Design of Ultrasonic Alarm System
Content
ABSTRACT
This alarm system is created to detect an object movement in the coverage area. Alarm will trigger when object movement is detected. Nowadays, a lot of crimes happened in o w life. The idea for this alarm project came out through the total of frustration when there is no other ways to stop burglary from break-in into the house, shop or car. Of course safety was the prime concern of the security system companies. However, house owners cannot rely on neighbours or police for protecting their home or warning them if a break-in has occurred in progress. To overcome this problem, an ultrasonic security system has been developed in this project. The system has a sensor that can detect an object movement in the covered
area This project consists of 6 parts of circuit which is the power supply circuit, the
battery indicator circuit, the ultrasonic sensor circuit, the alarm circuit, the remote control circuit and the LCD display circuit. The power supply circuit produces and supply the 12V and 5V voltages. The battery indicator circuit is used to show the level of energy in the battery. The battery will act up if something happen to the power supply such as blackout. Ultrasonic sensor circuit has a transmitter circuit and the receiver circuit that operate at the same fkquency level namely 40 MIz. When there's a movement in the area covered by the circuit, the circuit's fme balance will be disturbed, thus trigger its alarm. The circuit is very sensitive and can be adjusted automatically or to stay triggered until it is reset manually after an alarm. Actually, this project use low costs budget and it is suitable for commercial used. From this project, found that the maximum distance that ultrasonic sensor can detect the object movement is 3.5 meters and for the sensitivity, it depend the environment factors such as air and noise.
ABSTRAK
Sistem Penggera ini direka untuk mengesan sebarang objek yang bergerak didalam kawasan yang diliputi oleh sistem ini. Penggera akan berbunyi sekiranya terdapat sebarang pergerakan objek yang dikesan. Pada masa kini, terdapat banyak kejadian jenayah yang berlaku di sekeliling kita Idea untuk membuat projek ini terhasil apabila sudah tiada jalan untuk menyekat perompak atau pencuri daripada
n menceroboh rumah, kereta dan juga kedai. Oleh yang demikian, projek ii
merupakan salah satu altematif untuk mengatasi masalah berikut. Sudah semestinya, aspek terpenting yang dititik beratkan dalam sistem keselamatan m e ~ p d c a n
n. keselamatan ii Tambahan pula, pemilik rumah, kereta dan kedai tidak boleh
mengharapkan jiran-jiran dan polis sahaja mefindunpi atau mengelakkan rumah, kereta dan kedai daripada diceroboh. Sebagai penyelesaian kepada masalah ini, sistem keselamatan ultrasonik direka dalam projek ini. Sistem i mempunyai n i pengesan yang mengesan pergerakan objek dalam ka yang mampu diliputi oleh sistem tersebut. Projek ini mengandungi 6 bahagian litar yang terdiri daripada litar kawalan jauh, litar bekalan kuasa, litar penunjuk paras bateri, litar pengesan ultrasonik, litar penggera dan litar untuk paparan 'LCD'. Litar bekalan kuasa berfungsi untuk menghasilkan voltan pada 12V dan 5V.Litar penunjuk paras bateri pula berfungsi untuk menunjukkan paras tenaga di dalam bateri yang digunakan. Bateri ini juga bertindak sebagai bekalan kuasa simpanan jika sesuatu terjadi kepada litar bekalan kuasa tersebut seperti terputus bekalan dan sebagainya. Litar pengesan ultrasonik mempunyai litar pemancar dan penerima yang beroperasi pada fkekuensi yang sama iaitu 40kHz. Apabiia terdapat sebamng pergerakan yang akan menyebabkan kestabilan litar terganggu, maka sistem penggera akan dihidupkan. Litar ini sangat sensitif dan boleh dilaraskan secara autornatik atau terus dipicu sehingga ia dilaraskan secara manual. Projek ini menggunakan kos yang rendah dan ia sangat sesuai untuk dipasarkan secara komersial. Selepas projek ini disiapkan dan
vii melalui analisis yang dibuat terhadap sistem penggera ini didapati bahawa pengesan ultrasonik mampu mengesan objek sehingga pada jarak 3.5 meter. Selain i N didapati juga faktor-faktorpemkitaranjuga memainkan peranan yang penting dalam mempengaruhi kesensitifan litar seperti udara dan hingar.
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND
This alarm system use an ultrasonic sensor to detect the object movement in the covered area The ultmsonic sensor was chosen because it's more compatible and appropriate for this alarm system. The features are better than i h - r e d sensor. The main factors ultmwnic sensor was chosen is, it will not infected by any type of material and color at object that has been detected. It also able to detect the small object and not infected by dust, dirt and humidity. Thus, this is also an advantage using the ultrasonic sensor. Ultrasonic sensor also has a weakness and disadvantage that is the sensor can't be installed at area that has high air flow and high noise. Actually, the ultrasonic sensor is a main component in this alarm system. Besides
that,this alarm system also combined with another circuit where this other circuit is
used as supporter to the ultrasonic sensor circuit. For ultrasonic sensor, it has 2 types of kquencies in the market namely 40 kHz and 10 MHz where for 40 kHz, it can detect up to 5 meter. Where else, for IOMHz, it capable to detect until 10 meter but the price is very expensive. As a result, for this alarm system the sensor that uses 40
kHz is more effective and appropriate.
This project has objectives that require to achieve. At the end of project, all of objectives that list are satisfied or covered. The objectives of this project are listed as below. a) To design an alarm system that capable of detecting movement object. b) Understand the operation of the circuit and applications of this alarm system. c) To know how to simulate the circuit by using the appropriate softwares. d) To improve the skills and techniques for making or designing the hardware.
1 3 PROJECT SCOPE
The scope of this project is using an ultrasonic sensor to detect the movement
ranging and detecting devices used a high-fkquency sound wave object. ~ l t r a k n i c
namely 40 kHz to detect the presence of an object.
Else, this project capable to detect object in distance about 5 meters. This is a
maximum distance that ultrasonic sensor can detect if using 40 kHz fkquency. So, in
this distance, the ultrasonic sensor can detect the movement object and trigger alarm immidiately.
1.4 PROBLEM STATEMENT.
Firstly, using the security guard is not effective and increases the cost. It cause the security guard not capable to monitor the area for 24 hours. Else, the security guard need paid the salary for every month. So, it will increase the cost for monitor the area that required.
Second, high cost required to install the security system that sophisticated. To install the security system that sophisticated, it need a high cost. So, the sophisticated security system only can install by persons that have a ability. For persons that haven't ability to install it because it need a high cost.
Third, nowadays, there have much a criminal that happen especially stealing, intrusion and something like that. The house owners usually don't know that the robbers have inside their house and not prepare to avoid them from steale.
1.5 PROJECT METHODOLOGY.
This project divided into hardware and software application.
1.5.1
Software application.
For software application, compiler software used is The PIC Basic Pro Compiler and the programmer software used is IC-Prog. For the Code Editor, it used the Microcode Studio. So, the programs can wrote and edited in Microcode Studio. It has a few steps to get the machine code (Hex) for the data to program in the microcontroller. Figure below show the process done with the software to get the .hex file.
Programming
Microcode Studio
Compiling
ICProgramming
To interface circuit
I I I
PIC Basic Pro
IC-Prog
Figure 1.1 : PIC microcontroller programming process and software that used.
1.5.2 Hardware application.
Such as software application, this part also has some steps that need to follow. Firstly, do the research and understand the concept of 'alarm system'. Information collected are regarding with PIC, 'alarm system' concept. Through this method, information that had collected previously is researched consistent with the objective of the project. Through this method, concept and principle for the project will be studied to produce the ideas for this project.
Second, the flow chart is build where this flow chart is used to show the steps that need to follow before the project is implemented. The flow chart is planned and built and this flow chart also consist ways for this project to operate and to controlling. Third, the circuit is designed. The circuit is design using a software of 'ORCAD 10.0'.
The fourth step is do the circuit simulation. The designed circuit is simulated
by using software of 'Proteus ISIS 6 Profesional' or ' E m Cicuit Maker'. By this
method, the operation of circuit can be inspect wheather the circuit has problem or not and if any, the improvement can implement.
The f f h step is build a prototype for the project. Prototype is built when the it circuit simulated is function and has no problem. It's built on the 'protoboard'. This prototype is built to test wheather the circuit has a problem or not. The improvement
can implement if the circuit designed has a problem.
The sixth step is design the 'PCB Layout'. If the circuit designed has no problem, next, the 'PCB Layout' is designed by using software of 'Protel' or 'Proteus ISIS 6 Profesional'. This method is did by full concentration to avoid a something mistake that will give difficulty when to assemble the component.
The seventh step is design the 'PCB'. The completed PCB Layout will be printed on the PCB board and drilling hole on the PCB will be done. The last step is install the component on the PCB board. Component is installed on the PCB board
i that has completed follow the circuit that has designed previously. P of component
is cut and soldered. Soldering equipment is required during this process.
Circuit Design
fail
IC Programming
Check wiring
I
Construct on PCB
Check PCB
Figure 1.2 : Flowchart of the process of designing the project.
1.6
PROJECT OVERVIEW.
Alarm System is circuits that capable to detect the moving objects as an input
and the output is alarm where alarm will trigger when detect the moving object. The ultrasonic sensor is choosing because it capable to detect the moving object up to 5 meters for 40 kHz sensor and remote control is required to wntrol this circuit. Thus, user can control the alarm system from certain distance that is about 10 meters.
Basically, this project consists of hardware and software programming, the hardware such as power supply circuit, remote control circuit, ultrasonic detector circuit, battery indicator circuit, LCD display circuit and alarm circuit.
Power Supply
t
Remote Control
Battery Indicator
1
Uk~~i~onic Detector
I
Alarm
LCD Display
Figure 1.3: Block diagram of project.
Structurally, the circuit consists of six parts: power supply circuit, battery indicator circuit, remote control circuit, ultrasonic detector circuit alarm circuit and LCD display circuit. Power supply circuit will produce 12V and 5V where it will supply the voltage to remote control circuit and ultrasonic circuit. Battery indicator circuit will show status of the battery in the power supply. Remote control circuit will control the ultrasonic detector circuit for 'ON' and 'OFF'. Alarm circuit will
trigger the alarm when sensor detects the moving object. LCD display circuit will display the output from ultrasonic detector circuit. So, input of this alarm system is from sensor and the output is alarm and LCD display. PIC is used to control the
alarm circuit and LCD display circuit. The program is in PIC Basic Pro format. This
format is used because it short and easy to build. The discussion about the program is review in next chapter.
At the last, the result from this project is the ultrasonic sensor able to detect the moving object. An alarm will trigger when moving object is detected. Else, remote control circuit able to control the ultrasonic detector circuit for 'ON' and
'OFF'.
CHAPTER 2
LITERATURE REVIEW
2.1 INTRODUCTION
This alarm system circuit has parts or elements namely the Ultrasonic Sensor,
Remote Control, PIC microcontroller and Battery. Ultrasonic sensor is the main element for this project because this sensor is used to detect any object movement around the area that is covered by this circuit. Besides that, a remote control is used to control the ultrasonic sensor circuit where it can control namely on and off the ultrasonic circuit in the distance of 10 meters. The PIC microcontroller is used to control the display of the LCD and control the alarm circuit. The types of PIC microcontroller used are 16F84A. The battery is used as back-up when something happen to the electricity. The ability to maintain the regulated supply with no electrical supply depends on the load taken from the UPS and also the Ampere how capacity of the battery.
10
2.2 ULTRASONIC SENSOR
2.2.1 An Introdnction to Ultrasonic Sensing
Ultrasonic ranging and detecting devices used a high-frequency sound wave to detect the presence of an object and its range. The systems either measure the echo reflection of the sound from objects or detect the interruption of the sound beam as the objects passed between the transmitter and receiver.
Ultrasonic sensors are commonly used for a wide variety of non contact presence, proximity, or distance measuring applications. These devices typically transmit a short burst of ultrasonic sound toward a target, which reflects the sound back to the sensor. The system then measures the time for the echo to return to the sensor and computes the distance to the target using the speed of sound in the medium.
Figure 2.1 : The 40 KHz Ultrasonic Sensor
The wide variety of sensors currently on the market differs from one another in their mounting configurations. Environmental sealing and electronics features. Acoustically, they operate at different frequencies and have different radiation pattern. It is usually not difficult to select a sensor that best meets the environmental and mechanical requirement for a particular application, or to evaluate the electronic features available with different models. Still, many users may not be aware of the acoustic subtleties that can have major effects on ultrasonic sensor operation and the measurement W i g made with them.
2.23 Selection of Ultrasonic Sensor.
Here we come to the section that can help user to select an ultrasonic sensor with the best acoustical properties, such as frequency and beam pattern, for a particular application, and how to obtain an optimum measurement fiom the sensor. The first step in this process is to gain a better understand'ig of how variations in the acoustical parameters of both the environment and the target affect the operation of the sensors. Specifically, the following variable will be discussed namely variation in the speed of sound as function of both temperature and the composition of the transmission medium, usually air, and how these variations affect sensor measurement accuracy and resolution.
Variation in the wavelength of sound as a function of both sound speed and frequency, and how this effect the resolution, accuracy, minimum target size, and the minimum and maximum target distances of an ultrasonic sensor. Variation in the attenuation of sound as a function a both frequency and humidity, and how this affects the maximum target distance for an ultrasonic sensor in air. Variation of the amplitude of background noise as a function of frequency and how it can effects the maximum target distance and minimum target size for an ultmmnic sensor. Variation in the sound radiation pattern (beam angle) of both the ultrasonic transducer and the
complete sensor system, and how this affects the maximum target distance and helps eliminate extraneous target. Variation in the amplitude of the return echo as a function of the target distance, geometry, surface and size, and how this affects the maximum target distance attainable with and ultrasonic sensor.
2.2.3 Ultrasonic Motion Detectors.
Ultrasonic motion detectors can be used to detect motion in an area where there are supposed no any moving objects. This type of motion detector is most commonly used in burglar alarm systems since they are very effective in this application.
Figure 2.2 : Ultrasonic motion detector
Figure 2.2 shows the operation of an ultrasonic motion detector. There are
mt two transducers: one e i s an ultrasonic wave and the other picks up reflections from
the different objects in the area. The reflected waves arrive at the receiver in constant phase if none of the objects in the area are moving. If something moves, the received signal is shifted in phase. A phase comparator detects the shifted phase and sends a triggering pulse to the operation motor.
2.2.4 Transducer Configurations.
A transmitting transducer sends out a pulse of sound that is detected by a
receiving transducer. Figure 1 shows several types of transducer coniigurations. Two transducers are mounted side by side. In this application, ultrasonic energy from the transmitter is reflected by an object and the echo is detected by the receiving transducer. This system measures the elapsed time from when the sound pulse is transmitted to when the echo is detected to determine the exact range of the object from the transducers. The application differs only in that a single transducer is used to transmit the sound pulse and receive the echo.
In some applications, such as high-speed counting and mechanical equipment positioning, it may be desirable to position the transducers opposing each other. For clarity, the term "sensor" will be used in this article to describe either a single or dual transducer configuration [5].
2.25 Beam Angles and Side Lobes.
Ultrasonic transducers are often designed to be directional so that the sound is efficiently transmitted or received only over a certain conical beam angle in fiont of the sensor. Ultrasonic transducers can be designed to produce any beam angle desired, from narrow (with beam widths of a just few degrees) to virtually omni directional. Some narrow beam transducer designs produce side lobes as the sound energy is transmitted. Advanced transducer designs eliminate all secondary side lobes and are more desirable for ultrasonic echo ranging.
Different applications may require different beam angles for the sensors. In most cases, however, narrower beam angles are usually preferable to broader ones. A narrow beam angle system will not detect unwanted objects that are not in the insonified path of the transducer. (To insonify means to fill a specific volume with sound from a transducer). Namw beam angle systems are also less susceptible to background ultrasonic noise, and the systems will also operate over a greater range.
The beam angle of a transducer, alpha, is defined as the total angle between the points at which the sound power has been reduced to half its peak value. These
are commonly referred to as the 3 dB down points. It is often advantageous to
compute the spot diameter that is insonifid by the ultrasonic beam.To calculate this spot diameter, use the formula: D = 2 * R * tan(O.5 * alpha) Where : D = spot diameter in inches
R = target range in inches
alpha = total beam angle in degrees
sound travels through air, its energy attenuates more rapidly if the frequency is increased. The maximum theoretical attenuation for ultrasonic sound (up to 200 kHz) may be calculated by this formula:
amax = f * 10-2
(2.4)
where:
amax =maximum attenuation in dB/fi
f = frequency in kHz
For example, using this equation, sound energy from a 215 kHz transducer would be attenuated a maximum of 2.15 dl3/ft as it traveled through air. Attenuation may be less, depending on humidity, but is not so easily defined or calculated. Although attenuation limits the range of higher frequency transducers, there is a bonus: background noise at the same higher frequency is also Iess. Higher frequency ultrasonic sensors therefore, have a much better chance of working in an acoustically noisy environment than do lower frequency sensors. Beam angle also helps to lower background noise interference by limiting the transducer's noise sensitivity to the area defined by the beam angle of the sensor. Some transducer designs utilize a detachable horn. When the horn is attached, the beam angle of the transducer is reduced. This concentration of acoustical energy into a tighter beam increases the range of the sensor and reduces the background noise as well.
2.2.7 Environmental Factors
2.2.7.1 Temperature.
The velocity of sound in air is 13,044 in./s at 0 C; it is directly proportional to air temperature. As the ambient air temperature increases, the speed of sound also increases. Therefore if a fixed target produces an echo after a certain time delay, and if the temperature drops, the measured time for the echo to return increases, even though the target has not moved. This happens because the speed of sound decreases, returning an echo more slowly than at the previous, warma temperature. If varying ambient temperatures are expected in a specific application, compensation in the system for the change in sound speed is recommended.
2.2.7.2 Air Turbulence and Convection Currents.
A particular temperature problem is posed by convection currents that contain many bands of varying temperature. If these bands pass between the sensor and the target, they will abruptly change the speed of sound while present. No type of temperature compensation (either temperature measurement or reference target) will provide complete high-resolution correction at all times under these circumstances. In some applications it may be desirable to install shielding around the sound beam to reduce or eliminate variations due to convection currents. Averaging the return times h m a number of echoes will also help reduce the random effect of convection currents. Users addressing applications requiring high accuracy and resolution should evaluate these suggestions carellly.
2.2.7.5 Acoustic Interference.
Special consideration must be given to environments that contain background noise in the ultrasonic frequency spectrum. For example, air forced through a nozzle, such as air jets used for cleaning machines, generates a whistling sound with harmonics in the ultrasonic range. When in close proximity to a sensor, whether d i t e d at the sensor or not, ultrasonic noise at or around the sensor's frequency may affect system operation. Typically, the level of background noise is lower at higher frequencies, and narrower beam angles work best in areas with a high ultrasonic background noise level. Often a baffle around the noise source will eliminate the problem. Because each application differs, testing for interference is suggested.
2.2.7.6 Radio Frequency Interference.
Another possible source of noise is RFI emitting from SCRs in a variable speed drive. Shielding around the back and sides of the transducer may prevent RFI noise from entering the system.
2.2.7.7 Splashing Liquids.
Splashing liquids should be kept from striking the surface of the sensor, both to protect the sensor from damage if it is not splash proof and to ensure an open path for the sound energy to travel. Sensors used in a splashing environment, however, should be designed to operate when wet.
Mounting orientation is also a consideration in such an environment. Straightdown orientation can cause moisture to form as a large drop on the face of the sensor, reducing the efficiency of the system. Certain applications permit mounting the sensor so that it is aimed lower than horizontal but not pointed straight down; in this orientation, gravity will help to keep moisture h m collecting on the face of the sensor.
Two methods may be used to improve the reliability of ultrasonic in the presence of splashing liquids. While beam bouncing provides a clever way of keeping the sensor out of the immediate area of splashing liquids, some applications don't lend themselves to this technique. An alternative method involves placing around the sensor a short tube that extends out past its face but not into the actual
beam pattern. It is very important that the acoustic beam not be allowed to touch the
edge of the tube; if it does, the tube might deteriorate the acoustic performance.
2.2.8 Target Considerations.
2.2.8.1 Composition.
Nearly all targets reflect ultrasonic sound and therefore produce an echo that can be detected. Some textured materials produce a weaker echo, reducing the maximum effective sensing range. The reflectivity of an object is often a function of fkquency. Lower fkquencies can have reduced reflections &om some porous targets, while higher frequencies reflect well from most target materials. Precise performance specifications can often be determined only through experimentation.
2.2.8.2 Shape.
A target of virtually any shape can be detected ulhasonically if sufficient echo returns to the sensor. Targets that are smooth, flat, and perpendicular to the sensor's beam produce stronger echoes than irregularly shaped targets. A larger target relative to sound wavelength will produce a stronger echo than a smaller target until the target is larger than approximately 10 wavelengths across. Therefore, smaller targets are better detected with higher frequency sound. In some applications a specific target shape such as a sphere, cylinder, or internal cube comer can solve alignment problems between the sensor and the target.
2.2.8.3 Target Orientation to Sensor.
To produce the strongest echoes, the sensor's beam should be pointed toward the target. If a smooth, flat target is i n c l i i off perpendicular, some of the echo is deflected away from the sensor and the strength of the echo is reduced. Targets that
are smaller than the spot diameter of the transducer beam can usually be inclined
more than larger targets. Sensors with larger beam angles will generally produce stronger echoes from flat targets that are not perpendicular to the axis of the sound
beam. Sound waves striking a target with a coarse, irregular surface will diffise and
reflect in many d i i o n s . Some of the reflected energy may return to the sensor as a
weak but measurable echo. As always, target suitability must be evaluated for each
application.
2.2.8.4 Averaging.
Certain applications involve a constantly moving target, such as the surface of agitated liquid in a tank. Analog outputs, which may be averaged by a Programmable Logic Controller or computer, will track the constant movement with
un little difficulty, but set point outputs might t r on and off unnecessarily as the target
hovers around a set point distance. Hysteresis will prevent switched outputs from oscillating to a certain extent, but if the agitation or movement is great enough, the outputs will still switch on and off.
This problem can be easily solved in a number of ways. One method is to delay the decision process by using a time delay relay (TDR). A DC powered ondelay TDR may be directly connected to a set point output and programmed to delay switching on its output u t l it has received power for a specific length of time. The ni target will then have to be past the set point distance for that programmed time before the TDR will turn on, activating the primary load. Measurement can also be averaged with a Programmable Logic Controller (PLC) or an averaging digital panel meters. PLCs have done for industrial control what word processing has done for the modem office--they have provided flexibility and have reduced costs by greatly simplifying the wiring and troubleshooting of a complete process system.
Ultrasonic systems have also increased the flexibility of measurement and control systems used in typical applications. One ultrasonic system can often replace multiple photoelectric, capacitive, or mechanical l i t switches and at the same time provide additional distance information. The fact that all measurements are made without physical contact with the target improves the lives of both the target and the sensing system.
2.3 PIC MICROCONTROLLER
23.1 What is a Microcontroller?
A computer revolution in the last 15 years has produced computer with very
high speeds and computing power while keeping their sizes compact. This revolution has occurred as a result of a development of Large-scale Integration (LSI) and Very Large-scale integration (VLSI) technologies, which put tern s of thousands of transistor on a single chip. This has made in possible to fabricate the heart of a microcomputer as a single chip called a microprocessor (h4F'U). This chip, with additional auxiliary chips called peripherals, constitutes 'a microcomputer'. Such peripherals are VO ports, memories, timers and so on.
The new technology has also made it possible to integrate this microprocessor and its peripherals in a single chip called a microcontroller (MCU) That is the reason a microcontroller is called a single-chip microcomputer.
23.2 Why Use a Microcontroller?
Microcontroller is inexpensive. The microcontroller's ability to store and run unique programs makes it extremely versatile. For example, we can program a microcontroller to make decision (pelform functions) based on predetermined situations (VO line logic) and selections. The microcontroller's ability to perform math and logic functions allows it to mimic sophisticated logic and electronic circuit. Other program can make the microcontroller behave l i e a neural circuit andfor a
fuzzy logic controller. Microcontroller is responsible for the "intelligence" in most
smart devices on the consumer market.
The are literally hundreds of microcontrollers on the market. Listed here are some of the popular 8-bit microcontroller and their features 121. These devices are the lowest cost representative devices fiom respective manufactures.
Table 2.1: Some 8-bit microcontroller s and their features. COMPANY Atmel DEVICE Attiny I1 ON-CHIP MEMORY 1-Kbyte flash 8-bit timer, analog comparator, watchdog, onchip oscillators, one external intermpt. Hitachi H813640 8-Kbyte ROM 512 Three, 8-bit timers, one 16-bit Byte RAM
PWM timer, one watchdog,
OTHER FEATURES
two SCI ports, eight 8-bit ADC, 32 KHz sub clock generator. Microchip PIC 16CR54C 768-byte ROM 25-byte Ram Twelve VO pins, 8-bit timer, high current sink/source fro direct LED drive, watchdog, timer RC oscillator. Motorola 68HC705KJl 1240-byte OTP @-byte RAM 15-stage multifunction timer, on-chip oscillator, low voltage reset, watchdog, keyboard, intempt, high current YO Zilog Z8E000 0.5-Kbyte OTP 32-byte RAM
port. One 16-bit timer, Watchdog,
four hardware interrupts, 13
vo pins.
This alarm system is created to detect an object movement in the coverage area. Alarm will trigger when object movement is detected. Nowadays, a lot of crimes happened in o w life. The idea for this alarm project came out through the total of frustration when there is no other ways to stop burglary from break-in into the house, shop or car. Of course safety was the prime concern of the security system companies. However, house owners cannot rely on neighbours or police for protecting their home or warning them if a break-in has occurred in progress. To overcome this problem, an ultrasonic security system has been developed in this project. The system has a sensor that can detect an object movement in the covered
area This project consists of 6 parts of circuit which is the power supply circuit, the
battery indicator circuit, the ultrasonic sensor circuit, the alarm circuit, the remote control circuit and the LCD display circuit. The power supply circuit produces and supply the 12V and 5V voltages. The battery indicator circuit is used to show the level of energy in the battery. The battery will act up if something happen to the power supply such as blackout. Ultrasonic sensor circuit has a transmitter circuit and the receiver circuit that operate at the same fkquency level namely 40 MIz. When there's a movement in the area covered by the circuit, the circuit's fme balance will be disturbed, thus trigger its alarm. The circuit is very sensitive and can be adjusted automatically or to stay triggered until it is reset manually after an alarm. Actually, this project use low costs budget and it is suitable for commercial used. From this project, found that the maximum distance that ultrasonic sensor can detect the object movement is 3.5 meters and for the sensitivity, it depend the environment factors such as air and noise.
ABSTRAK
Sistem Penggera ini direka untuk mengesan sebarang objek yang bergerak didalam kawasan yang diliputi oleh sistem ini. Penggera akan berbunyi sekiranya terdapat sebarang pergerakan objek yang dikesan. Pada masa kini, terdapat banyak kejadian jenayah yang berlaku di sekeliling kita Idea untuk membuat projek ini terhasil apabila sudah tiada jalan untuk menyekat perompak atau pencuri daripada
n menceroboh rumah, kereta dan juga kedai. Oleh yang demikian, projek ii
merupakan salah satu altematif untuk mengatasi masalah berikut. Sudah semestinya, aspek terpenting yang dititik beratkan dalam sistem keselamatan m e ~ p d c a n
n. keselamatan ii Tambahan pula, pemilik rumah, kereta dan kedai tidak boleh
mengharapkan jiran-jiran dan polis sahaja mefindunpi atau mengelakkan rumah, kereta dan kedai daripada diceroboh. Sebagai penyelesaian kepada masalah ini, sistem keselamatan ultrasonik direka dalam projek ini. Sistem i mempunyai n i pengesan yang mengesan pergerakan objek dalam ka yang mampu diliputi oleh sistem tersebut. Projek ini mengandungi 6 bahagian litar yang terdiri daripada litar kawalan jauh, litar bekalan kuasa, litar penunjuk paras bateri, litar pengesan ultrasonik, litar penggera dan litar untuk paparan 'LCD'. Litar bekalan kuasa berfungsi untuk menghasilkan voltan pada 12V dan 5V.Litar penunjuk paras bateri pula berfungsi untuk menunjukkan paras tenaga di dalam bateri yang digunakan. Bateri ini juga bertindak sebagai bekalan kuasa simpanan jika sesuatu terjadi kepada litar bekalan kuasa tersebut seperti terputus bekalan dan sebagainya. Litar pengesan ultrasonik mempunyai litar pemancar dan penerima yang beroperasi pada fkekuensi yang sama iaitu 40kHz. Apabiia terdapat sebamng pergerakan yang akan menyebabkan kestabilan litar terganggu, maka sistem penggera akan dihidupkan. Litar ini sangat sensitif dan boleh dilaraskan secara autornatik atau terus dipicu sehingga ia dilaraskan secara manual. Projek ini menggunakan kos yang rendah dan ia sangat sesuai untuk dipasarkan secara komersial. Selepas projek ini disiapkan dan
vii melalui analisis yang dibuat terhadap sistem penggera ini didapati bahawa pengesan ultrasonik mampu mengesan objek sehingga pada jarak 3.5 meter. Selain i N didapati juga faktor-faktorpemkitaranjuga memainkan peranan yang penting dalam mempengaruhi kesensitifan litar seperti udara dan hingar.
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND
This alarm system use an ultrasonic sensor to detect the object movement in the covered area The ultmsonic sensor was chosen because it's more compatible and appropriate for this alarm system. The features are better than i h - r e d sensor. The main factors ultmwnic sensor was chosen is, it will not infected by any type of material and color at object that has been detected. It also able to detect the small object and not infected by dust, dirt and humidity. Thus, this is also an advantage using the ultrasonic sensor. Ultrasonic sensor also has a weakness and disadvantage that is the sensor can't be installed at area that has high air flow and high noise. Actually, the ultrasonic sensor is a main component in this alarm system. Besides
that,this alarm system also combined with another circuit where this other circuit is
used as supporter to the ultrasonic sensor circuit. For ultrasonic sensor, it has 2 types of kquencies in the market namely 40 kHz and 10 MHz where for 40 kHz, it can detect up to 5 meter. Where else, for IOMHz, it capable to detect until 10 meter but the price is very expensive. As a result, for this alarm system the sensor that uses 40
kHz is more effective and appropriate.
This project has objectives that require to achieve. At the end of project, all of objectives that list are satisfied or covered. The objectives of this project are listed as below. a) To design an alarm system that capable of detecting movement object. b) Understand the operation of the circuit and applications of this alarm system. c) To know how to simulate the circuit by using the appropriate softwares. d) To improve the skills and techniques for making or designing the hardware.
1 3 PROJECT SCOPE
The scope of this project is using an ultrasonic sensor to detect the movement
ranging and detecting devices used a high-fkquency sound wave object. ~ l t r a k n i c
namely 40 kHz to detect the presence of an object.
Else, this project capable to detect object in distance about 5 meters. This is a
maximum distance that ultrasonic sensor can detect if using 40 kHz fkquency. So, in
this distance, the ultrasonic sensor can detect the movement object and trigger alarm immidiately.
1.4 PROBLEM STATEMENT.
Firstly, using the security guard is not effective and increases the cost. It cause the security guard not capable to monitor the area for 24 hours. Else, the security guard need paid the salary for every month. So, it will increase the cost for monitor the area that required.
Second, high cost required to install the security system that sophisticated. To install the security system that sophisticated, it need a high cost. So, the sophisticated security system only can install by persons that have a ability. For persons that haven't ability to install it because it need a high cost.
Third, nowadays, there have much a criminal that happen especially stealing, intrusion and something like that. The house owners usually don't know that the robbers have inside their house and not prepare to avoid them from steale.
1.5 PROJECT METHODOLOGY.
This project divided into hardware and software application.
1.5.1
Software application.
For software application, compiler software used is The PIC Basic Pro Compiler and the programmer software used is IC-Prog. For the Code Editor, it used the Microcode Studio. So, the programs can wrote and edited in Microcode Studio. It has a few steps to get the machine code (Hex) for the data to program in the microcontroller. Figure below show the process done with the software to get the .hex file.
Programming
Microcode Studio
Compiling
ICProgramming
To interface circuit
I I I
PIC Basic Pro
IC-Prog
Figure 1.1 : PIC microcontroller programming process and software that used.
1.5.2 Hardware application.
Such as software application, this part also has some steps that need to follow. Firstly, do the research and understand the concept of 'alarm system'. Information collected are regarding with PIC, 'alarm system' concept. Through this method, information that had collected previously is researched consistent with the objective of the project. Through this method, concept and principle for the project will be studied to produce the ideas for this project.
Second, the flow chart is build where this flow chart is used to show the steps that need to follow before the project is implemented. The flow chart is planned and built and this flow chart also consist ways for this project to operate and to controlling. Third, the circuit is designed. The circuit is design using a software of 'ORCAD 10.0'.
The fourth step is do the circuit simulation. The designed circuit is simulated
by using software of 'Proteus ISIS 6 Profesional' or ' E m Cicuit Maker'. By this
method, the operation of circuit can be inspect wheather the circuit has problem or not and if any, the improvement can implement.
The f f h step is build a prototype for the project. Prototype is built when the it circuit simulated is function and has no problem. It's built on the 'protoboard'. This prototype is built to test wheather the circuit has a problem or not. The improvement
can implement if the circuit designed has a problem.
The sixth step is design the 'PCB Layout'. If the circuit designed has no problem, next, the 'PCB Layout' is designed by using software of 'Protel' or 'Proteus ISIS 6 Profesional'. This method is did by full concentration to avoid a something mistake that will give difficulty when to assemble the component.
The seventh step is design the 'PCB'. The completed PCB Layout will be printed on the PCB board and drilling hole on the PCB will be done. The last step is install the component on the PCB board. Component is installed on the PCB board
i that has completed follow the circuit that has designed previously. P of component
is cut and soldered. Soldering equipment is required during this process.
Circuit Design
fail
IC Programming
Check wiring
I
Construct on PCB
Check PCB
Figure 1.2 : Flowchart of the process of designing the project.
1.6
PROJECT OVERVIEW.
Alarm System is circuits that capable to detect the moving objects as an input
and the output is alarm where alarm will trigger when detect the moving object. The ultrasonic sensor is choosing because it capable to detect the moving object up to 5 meters for 40 kHz sensor and remote control is required to wntrol this circuit. Thus, user can control the alarm system from certain distance that is about 10 meters.
Basically, this project consists of hardware and software programming, the hardware such as power supply circuit, remote control circuit, ultrasonic detector circuit, battery indicator circuit, LCD display circuit and alarm circuit.
Power Supply
t
Remote Control
Battery Indicator
1
Uk~~i~onic Detector
I
Alarm
LCD Display
Figure 1.3: Block diagram of project.
Structurally, the circuit consists of six parts: power supply circuit, battery indicator circuit, remote control circuit, ultrasonic detector circuit alarm circuit and LCD display circuit. Power supply circuit will produce 12V and 5V where it will supply the voltage to remote control circuit and ultrasonic circuit. Battery indicator circuit will show status of the battery in the power supply. Remote control circuit will control the ultrasonic detector circuit for 'ON' and 'OFF'. Alarm circuit will
trigger the alarm when sensor detects the moving object. LCD display circuit will display the output from ultrasonic detector circuit. So, input of this alarm system is from sensor and the output is alarm and LCD display. PIC is used to control the
alarm circuit and LCD display circuit. The program is in PIC Basic Pro format. This
format is used because it short and easy to build. The discussion about the program is review in next chapter.
At the last, the result from this project is the ultrasonic sensor able to detect the moving object. An alarm will trigger when moving object is detected. Else, remote control circuit able to control the ultrasonic detector circuit for 'ON' and
'OFF'.
CHAPTER 2
LITERATURE REVIEW
2.1 INTRODUCTION
This alarm system circuit has parts or elements namely the Ultrasonic Sensor,
Remote Control, PIC microcontroller and Battery. Ultrasonic sensor is the main element for this project because this sensor is used to detect any object movement around the area that is covered by this circuit. Besides that, a remote control is used to control the ultrasonic sensor circuit where it can control namely on and off the ultrasonic circuit in the distance of 10 meters. The PIC microcontroller is used to control the display of the LCD and control the alarm circuit. The types of PIC microcontroller used are 16F84A. The battery is used as back-up when something happen to the electricity. The ability to maintain the regulated supply with no electrical supply depends on the load taken from the UPS and also the Ampere how capacity of the battery.
10
2.2 ULTRASONIC SENSOR
2.2.1 An Introdnction to Ultrasonic Sensing
Ultrasonic ranging and detecting devices used a high-frequency sound wave to detect the presence of an object and its range. The systems either measure the echo reflection of the sound from objects or detect the interruption of the sound beam as the objects passed between the transmitter and receiver.
Ultrasonic sensors are commonly used for a wide variety of non contact presence, proximity, or distance measuring applications. These devices typically transmit a short burst of ultrasonic sound toward a target, which reflects the sound back to the sensor. The system then measures the time for the echo to return to the sensor and computes the distance to the target using the speed of sound in the medium.
Figure 2.1 : The 40 KHz Ultrasonic Sensor
The wide variety of sensors currently on the market differs from one another in their mounting configurations. Environmental sealing and electronics features. Acoustically, they operate at different frequencies and have different radiation pattern. It is usually not difficult to select a sensor that best meets the environmental and mechanical requirement for a particular application, or to evaluate the electronic features available with different models. Still, many users may not be aware of the acoustic subtleties that can have major effects on ultrasonic sensor operation and the measurement W i g made with them.
2.23 Selection of Ultrasonic Sensor.
Here we come to the section that can help user to select an ultrasonic sensor with the best acoustical properties, such as frequency and beam pattern, for a particular application, and how to obtain an optimum measurement fiom the sensor. The first step in this process is to gain a better understand'ig of how variations in the acoustical parameters of both the environment and the target affect the operation of the sensors. Specifically, the following variable will be discussed namely variation in the speed of sound as function of both temperature and the composition of the transmission medium, usually air, and how these variations affect sensor measurement accuracy and resolution.
Variation in the wavelength of sound as a function of both sound speed and frequency, and how this effect the resolution, accuracy, minimum target size, and the minimum and maximum target distances of an ultrasonic sensor. Variation in the attenuation of sound as a function a both frequency and humidity, and how this affects the maximum target distance for an ultrasonic sensor in air. Variation of the amplitude of background noise as a function of frequency and how it can effects the maximum target distance and minimum target size for an ultmmnic sensor. Variation in the sound radiation pattern (beam angle) of both the ultrasonic transducer and the
complete sensor system, and how this affects the maximum target distance and helps eliminate extraneous target. Variation in the amplitude of the return echo as a function of the target distance, geometry, surface and size, and how this affects the maximum target distance attainable with and ultrasonic sensor.
2.2.3 Ultrasonic Motion Detectors.
Ultrasonic motion detectors can be used to detect motion in an area where there are supposed no any moving objects. This type of motion detector is most commonly used in burglar alarm systems since they are very effective in this application.
Figure 2.2 : Ultrasonic motion detector
Figure 2.2 shows the operation of an ultrasonic motion detector. There are
mt two transducers: one e i s an ultrasonic wave and the other picks up reflections from
the different objects in the area. The reflected waves arrive at the receiver in constant phase if none of the objects in the area are moving. If something moves, the received signal is shifted in phase. A phase comparator detects the shifted phase and sends a triggering pulse to the operation motor.
2.2.4 Transducer Configurations.
A transmitting transducer sends out a pulse of sound that is detected by a
receiving transducer. Figure 1 shows several types of transducer coniigurations. Two transducers are mounted side by side. In this application, ultrasonic energy from the transmitter is reflected by an object and the echo is detected by the receiving transducer. This system measures the elapsed time from when the sound pulse is transmitted to when the echo is detected to determine the exact range of the object from the transducers. The application differs only in that a single transducer is used to transmit the sound pulse and receive the echo.
In some applications, such as high-speed counting and mechanical equipment positioning, it may be desirable to position the transducers opposing each other. For clarity, the term "sensor" will be used in this article to describe either a single or dual transducer configuration [5].
2.25 Beam Angles and Side Lobes.
Ultrasonic transducers are often designed to be directional so that the sound is efficiently transmitted or received only over a certain conical beam angle in fiont of the sensor. Ultrasonic transducers can be designed to produce any beam angle desired, from narrow (with beam widths of a just few degrees) to virtually omni directional. Some narrow beam transducer designs produce side lobes as the sound energy is transmitted. Advanced transducer designs eliminate all secondary side lobes and are more desirable for ultrasonic echo ranging.
Different applications may require different beam angles for the sensors. In most cases, however, narrower beam angles are usually preferable to broader ones. A narrow beam angle system will not detect unwanted objects that are not in the insonified path of the transducer. (To insonify means to fill a specific volume with sound from a transducer). Namw beam angle systems are also less susceptible to background ultrasonic noise, and the systems will also operate over a greater range.
The beam angle of a transducer, alpha, is defined as the total angle between the points at which the sound power has been reduced to half its peak value. These
are commonly referred to as the 3 dB down points. It is often advantageous to
compute the spot diameter that is insonifid by the ultrasonic beam.To calculate this spot diameter, use the formula: D = 2 * R * tan(O.5 * alpha) Where : D = spot diameter in inches
R = target range in inches
alpha = total beam angle in degrees
sound travels through air, its energy attenuates more rapidly if the frequency is increased. The maximum theoretical attenuation for ultrasonic sound (up to 200 kHz) may be calculated by this formula:
amax = f * 10-2
(2.4)
where:
amax =maximum attenuation in dB/fi
f = frequency in kHz
For example, using this equation, sound energy from a 215 kHz transducer would be attenuated a maximum of 2.15 dl3/ft as it traveled through air. Attenuation may be less, depending on humidity, but is not so easily defined or calculated. Although attenuation limits the range of higher frequency transducers, there is a bonus: background noise at the same higher frequency is also Iess. Higher frequency ultrasonic sensors therefore, have a much better chance of working in an acoustically noisy environment than do lower frequency sensors. Beam angle also helps to lower background noise interference by limiting the transducer's noise sensitivity to the area defined by the beam angle of the sensor. Some transducer designs utilize a detachable horn. When the horn is attached, the beam angle of the transducer is reduced. This concentration of acoustical energy into a tighter beam increases the range of the sensor and reduces the background noise as well.
2.2.7 Environmental Factors
2.2.7.1 Temperature.
The velocity of sound in air is 13,044 in./s at 0 C; it is directly proportional to air temperature. As the ambient air temperature increases, the speed of sound also increases. Therefore if a fixed target produces an echo after a certain time delay, and if the temperature drops, the measured time for the echo to return increases, even though the target has not moved. This happens because the speed of sound decreases, returning an echo more slowly than at the previous, warma temperature. If varying ambient temperatures are expected in a specific application, compensation in the system for the change in sound speed is recommended.
2.2.7.2 Air Turbulence and Convection Currents.
A particular temperature problem is posed by convection currents that contain many bands of varying temperature. If these bands pass between the sensor and the target, they will abruptly change the speed of sound while present. No type of temperature compensation (either temperature measurement or reference target) will provide complete high-resolution correction at all times under these circumstances. In some applications it may be desirable to install shielding around the sound beam to reduce or eliminate variations due to convection currents. Averaging the return times h m a number of echoes will also help reduce the random effect of convection currents. Users addressing applications requiring high accuracy and resolution should evaluate these suggestions carellly.
2.2.7.5 Acoustic Interference.
Special consideration must be given to environments that contain background noise in the ultrasonic frequency spectrum. For example, air forced through a nozzle, such as air jets used for cleaning machines, generates a whistling sound with harmonics in the ultrasonic range. When in close proximity to a sensor, whether d i t e d at the sensor or not, ultrasonic noise at or around the sensor's frequency may affect system operation. Typically, the level of background noise is lower at higher frequencies, and narrower beam angles work best in areas with a high ultrasonic background noise level. Often a baffle around the noise source will eliminate the problem. Because each application differs, testing for interference is suggested.
2.2.7.6 Radio Frequency Interference.
Another possible source of noise is RFI emitting from SCRs in a variable speed drive. Shielding around the back and sides of the transducer may prevent RFI noise from entering the system.
2.2.7.7 Splashing Liquids.
Splashing liquids should be kept from striking the surface of the sensor, both to protect the sensor from damage if it is not splash proof and to ensure an open path for the sound energy to travel. Sensors used in a splashing environment, however, should be designed to operate when wet.
Mounting orientation is also a consideration in such an environment. Straightdown orientation can cause moisture to form as a large drop on the face of the sensor, reducing the efficiency of the system. Certain applications permit mounting the sensor so that it is aimed lower than horizontal but not pointed straight down; in this orientation, gravity will help to keep moisture h m collecting on the face of the sensor.
Two methods may be used to improve the reliability of ultrasonic in the presence of splashing liquids. While beam bouncing provides a clever way of keeping the sensor out of the immediate area of splashing liquids, some applications don't lend themselves to this technique. An alternative method involves placing around the sensor a short tube that extends out past its face but not into the actual
beam pattern. It is very important that the acoustic beam not be allowed to touch the
edge of the tube; if it does, the tube might deteriorate the acoustic performance.
2.2.8 Target Considerations.
2.2.8.1 Composition.
Nearly all targets reflect ultrasonic sound and therefore produce an echo that can be detected. Some textured materials produce a weaker echo, reducing the maximum effective sensing range. The reflectivity of an object is often a function of fkquency. Lower fkquencies can have reduced reflections &om some porous targets, while higher frequencies reflect well from most target materials. Precise performance specifications can often be determined only through experimentation.
2.2.8.2 Shape.
A target of virtually any shape can be detected ulhasonically if sufficient echo returns to the sensor. Targets that are smooth, flat, and perpendicular to the sensor's beam produce stronger echoes than irregularly shaped targets. A larger target relative to sound wavelength will produce a stronger echo than a smaller target until the target is larger than approximately 10 wavelengths across. Therefore, smaller targets are better detected with higher frequency sound. In some applications a specific target shape such as a sphere, cylinder, or internal cube comer can solve alignment problems between the sensor and the target.
2.2.8.3 Target Orientation to Sensor.
To produce the strongest echoes, the sensor's beam should be pointed toward the target. If a smooth, flat target is i n c l i i off perpendicular, some of the echo is deflected away from the sensor and the strength of the echo is reduced. Targets that
are smaller than the spot diameter of the transducer beam can usually be inclined
more than larger targets. Sensors with larger beam angles will generally produce stronger echoes from flat targets that are not perpendicular to the axis of the sound
beam. Sound waves striking a target with a coarse, irregular surface will diffise and
reflect in many d i i o n s . Some of the reflected energy may return to the sensor as a
weak but measurable echo. As always, target suitability must be evaluated for each
application.
2.2.8.4 Averaging.
Certain applications involve a constantly moving target, such as the surface of agitated liquid in a tank. Analog outputs, which may be averaged by a Programmable Logic Controller or computer, will track the constant movement with
un little difficulty, but set point outputs might t r on and off unnecessarily as the target
hovers around a set point distance. Hysteresis will prevent switched outputs from oscillating to a certain extent, but if the agitation or movement is great enough, the outputs will still switch on and off.
This problem can be easily solved in a number of ways. One method is to delay the decision process by using a time delay relay (TDR). A DC powered ondelay TDR may be directly connected to a set point output and programmed to delay switching on its output u t l it has received power for a specific length of time. The ni target will then have to be past the set point distance for that programmed time before the TDR will turn on, activating the primary load. Measurement can also be averaged with a Programmable Logic Controller (PLC) or an averaging digital panel meters. PLCs have done for industrial control what word processing has done for the modem office--they have provided flexibility and have reduced costs by greatly simplifying the wiring and troubleshooting of a complete process system.
Ultrasonic systems have also increased the flexibility of measurement and control systems used in typical applications. One ultrasonic system can often replace multiple photoelectric, capacitive, or mechanical l i t switches and at the same time provide additional distance information. The fact that all measurements are made without physical contact with the target improves the lives of both the target and the sensing system.
2.3 PIC MICROCONTROLLER
23.1 What is a Microcontroller?
A computer revolution in the last 15 years has produced computer with very
high speeds and computing power while keeping their sizes compact. This revolution has occurred as a result of a development of Large-scale Integration (LSI) and Very Large-scale integration (VLSI) technologies, which put tern s of thousands of transistor on a single chip. This has made in possible to fabricate the heart of a microcomputer as a single chip called a microprocessor (h4F'U). This chip, with additional auxiliary chips called peripherals, constitutes 'a microcomputer'. Such peripherals are VO ports, memories, timers and so on.
The new technology has also made it possible to integrate this microprocessor and its peripherals in a single chip called a microcontroller (MCU) That is the reason a microcontroller is called a single-chip microcomputer.
23.2 Why Use a Microcontroller?
Microcontroller is inexpensive. The microcontroller's ability to store and run unique programs makes it extremely versatile. For example, we can program a microcontroller to make decision (pelform functions) based on predetermined situations (VO line logic) and selections. The microcontroller's ability to perform math and logic functions allows it to mimic sophisticated logic and electronic circuit. Other program can make the microcontroller behave l i e a neural circuit andfor a
fuzzy logic controller. Microcontroller is responsible for the "intelligence" in most
smart devices on the consumer market.
The are literally hundreds of microcontrollers on the market. Listed here are some of the popular 8-bit microcontroller and their features 121. These devices are the lowest cost representative devices fiom respective manufactures.
Table 2.1: Some 8-bit microcontroller s and their features. COMPANY Atmel DEVICE Attiny I1 ON-CHIP MEMORY 1-Kbyte flash 8-bit timer, analog comparator, watchdog, onchip oscillators, one external intermpt. Hitachi H813640 8-Kbyte ROM 512 Three, 8-bit timers, one 16-bit Byte RAM
PWM timer, one watchdog,
OTHER FEATURES
two SCI ports, eight 8-bit ADC, 32 KHz sub clock generator. Microchip PIC 16CR54C 768-byte ROM 25-byte Ram Twelve VO pins, 8-bit timer, high current sink/source fro direct LED drive, watchdog, timer RC oscillator. Motorola 68HC705KJl 1240-byte OTP @-byte RAM 15-stage multifunction timer, on-chip oscillator, low voltage reset, watchdog, keyboard, intempt, high current YO Zilog Z8E000 0.5-Kbyte OTP 32-byte RAM
port. One 16-bit timer, Watchdog,
four hardware interrupts, 13
vo pins.
