Electronics nose - Nano Mahidol - Mahidol University

Electronics nose
Paisan Doungjak
Center of Complex Systems
School of Science, Walailak University
&
Center of Nanoscience and Nanotechnology
Faculty of Science, Mahidol University
Olfactory mechanisms

What is the electronic nose
Human mimic nose
Olfactory
epitheium
Proceedings of 2004 IEEE/RSJ international conference
ELECTRONIC NOSE
Conventional Olfactory laboratory
relies on human nose
But human nose get tired with more
samples….

ELECTRONIC NOSE
How electronic nose works:
Scheme of the human olfactory system.
Schematics of an electronic nose.
Electronic nose system :
ELECTRONIC NOSE
• Types of transducer sensor
- Quartz crystal Micro Balances (QMB)
- Surface Acoustic Wave Sensors (SAW)
- Metal Oxide Semiconductor Sensors
(MOS)**
- Metal Oxide Field Effect Transistors
(MOSFET)
- Conducting Organic Polymers (COP)

Optical sensor
Gravimetric Odor Sensors
Quartz crystal
microbalance, QCM
Surface acoustic
wave, SAW
Principal of QCM click!
booming cellular telephones
market
Base on piezoelectric substrate;quart,LiNbO 3 and ZnO

Chemoresistive sensors
Metal Oxide Semiconductors (MOS)
SnO 2
O
O
grains
2
2
O -
O - O -
2 O - 2 O - 2
O - 2
2 e - e - e
2 e e - e-
O - 2 O - e - ē -
2
O ē - 2 e - e -
e -
Space charge
region
O - 2
eē- O - 2
O - 2
O 2
e -
e -
e - O - 2
O - 2
O 2
+ e - O - 2
½O 2
+ e - O -
½O 2
+ 2e - O 2-
φ b
chemical equaltion :
1
−
e+ O2
⎯⎯→ O()
s
2
−
Rg ( ) + Os ( ) ⎯⎯→ ROg ( ) + e
O 2
CO O 2
CO
eē- e - e -
O - e -
e - e - 2
e - e
e e - e-
e - e-e- O e - e - e - e - e - e - e -
2
e - e -
O 2
O - 2 + CO CO 2 + e-
CO
O - + CO CO 2
+ e -
O 2- + CO CO 2
+ 2e -
φ b
Pattern Classify
Data analysis : Pattern Classification
• Statistical method
- Principal component analysis (PCA)
- Partial least-square (PLS)
- Principal component regression (PCR)
- Cluster analysis (CA) and etc.
• Biological non-parametric
methodologies artificial neural
network, ANNS)
- Multi-layer perception (MLP)
- Self-organizing map (SOM)
- Neural fuzzy system (NFS) and etc.

ELECTRONIC NOSE
Model base
Qualitative
Quantitative
Model free
Classification scheme of the multivariate
pattern analysis techniques in ENs
ELECTRONIC NOSE
PRINCIPAL COMPONENT ANALYSIS
Aim: lower dimensional representation
and visualization of the data in terms
of scores on (uncorrelated) principal
component > score plot
Measurement on p (correlated)
variances on n objects/ individuals/
experimental units
Choice to be made:
-covariance or correlation matrix (raw
or standardized data)
-the number of PC’s to be used

ELECTRONIC NOSE
Data acquisitions:
Data transfer can be used
-Serial port
-Parallel port
-Infrared transfer (iR)
-Bluetooth
-Wi-Fi
And to be collected by PC
Experimental setup
ELECTRONIC NOSE
– MATLAB TM TGS2602 VOCs and odorous gases
To electronics
• Four commercial MOS sensors (Now)
– Figaro : AF63, TGS822, TGS2600, TGS2602
sensor
• Static chamber + headspace analysis
– Concentration of coffee = 0.12g/litre
– 10 ml analytic odor in 125ml flask
analyte
– Sensor inserted through a tight aperture on the cap
– This setup eliminates cooling effects by effluent flow
• Analytic database
– Operation time used in 30 min.
Model Description (by manufactory)
• Interface requirements
AF 63 alcohol and gas leak
– LabVIEW TM
TGS 822 organic solvent vapors
– RS-232 port
TGS2600 Low concentrations of air
• Analysis programming
contaminates

ELECTRONIC NOSE
- the transducer to be used in EN
Odor samples:
ELECTRONIC NOSE
#
1
2
3
4
5
6
7
8
Type
Moccona-select
Moccona-royal gold
Nescafe-Redcup
Nescafe-Gold
Khao shong-brown
Khao shong-red
OEM-Big C
Superclass

ELECTRONIC NOSE
Results : the experiment data of Thai-coffees were collected
ELECTRONIC NOSE
Feature extraction – have many methods
- Maximum value was used to statistical recognition.
- signal preconditioning : wavelet transform (to be next time)
Maximum value

ELECTRONIC NOSE
Model base
Qualitative
Quantitative
Model free
Classification scheme of the multivariate
pattern analysis techniques in ENs
ELECTRONIC NOSE
Results : The principal component
analysis of Thai-coffees brand in
10, 25 and 40 degree Celsius
10 degree Celsius
25 degree Celsius
40 degree Celsius

ELECTRONIC NOSE
For application works
-To use analyses of freshness of product
e.g. Beverage, food product
-Environment monitoring :
e.g Aqueous sensor Network
-Movable robot,
Bomb detector,
rescue robot ,etc…