17-03-2011, 11:57 AM
presented by:
ANKIT GUPTA
enose.ppt (Size: 5.84 MB / Downloads: 277)
INTRODUCTION
• The expression “e sensing” refers to the capability of reproducing human senses using sensor arrays and pattern recognition system
• An electronic nose is a device used to detect odors and flavors
• Over the last decades “e sensing “ technologies undergone important developments
E-NOSE WORKING PRINCIPLE
Electronic nose mainly consist three major parts-
E-NOSE
A sample delivery system
A detection system
A computing system
SAMPLE DELIVERY SYSTEM
The sample delivery system enables the generation of the headspace (volatile compounds) of a sample, which is the fraction analyzed. The system then injects this headspace into the detection system of the electronic nose. The sample delivery system is essential to guarantee constant operating conditions.
DETECTION SYSTEM
• In detection system it consist of sensor set which is reactive part of instrument.
• When in contact with volatile components there is a change in properties of sensors
• Most e-noses uses sensor arrays that react to volatile components on the sensor surface causes a physical change of the sensors.
COMPUTING SYSTEM
• The computing system works to combine the responses of all sensors which represents the input for data treatment.
• This part of instrument perform global finger prints analysis and provides result and representation that can be easily interpreted
ARRAY BASED SENSORS
Sensitivity: measure of the change in output of a sensor for a change in input
Why do we use sensor array?
Each sensor responds to different chemicals in varying degrees
An array of sensors will give an overall response pattern that is unique for a given chemical .
SENSORS
• CALORIMETRIC
• CONDUCTING
• PIEZOELECTRIC
Calorimetric
• Calorimetric is the science of measuring the heat of chemical reactions or physical changes. It is performed with calorimeter.
• It is preferred for combustible test materials.
• Use temperature rise results in oxidation process which used for detection system
METAL OXIDE SENSORS
N-TYPE MOS SENSOR-
Ambient O2 chemisorb on the sensing film surface.
Reducing target gas (eg CO) react with O- and releases e-
Oxidizing agents (e.g. NO2) remove more e-
PIEZOELECTRIC CRYSTAL
• A piezoelectric sensor is a device that uses the piezoelectric effect to measure pressure, acceleration, strain or force by converting them to an electrical signal.
• Depending on peizomaterial cut it has three main modes-
• 1.Longitudnal mode.
• 2.Transverse mode.
• 3.Shear mode.
ANKIT GUPTA
enose.ppt (Size: 5.84 MB / Downloads: 277)
INTRODUCTION
• The expression “e sensing” refers to the capability of reproducing human senses using sensor arrays and pattern recognition system
• An electronic nose is a device used to detect odors and flavors
• Over the last decades “e sensing “ technologies undergone important developments
E-NOSE WORKING PRINCIPLE
Electronic nose mainly consist three major parts-
E-NOSE
A sample delivery system
A detection system
A computing system
SAMPLE DELIVERY SYSTEM
The sample delivery system enables the generation of the headspace (volatile compounds) of a sample, which is the fraction analyzed. The system then injects this headspace into the detection system of the electronic nose. The sample delivery system is essential to guarantee constant operating conditions.
DETECTION SYSTEM
• In detection system it consist of sensor set which is reactive part of instrument.
• When in contact with volatile components there is a change in properties of sensors
• Most e-noses uses sensor arrays that react to volatile components on the sensor surface causes a physical change of the sensors.
COMPUTING SYSTEM
• The computing system works to combine the responses of all sensors which represents the input for data treatment.
• This part of instrument perform global finger prints analysis and provides result and representation that can be easily interpreted
ARRAY BASED SENSORS
Sensitivity: measure of the change in output of a sensor for a change in input
Why do we use sensor array?
Each sensor responds to different chemicals in varying degrees
An array of sensors will give an overall response pattern that is unique for a given chemical .
SENSORS
• CALORIMETRIC
• CONDUCTING
• PIEZOELECTRIC
Calorimetric
• Calorimetric is the science of measuring the heat of chemical reactions or physical changes. It is performed with calorimeter.
• It is preferred for combustible test materials.
• Use temperature rise results in oxidation process which used for detection system
METAL OXIDE SENSORS
N-TYPE MOS SENSOR-
Ambient O2 chemisorb on the sensing film surface.
Reducing target gas (eg CO) react with O- and releases e-
Oxidizing agents (e.g. NO2) remove more e-
PIEZOELECTRIC CRYSTAL
• A piezoelectric sensor is a device that uses the piezoelectric effect to measure pressure, acceleration, strain or force by converting them to an electrical signal.
• Depending on peizomaterial cut it has three main modes-
• 1.Longitudnal mode.
• 2.Transverse mode.
• 3.Shear mode.