
E nose uses a collection of 16 polymer films.
They are specially designed to conduct electricity.
Stray molecules are absorbed into films, they start expand due to conduction of electricity.
Each film react in a different way.
Variation of 16 films produce a distinctive and identifiable pattern.
Classification of sensors
>> Calorimetric
>> Conducting
>> Piezoelectric
Why is an Electronic Nose Better
Trained human Ëœsniffersâ„¢ are expensive
Individuals vary
Hazardous Chemicals
Can be done in real time for long periods
Advantage & Disadvantages
Advantages
Compact device
High portability
High reliability
High versatility
Disadvantages
High cost
Time delay between successive tests
Insensitivity to some species
According to application, e-nose used is changed
Future of the Electronic Nose
Research is being done on IC E-Noses
Miniaturizing Current Technology
Combination of several sensors
Manufacture of olfactory nerves
Less expensive more sensitive E-nose
Applications
Food industry
Medicine
Environmental monitoring
Military
Space stations
Multimedia
Conclusion
Humans are not well suited for repetitive or boring tasks that are better left to machines. Researches are still going on to make electronic nose much more compact than the present one and to make electronic nose I.C.s. In future we might be able to manufacture olfactory nerves.