CHINHOYI UNIVERSITY OF TECHNOLOGY

TITLE: INTELLIGENT EMBEDDED CONTROL

WARNING SYSTEM FOR CAR REVERSE

JOSEPH BISHI

C097139J

Table of Contents

Table of Figures ....................................................................................................................................... 2

Abstract ................................................................................................................................................... 2

Introduction ............................................................................................................................................ 3

Problem Statement .................................................................................................................................. 4

Sub Problems: ......................................................................................................................................... 4

Hardware Architecture of the car reverse system .............................................................................. 4

Software Orientated ............................................................................ Error! Bookmark not defined.

Rationale ......................................................................................................................................... 4

Objectives ........................................................................................................................................... 5

Outline Thesis: ........................................................................................................................................ 5

Scope of project ...................................................................................................................................... 6

Significance of the Study ......................................................................................................................... 6

Literature review ..................................................................................................................................... 7

1.5.1 Microcontroller .............................................................................................................................. 7

1.5.2Application of Microcontroller ....................................................................................................... 9

1.5.3 Understanding Ultrasonic .............................................................................................................. 9

1.5.4 Assembly Languages: Low-Level Language .................................................................................. 10

1.5.6 Comparison of Assembly and High Level Languages ................................................................... 11

1.6 Research Methodology ................................................................................................................... 12

Design Options: ................................................................................................................................. 12

Sensing Technique: ........................................................................................................................... 12

Proposed Approach: ............................................................................................................................. 13

Hardware Architecture ..................................................................................................................... 13

Software Implementation ................................................................................................................. 14

Results ................................................................................................................................................... 15

1.7 Delimitation of the Study ................................................................................................................ 17

Delimitations ..................................................................................................................................... 17

Conclusion ............................................................................................................................................. 17

References ............................................................................................................................................ 17

Table of Figures

Figure 1: PIC16F690 Microcontroller ..................................................................................................... 8

Figure 2: ATMEGA Microcontroller ......................................................................................................... 8

Figure 3: Basic Concepts of “ping” and “pong”..................................................................................... 10

Figure 4: Basic working structure of the car reverse system ................................................................ 14

Abstract

The focus of this projectl is to design an intelligent embedded control warning system for car

reversing. In this modern age, the focus is more on manufacturing cost effective cars that are

affordable to the average citizen. In design of nearly all technical systems, the specifications

represent a trade-off between performances and cost for example the VW Beetle versus

Mercedes Benz. The main motivation in the manufacture is the production of the best

performance that is possible for the given hardware. Under these circumstances cars like the

VW Beetle do not have sometimes if not most of the times control systems that are crucial in

the safety of the driver, other drivers, and pedestrians and also in the preservation of property

from damage due to collisions. In this project the focus is on the design of an intelligent

embedded car reversal system that is cost effective enough to be implemented in average cost

cars like the Mazda B1800. In the design of the intelligent control warning system many factors

are taken into consideration like the reliability of the system which is depended upon the choice

of the sensors in the analogous measurement of scenarios pertaining to car reversal.

Implementation of the system incorporates embedded systems technology, therefore the

design in this instance is carried out by utilisation of a microcontroller (the brains of the system),

analogue sensors to capture data from the environment, warning hardware (light emitting

diodes and buzzer).The Integrated Development Environment used is MPLAB X a product of

Microchip in the event that a pic microcontroller is used.

Introduction

The research of this paper focuses on the design of an intelligent embedded control warning

system for car reversing. The onset of technology has brought various benefits which include

automation of various instruments or tasks that were done manually previously. But with this

technology also comes problems that require solutions for a perfect balance to be achieved

between technology and its correct usage otherwise this completely nullifies the main

purpose of developing the technology. Nowadays, people are always on the run and they

sometimes forget to be cautious while backing out of a driveway, parking at work or when

trying to back out of a spot anywhere. With this, collision avoidance becomes imperative as

more than ever, the rate of accidents due to collisions during car reversals is on the rise.

Correspondingly, the number of inexperienced drivers is increasing as well and car reversal is

always a troublesome operation for them. The researcher discovered that if a person is a

physically mobile driver who is in good health, with good eyesight and a good sense of

judgment then he/she might wonder why you do ever need such a device. Many vehicles have

awkward rear visibility, or a driver might suffer problems such as neck or back injuries that

limit their ability to look over their shoulder when reversing.1Also drivers wearing varifocal

glasses while driving cannot have a perfect panoramic view while maneuvering. Even with

perfect eyesight, if the car’s rear window is quite high up then you might not spot some

obstructions, or a child or pedestrian might wander into your path without you noticing. Since

the cost of even a minor bump can be substantial, a car reversing system can be a worthwhile

investment and can give offer extra confidence to the driver when reversing.

The intelligent embedded control warning system therefore provides the apt solution to this

problem. A collision avoidance system involves three parts such as object detection, decision

making and implementing the appropriate action with regards to the decisions made. Object

detection is carried out through the use of proximity sensors. A decision-making system

makes a decision on when and how collisions can be avoided. This section relies on the

programmer as the brains behind the system. The programmer has to come up with the

algorithms that cover all scenarios of the decision making involved in car reversal. Finally,

the action taken by the system adapts the target commands generated by the previous stage

and transforms these commands to low-level control signals needed by the warning devices:

1http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/esv/esv18/CD/Files/18ESV-000466.pdf

buzzer and light emitting diodes. This paper deals with autonomous pedestrian collision

avoidance by warning the actors involved. The actors involved include the driver, pedestrian,

other drivers and inanimate objects.

Problem Statement

How can we avoid accidence when reversing? The problem is to design of an intelligent

embedded control car reversal system to reduce the occurrence of accidents due to car

reversals as vehicles being assembled in Zimbabwe and also imported Japanese only use rear

view mirrors for obstacle detection when reversing.

Sub Problems:

Hardware Architecture of the car reverse system

This section deals with the hardware involved in the implementation of the embedded system.

Note: To be dealt with in the following sections.

Hardware Architecture of the car reverse system

This section deals with the hardware involved in the implementation of the embedded system.

Note: This section dealt with in following sections.

Rationale

Fundamental reasons for designing an intelligent embedded control car reverse system:

death of infants

destruction of properties for example gates, structures.

damaging other cars usually in parallel parking

In this research, the research discovered a few factors which are causing accidents to happen

when reversing:

Factors contributing to car reverse accidents:

Some of the car’s rear window is quite high up then you might not spot some

obstructions for example Elgrand, Vans, small Lories therefore drivers fail to detect if

there is any obstacle behind the car.

Drivers tend to park in a dangerous way without thinking first.

Poor sense of judgment

Driver unable to determine the actual distance between the car and an obstacle behind

it due to eyesight problems.

There are a number of reported accidents at the Charge Office Central Police Station

of car collision mostly when reversing this is due to the increase of number of private

cars in town that correspond with limited parking spaces.

To Reference this

Objectives

The objectives of this project:

1. Design an embedded system that uses a microcontroller as the intelligence behind the

system.

2. To determine the distance between car with an obstacle behind it.

3. To inform the driver the state of car condition either they are in safe, warning or

stop zone through the colors of LEDs.

4. The system is to use a beeping buzzer sound when the car is put in reverse mode.Also

a higher and more intense sound is generated to indicate danger through a small

speaker.

Outline Thesis:

Scope of the project

Significance of the study

Literature review

Research Methodology:

Hardware architecture

Software implementation

Results

Delimitation of study

Conclusion

Scope of project

There are several scopes that need to be proposed for the project. The study targets drivers,

either male or female, who owns vehicle of this type:

Furniture company trucks (to look for the name)

Van

Small Lorries

Significance of the Study

This offers the general overview of the objectives of the project

The system introduced in this thesis can automatically measure the distance between the trail

of the car and detect the obstruction behind the car and give a sound and light alarm in real

time, ensuring the car to run safely and reduce the accident ratio. With this system, the driver

can know either he is in safe zone, warning zone or the stopping zone while reversing. If the

car is in the safe zone, a beeping is heard to warn that the car is in reversing mode. When the

car is the danger zone a sound of more intensity and volume is generated at a faster frequency

than before and LEDs start to flash at this stage to indicate danger. At this point the driver

needs to stop to avoid a collision from occurring. For application purposes this system is also

suitable for vans and small lorries. This system is set into motion when the driver engaged I

the reverse mode. It is well abstracted in such a way that the user only needs to respond to the

warnings of the system. This system offers a cost effective approach to the design of a control

system as control system are usually expensive to design, built and install. It will cut a way

through the market of the medium cars and the low-end cars and provide a new research

method for the car collision avoidance. The ultrasound sensors mounted at the back of the

car, measure the distance between the car and the object via the use of the transmitter of the

ultrasound sensor. The transmitter transmits ultrasonic signal while the receiver receives the

reflected wave, and the sound wave transmitting time and the distance are in direct ratio, so

the function of distance measurement is obtained.

Literature review

1.5.1 Microcontroller

A microcontroller (MCU) is a small computer on a single integrated circuit containing a processor

core, memory, and programmable input/output peripherals. Program memory in the form of NOR

flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM. The

microcontroller includes a CPU, RAM, ROM, I/O ports, and timers like a standard computer,

but because they are designed to execute only a single specific task to control a single system,

they are much smaller and simplified so that they can include all the functions required on a

single chip. A microcontroller differs from a microprocessor, which is a general-purpose chip

that is used to create a multi-function computer or device and requires multiple chips to

handle various tasks. A microcontroller is meant to be more self-contained and independent,

and functions as a tiny, dedicated computer.

The great advantage of microcontrollers, as opposed to using larger microprocessors, is that

the parts-count and design costs of the item being controlled can be kept to a minimum. They

are typically designed using CMOS (complementary metal oxide semiconductor) technology,

an efficient fabrication technique that uses less power and is more immune to power spikes

than other techniques. Early controllers were typically built from logic components and were

usually quite large. Later, microprocessors were used, and controllers were able to fit onto a

circuit board. Microcontrollers now place all of the needed components onto a single chip.

Because they control a single function, some complex devices contain multiple

microprocessors.

Examples of microcontrollers include the Microchip series of microcontroller which is the

PIC range. Another range of microcontrollers is the ATMEGA microcontroller series by the

chip manufacturing company ATMEL.

Figure 1: PIC16F690 Microcontroller2

Figure 2: ATMEGA Microcontroller3

2http://www.piccircuit.com/shop/483-large/pic16f690-i-p-pdip.jpg

3http://4.bp.blogspot.com/_83WgROTnvFo/SQNSNlb0DqI/AAAAAAAAAMw/Xjth_gxDkfk/s320/atmega8.png

1.5.2Application of Microcontroller

Microcontrollers are designed for embedded applications, in contrast to the microprocessors

used in personal computers or other general purpose applications. Microcontrollers are used

in automatically controlled products and devices, such as automobile engine control systems,

implantable medical devices, remote controls, office machines, appliances, power tools, toys

and other embedded systems. By reducing the size and cost compared to a design that uses a

separate microprocessor, memory, and input/output devices, microcontrollers make it

economical to digitally control even more devices and processes. Mixed signal

microcontrollers are common, integrating analog components needed to control non-digital

electronic systems.Microcontrollers are typically used where processing power is not so

important. The small size, low power consumption, and flexibility make these devices ideal

for unattended data monitoring and recording.

1.5.3 Understanding Ultrasonic

Ultrasound is an acoustic wave with a very high frequency, beyond human hearing. Since the

audible frequency range is said to be between 20Hz and 20kHz, ultrasound generally means

acoustic waves above 20kHz.The ultrasonic transducers have piezoelectric crystals which

resonate to a preferred frequency and convert electric energy into acoustic energy and vice

versa (Watson, 2006).It is used for calculating the distance and/or direction of an object from

the time it takes for a sound wave to travel to the target and back. An ultrasonic sensor is a

speaker or microphone that emits or receives ultrasound. There is also a type that can handle

both emission and reception. For vehicle reversing, the sensors are equipped with this type of

sensor. In the case of the rear sonar, two to four ultrasonic sensors are mounted on the rear

bumper to detect an obstacle up to 2 to 2.5m away. The distance is communicated to the

driver in real time by lighting different colors of LEDs and varying the type of sound

produced at each stage.

The illustration in Figure 1 shows how sound waves, transmitted in the shape of a cone, are

reflected from a target back to the transducer. An output signal is produced to perform some

kind of indicating or control function. A minimum distance from the sensor is required to

provide a time delay so that the "echoes" can be interpreted. Variables which can affect the

operation of ultrasonic sensing include: target surface angle, reflective surface roughness or

changes in temperature or humidity. The targets can have any kind of reflective form - even

round objects.

Figure 3: Basic Concepts of “ping” and “pong”

When used for sensing functions, the ultrasonic method has unique advantages over

conventional sensors such as infrared or reverse sensor (Larson, 1960):

a. Discrete distances to moving objects can be detected and measured

b. Less affected by target materials and surfaces, and not affected by color. Solid state

units have virtually unlimited, maintenance free life. Have ability to detect small

objects over long operating distances

c. Have resistance to external disturbances such as vibration, infrared radiation, ambient

noise, and EMI radiation.

1.5.4 Assembly Languages: Low-Level Language

An assembly language is a low-level language for programming computers. It implements a

symbolic representation of the numeric machine codes and other constants needed to program

a particular CPU architecture (David Salomon, 1993). This representation is usually defined

by the hardware manufacturer, and is based on abbreviations (called mnemonics) that help

the programmer remember individual instructions, registers, etc.Assembly languages were

first developed in the 1950s, when they were referred to as second generation programming

languages. They eliminated much of the error prone and time-consuming first-generation

programming needed with the earliest computers, freeing the programmer from tedium such

as remembering numeric codes and calculating addresses. They were once widely used for all

sorts of programming. Today, assembly language is used primarily for direct hardware

manipulation, access to specialized processor instructions, or to address critical performance

issues. Typical used on device drivers, low-level embedded systems, and real-time systems.

A utility program called an assembler is used to translate assembly language statements into

the target computer's machine code. The assembler performs a more or less isomorphic

translation (a one-to-one mapping) from mnemonic statements into machine instructions and

data. (This is in contrast with high-level languages, in which a single statement generally

results in many machine instructions. A compiler, analogous to an assembler, is used to

translate high-level language statements into machine code; or an interpreter executes

statements directly.) Many sophisticated assemblers offer additional mechanisms to facilitate

program development, control the assembly process, and aid debugging.

1.5.6 Comparison of Assembly and High Level Languages

Assembly languages are close to a one to one correspondence between symbolic instructions

and executable machine codes. Assembly languages also include directives to the assembler,

directives to the linker, directives for organizing data space, and macros. Macros can be used

to combine several assembly language instructions into a high level language-like construct

(as well as other purposes). There are cases where a symbolic instruction is translated into

more than one machine instruction. But in general, symbolic assembly language instructions

correspond to individual executable machine instructions.

High level languages are abstract. Typically a single high level instruction is translated into

several (sometimes dozens or in rare cases even hundreds) executable machine language

instructions. Some early high level languages had a close correspondence between high level

instructions and machine language instructions. For example, most of the early COBOL

instructions translated into a very obvious and small set of machine instructions. The trend

over time has been for high level languages to increase in abstraction. Modern object oriented

programming languages are highly abstract and offer data abstraction. In relation to this

project it is advisable to use high level languages like C as they are easier to implement than

using assembly language. To use assembly language one will need to learn the instruction

manual/datasheet pertaining to the microcontroller.

1.6 Research Methodology

This section of the research paper highlights as to how the project is going to be carried.

Various methods can be implemented in the design process of the project.

Design Options:

Basically the concept behind the design is almost the same for the intelligent embedded

control car reversal system. The components that are repeated in all the designs are as

follows:

Control system(usually a microcontroller or some embedded system)

Sensors for detecting the environmental conditions in this case the proximity of an

object from the car

Interface components for example buzzer, LEDs.

As the design options are almost the same, I will look at the areas where they differ that are

the type of sensors used and the warning devices used. Also in this project a test mobile is not

being used, in other designs it is used to simulate the behaviour of a real car in application.

Sensing Technique: Sensing technique is one of the most important concerns inorder to accomplish an accurate and

energy-efficient detectionscheme. Thus it is necessary to find an optimal sensor that gives better

range, accuracy and response as the system being designed is a real time system(dependent on the

time response of the system).

Types of Sensors that can be used

Infrared sensors

Too sensitive. Can be used instead of ultrasound as they offer better performance

compared to other sensors.

Temperature sensors

Not applicable as they are not able to detect an object.

Camera.

This sensor utilizes vision of the object in question. The main drawback of using this

type of sensor is that for accurate performance it requires use with other sensors and it

is expensive to use, thereby running away from the objective of producing a cost

effective system.

Ultrasound sensors

Detection is easy and they are reliable.

Interfacing components:

LCD display

This is expensive to setup in the system. LCD displays are expensive

LEDs

Very cheap to use. But in the case of the digital LED display, that is more expensive.

Buzzer/speaker

Very cheap

Human voice technology

It costs to install this kind of technology

Proposed Approach:

Hardware Architecture List of components to be used

Resistors for limiting current to the buzzer and/speaker(so as not to pass too high a sound)

Capacitors for filtering the sound to the speaker

LEDS in the following colors: green, yellow and red. These are used for safe duration of car

reversal, warning stage and dangerous stage. warning the

Microcontroller (can be an ATMEGA or a PIC series microcontroller).All the components will

be connected to the microcontroller. The ultrasound sensors are connected as analogue

input to the microcontroller. The LEDs, buzzer and speaker are connected as outputs.

Ultrasound sensors: transmitter and receiver. These will be placed at the back of the car for

the purpose of object detection while reversing.

Breadboard/Vero Board on which to build the circuit

5V batteries to power the circuit

Jumper wires/connectors to connect each and every circuit connection

Buzzer and speaker, generate sound during car reversing and for warning.

Tools to be utilized in the implementation stage:

Programmer to program the microcontroller

IDE(Integrated Development Environment) for example MPLAB X( for pic series

microcontrollers) and AVR( for the ATMEGA series of microcontrollers)

Figure 4:Basic working structure of the car reverse system

Software Implementation Overall Algorithm for implementing the control system:

The algorithm of the system is relatively simple.

A method and apparatus for object detection and ranging is disclosed. A returned signal is

sequentially received by the sensors mounted on a host vehicle. It in turn initiates successive

sampling to collect a series of returned signal values, which is then compared with corresponding

threshold value previously saved in a memory device (microcontroller) to determine whether any

object is in the way of the vehicle backing up and also to estimate the relative distance from the

object. The control circuit in accordance with the invention includes a processor, which together

with a channel selector establishes a sequence of signal transmission and reception each time by

sensors. A sampled signal is first passed through and A/D (Analogue to Digital) converter to become

digital, and then it is input to the processor for object detection and ranging computation. After this

depending on the distance from the vehicle, the LEDs, buzzer and speaker are sounded accordingly.

*Note: Flow diagram of the algorithm shown on the next page due to its size.

Microcontroller Ultrasound

Sensor

transmitter

Ultrasound

Sensor

receiver

transmitter

Object

Buzzer

LED LED LED

Speaker

Battery

Results

The results on the system include experimental tests on the system components.

Components tests

These are carried out to find out if all the components are working properly as components have a

tendency to fail due to various reasons.

Examples of tests at interim stage:

Tests done on the microcontroller to ensure that all its pins are working

Tests done on the buzzer and speaker to tests whether they output sound

Tests done on the LEDs to see if they light properly and are not releasing faint light or are

not burnt out.

Testing the ultra sound sensors to see whether they are transmitting and receiving the

ultrasound signal.

Tests on the power, in this case can use batteries to power the system

Cars reverse Control System tests:

These tests are yet to be done as implementation of the project has not yet started.

Figure 5:Flow diagram of the object detection algorithm

Predetermine compensation and threshold distance

Once car reversal radar starts, the ultrasonic sensors

start sending out ultrasonic waves for object detection

Obtain initial sensing results

Convert initial sensing results into initial sensing values

and store them in the memory unit (microcontroller)

Convert the subsequent sensing results into subsequent

sensing values and store them in a memory unit.

Continuously detect obstacles and obtain subsequent

sensing results.

Is any of the subsequent sensing

value > than the sum of the initial

sensing value and the

corresponding compensation

value?

Determine that an object is detected

Compute the actual distance between the object and the ultrasonic sensor

Determine that

no obstacle

detected

NO

YES

Determine whether the actual distance

between the obstacle and the ultrasonic

sensor is > than the threshold distance

Increase the

compensation values

The CPU drives the warning

module to warn the driver

YES NO

1.7 Delimitation of the Study

Delimitations

The study will not consider exported cars that already have the intelligence like Lexus 570,

Range Rover etc. The system will not go into mechanical aspect but it will only cover the

embedded control system aspects where the researcher is only going to design a control

warning embedded system which utilises a microcontroller and proximity sensors for

distance measurement and the corresponding warning/alarm devices. The system can become

very expensive if other object detection sensors like cameras are implemented and also if

hardware for example the LCD are used for displaying purposes of the project. Other

limitations arise from the accuracy and range of the hardware itself. Ultrasound sensors have

a range of detection and therefore if the range is exceeded can result in loss of accuracy in the

system. Methods that improve the sensors’ range can therefore be employed.

Conclusion

This research paper presented the proposal for an intelligent embedded control car reverse

system. The intelligent system consists of components that will help drivers overcome car

reversal accidents. The deployment of the car reversal system will reduce the number of

accidents while reversing. Consequently this also reduces the damage to property, injuries

and death due to car reversing.

References

[1]http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/esv/esv18/CD/Files/18ESV-000466.pdf

[2]http://www.piccircuit.com/shop/483-large/pic16f690-i-p-pdip.jpg

[3]http://4.bp.blogspot.com/_83WgROTnvFo/SQNSNlb0DqI/AAAAAAAAAMw/Xjth_gxDkfk/s320/atm

ega8.png

[4] http://www.newelectronics.co.uk/electronics-technology/an-introduction-to-ultrasonic-sensors-

for-vehicle-parking/24966/

[5] http://www.princeton.edu/~amitabhg/papers/CTS-2008.pdf