ece 9 project document ation (final)
TRANSCRIPT
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I. Title of the Project
DIGITAL COUNTDOWN TIMER
II. Rationale
The digital countdown timer device somehow queues with
the global competitiveness in the field of high technology.
The primary reason of its existence is for convenience of
people to life. Basically, it is not designed and created to
encourage people to become lazy, but to help them do
multitasking and lessen efforts in dealing things especially
today where there is an increasing demand of human attention
towards many varied things caused by the improving
technological trends.
A busy person tends to forget the other things he is
doing, thus, this project is also designed to address to this
particular problem of any person: forgetting about other tasks
because of being very busy. With the aid of the countdown
timer device, one just easily sets up an appliance to turn on
or off, as desired, in a chosen span of time, therefore,
minimizing his efforts in manually turning on or off the
appliance.
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III. Introduction
Description of the Project
With the advent of technology, people nowadays think of
making their lives convenient. Everyone wants to make his
life more comfortable by just having everything to be easily
accessed. Answering to such want of the people, remote-control
has been invented for easy access on appliances or certain
electronic and electrical devices.
However, although, people have already been provided with
this tool to somehow reduce their efforts in operating
appliances, still, people want more and ask for more
convenience. The most common problem is that busy people tend
to forget on turning off their appliances because of the other
tasks they are doing. Hence, this project is designed to
respond to the need of a person for a certain device to
perform automatic power on or off of some appliances to avoid
leaving them operating and consuming electrical power, thus,
wasting energy and money too.
The invented device, Count Down Timer, is not limited to
automatic turning off of appliances but also its reverse. Its
application for instance is when a person would want to have
an appliance operating after a certain span of time. A
specific example would be when one would want his television
to turn on after five minutes expecting his favorite game show
will already air.
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Review of Related Literature
The following review of a related literature is taken
from www.quasarelectronics.com. The project is specifically a
simple photographic timer.
The simple photographic timer is the first of a series of
timer kits based on the 3148 hardware platform. This is a
simple down timer with selectable preset times. At the end of
the selected time period the output goes ‘low’ for 2 seconds.
There are six (6) preset times: 60, 90 120, 300, 600 and
900 seconds (1, 1.5, 2, 5, 10 and 15 minutes).
Refer to the “3148 4-DIGIT TIMING MODULE” documentation
for details of hardware features, circuit description and
assembly instructions.
TIMER SPECIFICATIONS
Timing ranges60, 90, 120, 300, 600, 900
secs
Timing resolution 1/10 second
Inputs Start, Stop and Reset
Output
2 second active low Open
collector NPN transistor,
100mA @ 30V
Display4-digit 7-segment with decimal
point, 14mm RED LED
Supply voltage 9 to 12V DC
Supply current30 to 50mA, depending on the
number displayed.
Physical size 51mm x 66mm (2.0” x 2.6”)
Connection10-way right-angle SIL header
pins, 0.1” spacing
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OPERATING INSTRUCTIONS
The ‘power up’ default time is 60 seconds (the display
shows 60.0). Pressing the STOP button cycles through the other
preset time delays.
Pressing the START button starts the timer. The display
starts running down towards zero in tenths of a second. When
it reaches zero (0.0) the open collector output pulses low for
2 seconds and the timer then resets itself to the selected
time delay.
During the count down time, pressing the START button
again has no effect. Pressing and holding the STOP button
‘freezes’ the timer at its current value. Releasing the STOP
button then resets the timer to the previously selected time
delay, ready to start again.
At any time the timer can be reset via its RESET input.
The timer will reset to the previously selected time, ready to
start again.
Applications
This timer was developed after an inquiry from a hobbyist
who wanted a simple 60 second timer when printing photographs.
At the end of 60 seconds a beeper or buzzer would sound to
indicate ‘times up’.
After some discussion about other photographic uses it
was decided to add some extra ranges as well. We also decided
on an open collector style output rather than an on-board
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buzzer. This enabled the kit to drive other devices such as
relays, making it more useful in other applications.
Open Collector Output. For more information about what an open
collector output is read the FAQ sheet at
www.quasarelectronics.com/ds.htm#3148.
Connecting to the Timer
A 10-way header strip provides external connection to the
timer, including power. All the inputs and the output are
organized as ‘pairs’ of pins, with each input or output having
a corresponding ground pin, as per the following diagram.
The ‘+’ sign indicates the actual input or output pin and
the ‘-’ sign indicates its associated ground pin.
Note: When using the output to switch a load (relay,
buzzer, etc) connect the load between the output pin and a
positive DC voltage. For example, if switching a 12V relay
connect the relay between the output pin and +12V.
Other Timing Modules
There are other firmware IC’s available for 3148:
1. 3148T2. Stopwatch with Pause function
2. 3148T3. 40KHz Auto Ranging Frequency Meter
3. 3148T0. Programmable Down Timer counting down in seconds
from a maximum of 10,000 sec
4. 3148T4 Programmable Down Timer counting down in minutes
from a max of 10,000 minutes
5. 3148T5 Programmable Down Timer counting down in hours
from a maximum of 10,000 hours
IV. Technical Aspect
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A. Detailed Explanation of How the Project Works /
Operates
Digital countdown timer is based on a micro controller,
thus securing reliability and excellent operation under any
circumstances. It can be programmed to countdown up to 999
minutes and 59 seconds. When the timer starts counting, a
relay is activated. When this time reaches zero, the relay is
disabled. This can be used for automation and wherever a
reliable timer is needed. The heart of the circuit is a micro
controller from the 8050 family manufactured by Winbond
Microchip, the W78E51B. The time is displayed by 3 seven-
segment displays and it can take any value from 0 to 999
minutes and 59 seconds.
Crystal Y1 along with capacitors C1 and C2 form the
circuit that produces the 12 MHz reference signal. As you can
easily calculate, the 12 MHz frequency leads to a duty cycle
of 1μsec. This means that every command is executed in only
1μsec. The LM7805CV voltage regulator, the D1,D2,D3 and D4
diode and the C1, are supplying the necessary +5 Volts to the
micro controller, independent of the input voltage that can
vary from 9 to 15 Volts DC. The capacitor C2 makes the
regulator capable of responding to fast changes of the load
current, making sure that the circuit will be fed with the
proper voltage at any time. Transistor Q1, resistor R1 and
diode D5 drive the relay. Transistor Q1 acts like a switch.
Diode D5 protects the transistor from the inductive voltage
that occurs at the relay terminals every time it’s activated.
Resistor R1 limits the base current and is responsible for the
switching operation of the transistor.
Visualization of the microcontroller’s output is done
through three 7-segments displays. Transistors Q3, Q4, Q5, and
resistors R6 to R13 form the network that is driving the
displays. These three transistors act as switches driven by
the voltage (0 or 5V) that appears at the microcontroller’s
pins 1 to 8 that are programmed to operate as outputs. Every
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time that a transistor is “on” the relevant display is active
and displays the contents of its seven segments (A, B, C, D,
E, and F and decimal point). The displays get the data from
the IC and display it in decimal mode e.g. numbers from 0 to
9. In order to reduce the communication lines from the IC to
the displays from 32 to 12, we have to make sure that when a
display is active, the rest two must be set off. This time-
sharing is an easy job for a device like the W78E5iB. One
should expect the brightness of the LEDs to be low using this
method of operation, but using the Q3 to Q5 transistors and
calculating the value of the R6 to R13 resistors carefully, we
achieve the highest brightness possible.
Electrical Specification
Supply Voltage:220 Volts AC +/- 10%, 60 Hertz,
single phase
Surge Protection: MOV 220V
Compatible Load Types:
Standard appliances up to 15 Amps
and incandescent lights up to 800
watts
Power Plug: 2-pin
Controlled Outlet: 2-pin
Minimum Load: No minimum load required
Maximum Load:
15 Amps (for resistive loads);
800 Watts (for incandescent
loads)
Device power
requirement:9-VDC to 15-VDC 500mA
PUSHBUTTON OPERATION
Programming controls: 2 pushbuttons: Start/Select, Reset
S2 Reset
Reset to zero
Start programming
S1 Select/Start (control)
Set minutes and seconds
Set seconds and tenths up to 999 minute.
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B. Parts List
PARTS / COMPONENT DESCRIPTION
IC = W78E51B
W78E51B is an 8- bit microcontroller which
can accommodate a wider frequency range
with low power consumption. It contains 4k
bytes flash EPROM, 128 bytes RAM, & TWO
16-bit timer/counter.
IC = NEC 2561 High Density Mounting Type Photocoupler
Q1, Q2 = C1815
Transistors are tiny electrical devices
that they can amplify an electrical signal
and they can switch on and off, letting
current through or blocking it as
necessary.
NPN 0.4 W 60V 0.15A (TO-92) ECB
Q3, Q4, Q5 = A1015 PNP 400mW 50V 150mA 80MHZ (TO-92) ECB
Q6 = LM7805CTPositive Voltage Regulator 1.5A, 5V (TO-
220)
R1=22k, R2=2.2k,
R3 to R5 =1.5k, R6
to R13=130 ohm,
R14 to R23=2.2k,
R24 to R25=2.2k,
R26=470ohm,
R27=10k, R28=4.7k,
R29=680ohm
An electronic device use for resisting an
energy or electron flow
D1, D2, D3, D4, D5
1N4001
1A 50V (DO-41 plastic)
Diode Rectifier. An electronic device with
two wires or terminals. A rectifier allows
electrical current to flow through in only
one direction and is used for converting
alternating current into direct current.
C1 to C2 =
1000uF/16V,
C3 = 4.7uF/50V
Electrolytic capacitor is a device that
stores electrical charge, using a
positively charged surface and a
negatively charged surface with a gap
between them.
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C4 to C5 = 30
pF,
C6 = 104pF
Ceramic capacitor is a filter capacitor or
condenser, the function is to filter or
smooth the rectified DC voltage produced by
the rectifier.
XTAL = 12 MHZ
The crystal is usually quartz, also has a
resonant frequency of its own, but optimum
performance is obtained when it is coupled
with an external capacitance.
YT5631BS
seven segment
LED display
0.8-inch Triple Digit, Seven Segment Display
LED = Red,
Green
Light Emitting Diode (Hi-Bright Diffused 5mm
20mA)
K1 (SPST Reed
Relay 12 Volt
DC Coil 5A
Mini PCB type)
Is an electromagnetic relay that is basically
electrically-control switch, it consists of a
coil that is energized to magnetize a
permeable iron circuit and actuate an
armature.
Miscellaneous / Other Parts:
Buzzer 12v
Push Button Switch
Toggle Switch
Illuminated Power Rocker Switch / Light
Plastic Case
Transformer – Input 220 volt / Output 12volt 500mA
(Step-down Transformer)
AC Socket Chassis-mounted
AC Cord with Plug
HC872 Plastic Case
PCB / Bolts
Fuse / Holder (quick active glass tube fuse)
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C. Block Diagram
3 SEVEN-SEGMENTLED DISPLAY
PORT LATCH &SEVEN-SEGMENT
DRIVERS
CONTROL& INSTRUCTION
REGISTER
OSCILLATOR8-BIT
MICROCONTROLLERSYSTEM
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D. Schematic Diagram
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Detailed Schematic Diagram
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E. PCB Layout
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F. Applicability of the Project
This project can be regarded as having a definite
practicality since this device is very useful to the lifestyle
of people nowadays. As to humanity, this project is even
considered feasible since we are presently living in a world
of comfort through different electronic and computer gadgets,
thus, keeping us inattentive to other chores. Since this
device is digital in nature, it is also expected that the
timing is accurate compared to a mechanically-driven timer.
Hence, this project is applicable to the kind of living we
have now and the kind of technology we have nowadays.
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V. Conclusion / Recommendation
Given the project above, encountering all the trials
during its construction, we have finally concluded that:
1. a timer is generally different from a stopwatch
because the later counts upward from zero for
measuring elapsed time while the former counts down
from a specified time interval,
2. a digital timer is more advantageous than a
mechanical timer since digital timers can achieve
higher precision because they are quartz clocks with
special electronics,
3. integrated circuits have made digital logic so
inexpensive that an electronic digital timer is now
less expensive than many mechanical and
electromechanical timers; individual timers are
implemented as a simple single-chip computer system,
similar to a watch; watch technology is used in
these devices, and
4. this project really helps busy people to (a)
integrate automation in his lifestyle so as to
decrease stress in exerting more efforts, (b) do
multitasking to save and maximize time, and (c)
conduct accurate timings in switching on or off or
in the operation of certain electrical devices.
With the above-stated conclusions, we, therefore,
recommend that:
1. this project should be advertised to public for the
aim of attracting electronic devices manufacturers
to venture on producing the product, and
2. this device should be improved to ensure safety and
maximum use and benefit of the product to the
consumers or buyers.
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VI. Appendices
A. Data Sheets / Pin Configuration
(Also See Attached for other Pin Configurations)
A F B
CA1 CA2 CA3
E D C G
DP
NC
7 – SEGMENT PIN CONFIGURATIONCOMMON ANODE
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B. Picture of the Project
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C. Curriculum Vitae
C U R R I C U L U M V I T A E
JERRY
JALA
LEPORNIO
Age : 25
Address : P-5 Bilay, Butuan City
Contact Number : 09197924325
Citizenship : Filipino
Religious Aff. : Roman Catholic
Birth Date : December 31, 1982
Birth Place : Bilay, Butuan City
Father : Teodulo Lepornio
Mother : Arcadia Cabrera Jala
EDUCATION
College : Saint Joseph Institute of Technology
Butuan City
Degree : BS in Electronics Engineering (BSECE)
4th Year
Secondary : Bilay National High School
Bilay, Butuan City
1998-99
Elementary : Bilay Elementary School
Bilay, Butuan City
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1994-95
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C U R R I C U L U M V I T A E
JOE RANDY
BALANSAG
TABUNGAO
Age : 20
Address : Alubihid, Buenavista Agusan del Norte
Contact Number : 09096656622
Citizenship : Filipino
Religious Aff. : Philippine Catholic (PECC)
Birth Date : September 13, 1988
Birth Place : Buenavista Agusan del Norte
Father : Jose Jagna Tabungao
Mother : Judith Hidalgo Balansag
EDUCATION
College : Saint Joseph Institute of Technology
Butuan City
Degree : BS in Electronics Engineering (BSECE)
4th Year
Secondary : Buenavista National High School
Matabao, Buenavista Agusan del Norte
SY 2004-05, 1st Honorable Mention
Elementary : Saint Joseph Institute of Technology
Butuan City
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SY 2000-01, 3rd Honors
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C U R R I C U L U M V I T A E
KEITH MARVIN
ATEGA
DELGADO
Age : 20
Address : Cabadbaran City
Contact Number : 09109251746
Citizenship : Filipino
Religious Aff. : UCCP
Birth Date : May 19, 1988
Birth Place : Oroquita City
Father : Wills Pagasian Delgado
Mother : Prosperity Mae Badajos Atega
EDUCATION
College : Saint Joseph Institute of Technology
Butuan City
Degree : BS in Electronics Engineering (BSECE)
4th Year
Secondary : Mindanao Institute
Cabadbaran City
SY 2004-05
Elementary : Sapang Dalaga Elementary School
Sapang Dalaga, Misamis Occidental
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SY 2000-01
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C U R R I C U L U M V I T A E
VICTOR
LABADOR
GENZON
Age : 21
Address : Guinabsan, Buenavista Agusan del Norte
Contact Number :
Citizenship : Filipino
Religious Aff. : Roman Catholic
Birth Date : Godofredo Genzon
Birth Place : Guinabsan, Buenavista Agusan del Norte
Father : Godofredo Genzon
Mother : Concordia Labador
EDUCATION
College : Saint Joseph Institute of Technology
Butuan City
Degree : BS in Computer Engineering (BSCpE)
4th Year
Secondary : Guinabsan National High School
Guinabsan, Buenavista Agusan del Norte
SY 2004-05
Elementary : Lumboyan Elementary School
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Guinabsan, Buenavista Agusan del Norte
SY 2000-01
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C U R R I C U L U M V I T A E
CYRUS
YAO
CABALLES
Age : 19
Address : P-2, B-3 San Francisco Agusan del Sur
Contact Number : 09104980638
Citizenship : Filipino
Religious Aff. : Roman Catholic
Birth Date : January 8, 1989
Birth Place : San Francisco Agusan del Sur
Father : Cesar Concerman Caballes Sr.
Mother : Virgilia Mabulay Yao
EDUCATION
College : Saint Joseph Institute of Technology
Butuan City
Degree : BS in Computer Engineering (BSCpE)
4th Year
Secondary : San Francisco West Central Elem. School
San Francisco Agusan del Sur
SY 2004-05
Elementary : Agusan Sur National High School
San Francisco Agusan del Sur
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SY 2000-01
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C U R R I C U L U M V I T A E
ALVIN REY
BOYLES
ALEMANIA
Age : 19
Address : Km. 2 Baan Highway, Butuan City
Contact Number :
Citizenship : Filipino
Religious Aff. : Roman Catholic
Birth Date : December 29, 1988
Birth Place : Baan Highway, Butuan City
Father : Sofronio Morales Alemania
Mother : Ma. Felema Luison Boyles
EDUCATION
College : Saint Joseph Institute of Technology
Butuan City
Degree : BS in Electronics Engineering (BSECE)
4th Year
Secondary : Agusan National High School
Butuan City
SY 2004-05
Elementary : Riverside Central Elementary School
Baan, Butuan City
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SY 2000-01
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VII. Bibliography
www.keil.com/dd/dcs/datashts/nuvoton/w783057c.pdf
www.kitsrus.com/pdf/k148t4.pdf
www.cannonsports.com/Images_Internet/Internet_pdfs/
TIMERS_VOL22_LOW.pdf
www.hobbyprojects.com/c/counters_and_timer_circuits.html
www.educypedia.be/electronics./circuitsbysubject.htm
www.electronickits.com/kit/comple/timers/canuk247.htm
www.circuit-innovations.co.uk/timer.html
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Saint Joseph Institute of Technology
Butuan City
DOCUMENTATION OF DIGITAL
COUNTDOWN TIMER PROJECT IN ECE 9
Submitted to:
ENGR. CATHERINE M. VERALLO
Instructor
Submitted by:
LEPORNIO, JERRY J.
TABUNGAO, JOE RANDY B.
DELGADO, KEITH MARVIN A.
GENZON, VICTOR L.
CABALLES, CYRUS Y.
ALEMANIA, ALVIN REY B.
OCTOBER 2008