WHAT ARE EMBEDDED SYSTEMS?

We read in newspapers that a doctor had successfully transplanted a cardiac

pacemaker in his patient’s chest by sitting around 200kilometres away. Also we know about

driverless cars that could take us to the destiny by using its inbuilt navigation systems.

Embedded microprocessors or micro controllers are the brain behind these.

An embedded system is any device controlled by instructions stored on a chip. These

devices are usually controlled by a micro processor that executes the instructions stored on a

read only memory(ROM) chip.

The software for the embedded system is called firmware. The firmware will be written

in assembly language for time or resource critical operations or using higher level languages

like C or embedded C. The software will be simulated using micro code simulators for the

target processor. Since they are supposed to perform only specific tasks, these programs are

stored in read only memories(ROMs).Moreover they may need no or minimal inputs from the

user, hence the user interface like monitor, mouse and large keyboard etc,may be absent.

Embedded systems are computer systems that monitor, respond to, or control an

external environment. This environment is connected to the computer system through sensors,

actuators, and other input-output interfaces. It may consist of physical or biological objects of

any form and structure. Often humans are part of the connected external world, but a wide

range of other natural and artificial objects, as well as animals are also possible.

Embedded systems are also known as real time systems since they respond to an input

or event and produce the result within a guaranteed time period. This time period can be few

microseconds to days or months. The computer system must meet various timing and other

constraints that are imposed on it by the real-time behavior of the external world to which it is

interfaced. Hence comes the name real time. Another Name for many of these systems is

reactive systems, because their primary purpose is to respond to or react to signals from their

environment. A real time computer system may be a component of a larger system in which it

is embedded; reasonably such a computer component is called an embedded system.

Embedded systems control engine management systems in automobiles, monitor home

heating systems and regulate the quiet operation and the even distribution of laundry in

washing machines. They are the heart of toys like Furby and Tamagotchi, of golf balls that

cannot get lost and of gas pumps at gasoline stations that advertise nearby restaurants on video.

Above all, state-of-the art communications equipment like WAP mobile telephones, MP3

players, set-top boxes and Net devices would not be possible without these powerful miniature

brains.

Applications and examples of real time systems are ubiquitous and proliferating,

appearing as part of our commercial, government, military, medical, educational, and cultural

infrastructures. Included are:

Vehicle systems for automobiles, subways, aircraft, railways and ships.

Traffic control for highways, airspace, railway tracks and shipping lanes.

Process control for power plants, chemical plants and consumer products such as soft

drinks and beer.

Medical systems for radiation therapy, patient monitoring and defibrillation

Military uses such as firing weapons, tracking and command and control.

Manufacturing systems with robots.

Telephone, radio and satellite communications.

Computer games.

Multi media systems that provide text, graphic, audio and video interfaces.

House holds systems for monitoring and controlling appliances.

Building managers that controls such entities as heat, light, Doors and elevators.

IN THE DRIVING SEAT

There are several tasks in which real time OSs beat their desktop counterparts hands-

down. A common application of embedded systems in the real world is in automobiles because

these systems are cheap, efficient and problem free. Almost every car that rolls off the

production line these days makes use of embedded technology in one form or the other.RTOSs

are performed in this area due to their fast response times and minimal system requirements.

Most of the embedded systems in automobiles are rugged in nature, as most of these

systems are made up of a single chip. Other factors aiding their use are the low costs involved,

ease of development, and the fact that embedded devices can be networked to act as sub

modules in a large system. No driver clashes or ‘system busy’ condition happen in these

systems. Their compact profiles enable them to fit easily under the cramped hood of a car.

Embedded systems can be used to implement features ranging from adjustment of the

suspension to suit road conditions and the octane content in the fuel to anti lock braking

systems (ABS) and security systems. Speaking of the things nearer home the ‘computer chip’

that control fuel injections in a Hyundai Santro or the one that controls the activation of air

bag in a Fiat in a weekend in nothing but an embedded system. Right from brakes to

automatic traction control to air bags and fuel/air mixture controls, there may be upto 30-50

embedded systems within a present-day car. And this is just a beginning.

THE DOCTOR WILL SEE YOU NOW

Imagine a time when body transplants like cardiac pacemakers will be able to monitor

and manage themselves remotely. These systems will be so compact that the patient wouldn’t

even be aware that they are embedded in his body. Another point in favor of RTOSs is their

stability, instantaneous

response and efficiency. No OS crashes or delay in responding, as in the case with most

desktop OSes. After all, which patient can rest easy with the thought of his life literally

hanging by a thread due to the time taken by the OS to load!

Embedded technology advances are pointing towards the use of pace makers that can

be transplanted in or near the heart itself. The pacemaker will be able to monitor parameters

like blood pressure, blood flow, pulse rate, temperature, etc, using micro sensors planted in

various parts of the body. This capability will enable the pace maker to automatically vary its

operation to suit the changing body conditions. It will also transmit data using wireless

transmission, thus enabling a doctor to constantly monitor its operation. In most cases, wireless

transmitter implanted near the surface of the skin. In case any abnormality is detected the

doctor will be able to take remedial actions even from a remote location.

WIRED WEARABLES

A mobile phone in the form of a ring or an ear ring? What about cool sunglasses with

streaming video displays built into them? All these can soon be a reality. Embedded systems

have a small foot print and consume very little power which makes them ideal for wearable

computing applications.The minimal system requirements of these devices ensure that the

hardware is almost microscopic.

IBM is already working on the prototype of a mobile phone that can be worn as

jewellery.The components of the phone will be distributed among different pieces of jewellery

ear ring, necklace, ring and bracelet.

The phone is likely to have blue tooth capability built into it. The ear rings will have

embedded speakers and will act as the receiver. The necklace will have embedded micro

phones that will act as a mouth piece user can talk into. IBM called the ring part of the phone

the decoder ring. Light emitting diodes (LEDs) will flash to indicate an incoming call. The ring

will also have features that will enable it to be programmed to flash different colors for a

particular user or to indicate the importance of a call. A video graphics array (VGA) will be

built into the bracelet, which will display the name and phone number of the caller. The

bracelet will also integrate the keypad and the dialing functions in it. IBM plans to incorporate

voice recognition technology for dialing a number. The phone may also have features to

indicate new email.

DON’T KEEP YOUR EYES ON THE ROAD

Embedded systems can also make driverless vehicle control a reality. Major

automobile manufacturers are already engaged in work on these concepts. One such

technology is Adaptive Cruise Control (ACC).

ACC allows cars to keep safe distances from other vehicles on busy highways. The

driver can set the speed of his car and the distance between his car and others. When traffic

slows down, ACC alters vehicle speed using moderate braking. This ensures that a constant

distance is maintained between cars. As soon as traffic becomes less, ACC moves up to the

desired cruise speed that has been set by the driver. The driver can over ride the system any

time he wants to be breaking.

Each car with ACC has a micro wave radar unit or laser transceiver fixed in front of it

to determine the distance and relative speed of any vehicle in the path. The ACC computer

(What else but an embedded system or a grouped system of embedded system) constantly

controls the throttle and brakes of the car. This helps to make sure that the set cruise speed or

adapted speed of traffic at that time is not exceeded.

THE WORKING PRINCIPLE OF ADAPTIVE CRUISE CONTROL

As already mentioned each car with ACC have a micro wave radar unit fixed in front

of it to determine the distance and relative speed of any vehicle in it’s path. The principle

behind the working of this type of radar is- the Doppler Effect.

Doppler Effect:

Doppler Effect is the change in frequency of the waves when there is a relative motion

between the transmitting and receiving units. The two figures below clearly show the Doppler

Effect.

1. Higher Pitch Sound

In this case the vehicle is speeding towards the stationary listener. The distance

between the listener and the car is decreasing. Then the listener will hear a higher pitch sound

from the car, which means the frequency of sound, is increased.

2. Lower pitch sound

In this case the vehicle is moving away from the listener. The distance between and the

car is increasing. Then the listener will hear a lower pitch sound from the car, which means the

frequency of sound, is decreased. So that is the Doppler Effect in case of sound waves.

Similarly the radar unit in ACC will be continuously transmitting radio waves. They

will be reflected and echo singles (reflected waves) will be having the same frequency or

different frequency depending on speed/position of the object due to which the echo singles

originate. If the echoes singles have the same frequency it is clear that there is no relative

motion between the transmitting and receiving ends. If the frequency is increased it is clear

that the distance between the two is decreasing and if the frequency is decreased it means that

the distance is increasing.

The figure below shows a car having ACC transmitting and receiving radio waves.

In the above case, the gun transmits the waves at a given frequency toward an

oncoming car. Reflecting waves return to the gun at a different frequency, depending on how

fast the car being tracked is moving. A device in the gun compares the transmission frequency

to the received frequency to determine the speed of the car. Here, the high frequency or the

reflected waves indicate the motorist in the left car is speeding.

The embedded system is connected to the radar unit and its output will be sent to

breaking and accelerating unit as early mentioned the embedded system is a device controlled

by instructions stored in a chip. So we can design the chip or ACC having an algorithm such

that it will give output only when the input signals are less than the corresponding safe distance

value. So only when the between the car and the object in front of it is less then the same

distance value the embedded system will give output to the breaking and the accelerating units.

Thus the safe distance will be kept always. That’s how the ACC works.

ABOUT THE BEAUTY OF ADAPTIVE CRUISE CONTROL

As the driver in the next lane swerves in front of you, you feel that gas back off and

the brakes grab in the car you’ re driving- a Mercedes Benz S-class luxury vehicle, the first

passenger car equipped with a technology called adaptive cruise control. The technology

makes these adjustments even though you haven’t touched the brake or gas pedal.

At a safe distance behind, your Mercedes settles to a speed matching that of the driver

in front of you. That’s too slow, so after a look in your rear view mirror you pull into the

empty outside lane and feel the acceleration as your car speeds up to the preset cruising speed.

You still haven’t press the accelerator pedal. That’s the beauty of this racing star of the auto

industry, a millimeter- wave radar technology that promises not only to make driving easier,

but to ignite a market for gallium arsenide and other compound semi conductor components.

Although grey hound buses and some heavy- goods vehicles have been fitted with

automotive radar systems, the Mercedes is reckoned to be the first passenger automobile to

sport this advanced use of electronics, and observers say it is likely to lead a proliferation of

the technology. The Mercedes Benz system uses a 77-GHz Doppler radar linked into the

electronic control and braking system to maintain a safe distance between a car with the system

and the vehicle in front of it. Daimler Benz Aero space has completed the design of a hybrid

77-GHz radar, called Tempo mat, which is being considered for deployment.

Holger Meinel, senior researcher at Daimler Benz Aerospace AG (Ulm, Germany),

was quick to make a point stressed by all the companies working in this field. “This is not anti-

collision radar” he said. “It’s not a safety feature, it’s a comfort feature”.

The source of this distinction is concerned that if adaptive cruise control is marketed as

a safety feature, the first accident that occurs involving a vehicle equipped with millimeter-

wave radar will bring a damaging liability suit. That’s why companies are at great pains to

point out that the driver retains control and responsibility.

CONCLUSION

Most of the microprocessors in the world are not in pcs, they are embedded in devices

which control traffic for highways, airspace, railway tracks, and shipping lanes to

manufacturing systems with robots. An embedded system is any device controlled by

instructions stored on a chip. These devices are usually controlled by a microprocessor that

executes the instructions stored on a read only memory (ROM) chip. This the topic of my

seminar. Embedded systems can be used to implement features ranging from the way

pacemakers operate and mobile phone that can be worn as jewellery to adaptive cruise

control(ACC). In this seminar I will explain one such technology that uses the embedded

systems- The Adaptive Cruise Control.

ACKNOWLEDGEMENT

I express my sincere and heartfelt gratitude to

PROF: AGNISHARMAN NAMBOODIRI , Head of Department of Information

Technology and computer science , for giving me an opportunity to present this seminar. I

also express my sincere thanks to ASSISTANT PROF: SANGEETHA for providing the

expert guidance and help needed for successfully presenting the seminar and for the

completion of this report there after. I also thank profoundly, the services of Miss.

Deepa .S.S. , coordinator of seminar activities. I also thank Ms Anees Philip, Mr.Lino

Varghese, Mrs.Shajila Beegam, Department of Information Technology , for their guidance

in the presentation of this seminar.

Last but not least, I thank all of my friends who helped me for the successful

presentation of the seminar.

SHAHID MOHAMED

ABSTRACT

Most of the microprocessors in the world are not in pcs, they are embedded in devices

which control traffic for highways, airspace, railway tracks, and shipping lanes to

manufacturing systems with robots. An embedded system is any device controlled by

instructions stored on a chip. These devices are usually controlled by a microprocessor that

executes the instructions stored on a read only memory (ROM) chip. This the topic of my

seminar. Embedded systems can be used to implement features ranging from the way

pacemakers operate and mobile phone that can be worn as jewellery to adaptive cruise

control(ACC). In this seminar I will explain one such technology that uses the embedded

systems- The Adaptive Cruise Control.

CONTENTS

1. What are embedded systems? 1

2. In the driving seat 4

3. The doctor will see you now 6

4. Wired wearables 8

5. Don’t keep your eyes on the road 9

6. The working principle of Adaptive cruise control 10

7. About the beauty of Adaptive Cruise Control 13

8. Conclusion 15