Department of Electrical Engineering

Electronic Systems

Sensors and Actuators

Introduction to sensors

Sander Stuijk

(s.stuijk@tue.nl)

2

5ES00 = 5CI30 + 5CI31 3 ECTS awarded for each CI course passed

3 Embedded systems

an embedded system is a device used to

control, monitor or assist the operation of

equipment, machinery or plant.

“embedded" reflects the fact that the information

processing system is an integral part of the

device.

4 Embedded systems

embedded systems make up a large percentage of the product cost

embedded systems are the driving force behind the

only silent revolution the world has ever seen

5 Embedded systems

embedded systems are different from

personal computers

embedded systems are

reliable

consider many demands

(energy, code size, ...)

designed for a specific application

often real-time

often reactive

6 Embedded systems

an embedded system consists of

an actuator

a sensor

an embedded processor

and often a communication network

processor

sensor

actuator

communication

7

PRACTICAL NOTES

8 Prior knowledge

you should be familiar with the following subjects

signal processing

electronics

special lectures and labs are organized for students that lack this

background ...

9 Prior knowledge – signal processing

you should be familiar with ...

sinusoidal waves

complex numbers, phasors and phasor addition rule

spectral representation of signals, harmonic frequencies and

multiplication

Fourier transform

AD/DA conversion: sampling, quantization and under-sampling

FIR filter

power and noise

lectures on this topic are ...

mandatory for BTI, BTB, BTW, BID, BST, BW

part of `digital signal processing (5HH30)’

lecture on Thursday (optional), instruction on Friday

exam question during exam of 5CI30

10 Prior knowledge – signal processing

example question

11 Prior knowledge – electronics

you should be familiar with ...

passive components (R, L, C)

operational amplifiers

complex impedance of a circuit

circuits needed for AD/DA conversion

circuits needed for filtering

transistors

lectures on this topic are ...

mandatory for BTI, BTB, BTW, BID, BST, BW

part of `actuation techniques (5CI31)’

12 Prior knowledge – electronics

example question

Z4

+

-

Vin

Vout

i2

i3

V-

V+

i1Z1 Z2

Z3

Va

Figuur 4

5.1 In Figuur 4 is een schakeling met een opamp getekend. Veronderstel dat de

eigenschappen van de opamp ideaal zijn.

a. Wat is de relatie tussen V+ en V- ? (0.2/2.5)

b. Stel de Kirchhoff stroomwet op voor punt Va. (0.2/2.5)

c. Bereken de spanning Va als functie van Z1 ,Z2, Z3 en Vin met behulp van de Kirchhoff

stroom wet. (0.4/2.5)

d. Bereken i2. (0.2/2.5)

e. Beschrijf Vout als functie van Z1 ,Z2, Z3, Vin en Z4 (0.4/2.5)

13 Schedule (Quartile 1)

physics (BEI, BTN, BBT)

electronics (BTI, BTB, BTW, BID, BST, BW)

students join instructions of 5HH30 (digital signal processing)

14 Schedule (Quartile 2)

physics (BEI, BTN, BBT)

electronics (BTI, BTB, BTW, BID, BST, BW)

location to be announced later

15 Exam

written exam of 3 hours

includes question on signal processing (if applicable)

no notebooks allowed

exam scheduled in Q2 (January 23th) and Q3 (April 17th)

16 Course material

book

J. Fraden, Handbook of Modern Sensors: Physics, Designs, and

Applications, ISBN 978-0-387-00750-2

available online from Springer

additional material from OASE

Introducing Electronics

Signal processing: the basics

slides, instruction exercises, old exams

www.es.ele.tue.nl/education/SensorsActuators

video lectures from 2011-2012 (no instructions)

videocollege.tue.nl

17 Course material

exercises and short questions embedded in slides

marked in bold with question mark

solutions provided on slides

instructions

exercises available on the website

solutions provided on blackboard, not available online

exams

some previous exams available on the website

no answers or solutions provided (ask in case of doubt)

one exam will be practiced in week 14

18 A few words on 5CI31…

Studenten EE, N, BMT

week 1 Sept 4/6

week 2 Sept 11/13

week 3 Sept 18/20

week 4 Sept 25/27

week 5 Oct 2/4

week 6 Oct 9/11

week 7 Oct 16/18

week 8 Oct 23/25

Woe, uur 7-8 MF 07

X Instructions X Instructions Instructions X Instructions Instructions

Vri, uur 3-4 MF 07

Actuators Actuators Actuators Displays Displays Actuators Actuators Actuators

Vri, uur 7-8 PT 6.05

X Advanced Actuators

Advanced Actuators

Advanced Actuators

Advanced Actuators

Advanced Actuators

Advanced Actuators

Advanced Actuators

Andere studenten

week 1 Sept 4/6

week 2 Sept 11/13

week 3 Sept 18/20

week 4 Sept 25/27

week 5 Oct 2/4

week 6 Oct 9/11

week 7 Oct 16/18

week 8 Oct 23/25

Woe, uur 7-8 MF 07

X Instructions X Instructions Instructions X Instructions Instructions

Vri, uur 3-4 MF 07

Actuators Actuators Actuators Displays Displays Actuators Actuators Actuators

Vri, uur 7-8 PT 6.23

Intro to Electronics

Intro to Electronics

Intro to Electronics

Intro to Electronics

Intro to Electronics

Intro to Electronics

Intro to Electronics

Intro to Electronics

Actuators, Advanced Actuators, Instructions: Aleksandar Borisavljevic Displays: Gerard de Haan Intro to Electronics: Ruud Sprangers

19 Software for 5CI31

Download and install Maxwell SV software from

http://www.ele.tue.nl/downloads/5ES00/MaxwellSV.zip

20

INTRODUCTION TO SENSORS (Chapter 1)

21 Sensors are everywhere...

22 Example – Smartphone

5Mpixel camera LED flash speaker

buttons optical trackball capacitive touch screen microphone

proximity/light sensor processing

23 Sensors and actuators

sensors and actuators are common devices

a system of any complexity cannot be designed without them

why can a system not perform its tasks without sensors?

complexity

uncertainty

dynamic world

detection / correction of errors

24 Information-processing systems

information-processing system consist of

sensors

interface electronic circuits

processing elements

actuators

interface electronics

signal processing

25 Example – Temperature control

sense the temperature of a CPU

control the speed of the fan to keep the temperature constant

A/D and signal conditioner can be separated from the processor

circuitry may be integrated into a “smart sensor”

26 Example – Level control system

information-processing system

sensor (sight tube + optic nerve)

processing (brain)

actuator (hand + valve)

this sensor converts radiant energy to electrical energy

27 Animal senses

bats

ultrasound (mechanical)

shark

electrical field

snake

thermal radiation

rats

touch (mechanical)

fish

sound vibrations

(mechanical)

birds

magnetic field

28

Signal domain

Energy domain

Signals-carrying energy

Radiant

Mass Mechanical Molecular

Thermal

Gravitational

Atomic

Nuclear

Electrostatic /

Electromagnetic

Radiant

Chemical

Mechanical Magnetic

Thermal Electrical

29 Sensors, transducers and actuators

Radiant

Chemical

Mechanical Magnetic

Thermal Electrical

a transducer converts a stimulus from a signal domain to another

signal domain

a sensor receives a stimulus and responds with an electrical signal

complex sensor direct sensor

an actuator converts an electrical signal to another signal domain

30 Example - loudspeaker system

a transducer converts a stimulus from a signal domain to another

signal domain

a sensor receives a stimulus and responds with an electrical signal

an actuator converts an electrical signal to another signal domain

mechanical signal mechanical signal electrical signal

sensor actuator

31 Electrical signal domain

why do we prefer a transducer that produces a signal in the

electrical domain?

a signal in any domain can be converted to a signal in the electrical

domain

energy does not have to be drained from the processes being

measured, instead an amplifier can be used

many electrical signal conditioners exist

many options exist to process, display and store electrical

information

it is easy to communicate electrical signals

32 Example - telephone

mechanical signal mechanical signal electrical signal

sensor actuator

microphone converts sound to change of resistance

no transduction takes place (no change of energy)

power source must be added to affect transduction

a telephone works in a different way

33 Sensor classification - excitation

an active sensor requires external power to operate

a passive (self-generating) sensor generates its own electrical signal

sensor classification

1 passive

2 passive

3 passive

4 active

5 passive

passive active

34 Sensor classification – sensor placement

a contact sensor requires physical contact with the object

a non-contact requires no physical contact with the object

an internal sensor is used within the data acquisition system itself

sensor classification

1 passive non-contact

2 passive contact

3 passive contact

4 active contact

5 passive internal

35 Sensor classification – reference point

an absolute sensor reacts to a stimulus on an absolute scale

a relative sensor senses the stimulus relative to a fixed or variable

reference

sensor classification

1 passive non-contact

2 passive contact

3 passive contact

4 active contact

5 passive internal

36 Sensor classification – physical effect

transducers (sensors) employ physical effects to convert a stimulus

from a signal domain to another signal domain

in \ out radiation mechanical thermal electrical magnetic chemical

radiation photo

luminance

radiation

pressure

radiation

heating

photo-

conduction

photo-

magnetic

photo-chemical

mechanical photo-elastic

effect

conservation

moment

friction

heat

piezo-

electric

magneto-

strict.

pressure induced

explosion

thermal incandescen

ce

thermal

expansion

heat

conduction

Seebeck

effect

Curie-Weiss

law

endothermic

reaction

electrical inject

luminance

piezo-electric Peltier

effect

pn-junction

effect

Ampere’s

law

electrolysis

magnetic Faraday

effect

Magneto-

striction

Ettinghaus

en effect

Hall effect Magnetic

induction

chemical Chemo-

luminance

Explosive

reaction

Exotherma

l reaction

Volta effect Chemical reaction

37 Sensor classification – type / quantity measured

S

e

n

s

o

r

t

y

p

e

Quantity

Position, distance,

displacement

Flow rate /

Point velocity

Force Temperature

Resistive Magnetoresistor Thermistor Strain gage RTD

Potentiometer Thermistor

Capacitive Differential capacitor Capacitive strain

gage

Inductive and

electro-

magnetic

Eddy currents LVDT Load cell + LVDT

Hall effect Magnetostriction

LVDT

Magnetostriction

Self-

generating

Thermal

transport +

thermocouple

Piezoelectric

sensor

Pyroelectric sensor

Thermocouple

PN junction Photoelectric sensor Diode

Bipolar transistor

Digital Position encoder Quartz oscillator

Optic

Ultrasound Travel time Doppler effect

there are many other interesting quantities: acceleration, vibration,

humidity, level, pressure, velocity, ...