Smart Sensors 2

8/13/2019 Smart Sensors 2

1/9

SMART SENSORS

SMART SENSORS


2/9

ABSTRACT

Smart sensors are sensors with integrated electronics that can do one or more

following functio

ns:- Logic functions, two-way communication, make decisions. It consists of transduction

element, signal conditioning electronic and controller or processor that supports some

intelligence in a single package. This paper introduces concept of smart sensors

systematically. The progress in the integrated circuits become possible because of the

tremendous progress in semiconductor technology resulted in the low cost

microprocessor. By designing a low cost sensor, which is silicon based, the o erall cost

of the control system can be reduced. The usefulness of silicon technology as a smartsensor, physical phenomena of con ersion to electrical output using silicon sensors,

characteristics of smart sensors. The silicon sensor can produce output, as oltage,

current, resistance or capacitances, output format can be analog or digital. Suitable signal

conditioning circuits along with processor can easily designed using silicon technology.

The presence of controller or processor in smart sensor has lead to corrections for

different undesirable sensor characteristics which include input offset and span

ariations, non-linearity and cross sensiti ity. !s these are carried in software, no

additional hardware is re"uired and thus calibration becomes an electronic process.

#educed cost of bulk cables and connectors, cost impro ement and remote diagnostics

are the "ualities of smart sensors. In this paper specifically laser based smart displaced

sensor is e$plained, how smart sensors help anesthesiologist in !nesthesia super ision is

elaborated.


3/9

1.INTRODUCTION :

%e can ha e an integrated sensor, which has electronics and the transduction element

together on one silicon chip. This complete system can be called as system-on-chip .The

main aim of integrating the electronics and the sensor is to make an intelligent sensor, whichcan be called as smart sensor. Smart sensors then ha e the ability to make some decision.

&hysically a smart sensor consists of transduction element, signal conditioning electronic and

controller'processor that support some intelligence in a single package. Definition : -Smart

sensors are sensors with integrated electronics that can perform one or more function, a(

logic functions b( two-way communication c( make decisions.

) . USEFULNESS OF SILICON TECHNOLOGY IN SMART SENSOR:

There are ery con incing ad antages of using silicon technology in the construction ofsmart sensor. !ll integrated circuits employ silicon technology. ! smart sensor is made with

the same technology as integrated circuits. ! smart sensor utili*es the transduction properties

of one class of materials and electronic properties of silicon + a,!s(. ! transduction element

either includes thin metal films, *inc o$ide and polymeric films. Integrating electronic

circuits on the sensor chip makes it possible to ha e single chip solution. Integrated sensors

pro ide significant ad antages in terms of o erall si*e and the ability to use small signals

from the transduction element.

Signal on ersion ffects:

Sign ! Do" in E# "$!e% &Me %'(e)* E# "$!e% &+,-%i ! Effe t% in %i!i on*

#adiant Signals Light Intensity, polari*ation &hoto oltaic-effect, photoelectric effect

/echanical Signals 0orce, pressure, flow, acuum &ie*o-resisti ity

Thermal Signals Temp, Temperature radient Seebeck effect

hemical Signals oncentration, p1, to$icity Ion sensiti e field effect

/agnetic Signals 0ield intensity, flu$ density 1all effect

2ifferent silicon sensors can be obtained by employing abo e effects. The silicon

sensor can produce output as oltage, current, resistance or capacitance. 3utput format can

be analog or digital. Suitable signal conditioning circuits along with processor can easily be

designed using silicon technology. The presence of controller or processor in smart sensor

Transducer 4

Transducer )

Transducer n

3ffset correction andtemperature driftcompensation

! 53L3

/67

!4

!)

!n

S'14

S'1)

S'1n

!2

SS3#

Serialcommunication

/emory 2!


4/9

has lead to corrections for different undesirable sensor characteristics, which include input,

offset and span ariations, on linearity and cross sensiti ity. !s these are carried out in

software, no additional hardware is re"uired and thus calibration becomes an electronic

process.

/. Gene( ! A( ,ite t'(e of S" (t Sen%o( : It is similar to a data ac"uisition system,

the only difference being the presence of complete system on a single silicon chip. In

addition to this it has on-chip offset and temperature compensation.

Fig.1 Gene( ! A( ,ite t'(e of S" (t Sen%o(BLOC0 LE EL DESIGN CONSIDERATIONS FOR SMART SENSOR: 2 2esign choice

of smart sensor depends on the specific application for which the sensor

is re"uired and also related to specific industry.

3.I"$o(t n e n) A)o$tion of S" (t Sen%o( .: 0ollowing are "ualities of smartsensor:

a( #educed cost of bulk cables and connectors, b( #emote 2iagnostics

3.1 En, n e"ent of A$$!i tion: Smart sensor also enhances the following applications

a( Self calibration b( omputation c( ommunication d( /ulti-sensing.

Transducer 4

Transducer )

Transducer n

3ffset correction andtemperature driftcompensation

! 53L3

/67

!4

!)

!n

S'14

S'1)

S'1n

!2

SS3#

Serialcommunication

/emory 2!


5/9

3.4 S-%te" Re!i 5i!it- : System reliability is significantly impro ed due to the utili*ation of

smart sensors. 3ne is due to the reduction in system wiring and second is the ability of the

sensor to diagnose its own faults and their effect.

3./ I"$(o6e"ent in C, ( te(i%ti %: There is impro ement in following characteristics: 5on-linearity, ross-sensiti ity, 3ffset, &arameter drift and component alues.

3.3 S'"" (- of Diffe(ent S" (t Sen%o(%: Some of the smart sensors de eloped at different

research institutes are as follow:

O$ti ! Sen%o(: 2 3ptical sensor is one of the e$amples of smart sensor, which are used for

measuring e$posure in cameras, optical angle encoders and optical arrays. Similar e$amples

are load cells silicon based pressure sensors.

A e!e(o"ete(: !ccelerometer fabricated at the IB/ #esearch laboratory at San 8ose

alifornia, which consists of the sensing element and electronics on silicon. The

accelerometer itself is a metal-coated Si3) cantile er beam that is fabricated on silicon chip

Integ( te) M'!ti2Sen%o(: Integrated multi-sensor chip de eloped at the electronics research

Laboratory, 6ni ersity of alifornia. This chip contains /3S de ices for signal conditioning

with on chip sensor, a gas flow sensor, an infrared sensing array, a chemical reaction sensor,

a cantile er beam, accelerometer, surface acoustic wa e apor sensor, a tactile sensor array

and an infrared charge coupled de ice imager.

9. LASER BASED SMART DIS+LACEMENT SENSOR : The elements of

proposed light intensity

displacement smart sensor are an

optical con erter +2etectors( and

control, ac"uisition and

processing unit represented by a

Fig. 4 B!o 7 Di . S" (t Di%$! e"ent Sen%o(


6/9

Fig. /.Ang'! ( Di%t(i5'tion o f LD Be "

/icro controller. The stability of emitted laser beam is assured by a laser diode dri er that

controls the currents in ected in the laser, taking into account temperature. The emitted laser

beam has di ergence angle $;


7/9

9. Di%t(i5'te) S" (t Sen%o( S-%te" : ! distributed smart sensor system

consists of a network backbone, on which reside many nodes. 5odes may be loosely

classified as either sensor nodes or controller nodes. Sensor nodes are those, which tend to

send data to the network, and controller nodes are those, which tend to gather data from the

network.

0ig.5o.9 Smart Sensor System 0ig.5o.< &rototype Smart Sensor 5ode

! prototypical smart sensor node consists of three elements: a physical transducer, a

network interface, and a processor'memory core. The transducer senses the physical "uantity

being measured and con erts it into an electrical signal. Then the signal is fed to an !'2

con erter, and is now ready for use by the processor. The processor will perform some signal

processing on the data, and depending on how it is programmed, may send the resulting

information out to the network. 5etwork transactions are handled by the network interface


8/9

block. 5ote that these are only functional definitions and that / /S technology potentially

allows all three blocks to be implemented on a single die. ! prototypical controller node

consists of processor'memory, a network interface, and input'output de ices for

communicating with human users. It is used to collect information from the sensor nodes, to

program the sensor nodes, and to pro ide feedback to the user. &lacing all the sensors on a

common network bus enables Hplug and playH ease of installation. That is, no new wires ha e

to be routed to accommodate new nodes.

. S+ECIFIC A++LICATION OF SMART SENSOR IN MEDICAL

FIELD: THE ANAESTHESIA SU+ER ISION:

!ctually, the essential difficulty of !naesthesia super ision results of the fact that, each

characteristic signal +!de"uate entilation of lungs, ade"uate circulation, and intra cranial

pressure( is assessed separately. onse"uently, it is difficult for the anesthesiologist to

e aluate the patientFs conditions. /oreo er, he should be able to distinguish e"uipmentFs

dysfunction of a real ariation of the patient state. So propose a new architecture for

!naesthesia super ision, based on concept of smart sensor.

Aalidation data processing

&atient

!#2I3 !& !&53/! !5 /35

Aalidated data bare

#ough 2ata Base

laborated Information andnewser ices

!nesthesiologist

&atient

Sensor 5

entral Super ision 6nit

ommunication medium of field bus type

Sensor )Sensor 4


9/9

0ig.5oC entral 2ata &rocessing 6nit 0ig.5o. !rchitecture of !naesthesia Supe ision

T,e Cont(i5'tion of t,i% %-%te" (e % fo!!o8% :-4. The elaboration of a rate order from the

trend cur e of pressure measure and precedent rate.). The super ision of the difference

between the intracranial pressure and mean arterial pressure.

11 . CONCLUSION Smart sensors are becoming a considerable part of arious

fields such as industries, medical, defense. Silicon plays an important role in de elopment of

smart sensors. Still a lot of research is re"uired to get benefits of smart sensors.

Documents

Smart Sensors 2