International Conference on Information and Communication Technology and Its Applications
(ICTA 2016)
Federal University of Technology, Minna, Nigeria
November 28 – 30, 2016
Development and Implementation of Microcontroller-based Improved Digital
Timer and Alarm System
Lukman Adewale Ajao1, Mutiu Adesina Adegboye2, Eustace M. Dogo1, Salihu O. Aliyu3, and Danlami Maliki1
1
Department of Computer Engineering, Federal University of Technology, Minna, Niger State
2
Department of Electrical Engineering, Federal University, Oye-Ekiti
3
Department of Telecommunication Engineering, Federal University of Technology, Minna, Niger State
Abstract—Time plays an important role in our daily activities, clocks. All clocks measures time but different clocks have
more particularly in sectional events or conference arena varying added functions or importance in their architecture.
where there is need for accurate time management. This paper This experimental timer and alarm system design in this
focuses on the development and implementation of an paper is aimed at time control in regular symposium, in order
improved digital timer with audio-visual unit using to solve the usual problems of time delay or overlaps during
(PIC16F887) microcontroller chip and other electronics presentations by sugar coated mouth presenter or people with
component such as LCD, 7-segment display, LED and buzzer too many materials, since overtime is an offense to the
as an I/O device. Thus, the need for this device in our daily audience, particularly if there are parallel sessions. Well, this
activities is to monitor the time scheduled for events, updating
device brings the solution, since it contains timer with light
and alert the audience using an audio-visual approach. The
proposed system allows apt time management and avoids time
indicator unit (Green, Yellow and Red) and alarm system to
wastage during seminar presentations and the likes. It tell the presenter the actual time spent logically. Mechanical
particularly helps presenters to be time conscious, thus, and electromechanical clocks are being modified and
making them to naturally adjust such that the allotted time is replaced by microcontroller-based digital clocks, this is due
enough to cover up their presentation. The digital timer and to the reduced cost, higher reliability, less power
alarm system presented herewith is also of advantage to the consumption, portability, wide variety of changeable
physically challenged like the deaf and blind in monitoring functions by reprogramming the chip and adding new
their sectional activities and to be fully involved about the product features. In addition to these, it gives confidence to
event situation. The system was designed in different modules, the experts and student in the area of embedded systems by
and all were interfaced together with firmware chip to simplify (learn-while doing) undertaking certain simple in-house
the mechanism’s fault diagnoses and fault corrections. experiments with frequent practice on microcontroller-based
electronics circuit design and simulation and the replacement
Keywords-digital timer, signal module, conference arena, of analog devices or components to achieve better
physically challenged, firmware chip. performance operation and simple circuit [2].
I. INTRODUCTION II. RELATED WORKS
Watches or other timing devices are very important in Several significant papers have been reviewed on the
tracking our daily activities. Timing control and alert system microcontroller-based timing system, which led to this
is significant in every aspect of our lives beyond just to tell improved digital seminar timer and alarm system
what time of the day it is. The science of time began when development and implementation. The design of a
humans started analyzing the patterns of light and darkness microcontroller-based intelligent digital volume with timer
which lead to development of the calendar year and a clock was put forward by the authors in [3]. Their system design is
based on 60-seconds/minute, 60-minutes/hour and 24- a computer based timer with speaker volume controller, it
hours/day. Clock has been designed in different architecture cannot be used in the conference arena for timing and alarm
with functions to determine or solve many problems like day purposes because of its complexity and difficult to operate
and night period, to control periodic events, to ring a bell since it uses serial communication port and setup. The
every hour or minute, to open doors, run machinery and play authors in [4], designed a digital clock using microcontroller-
music. Presently, humans are controlling actions within the based system with seven-segment display to display time
environment in a programmed and predictable manner [1]. base on the program coding. The system could not display
Therefore, keeping of time is basic for all control systems. year, month or day and no alarm system. Also, it became
In every conferences chamber, public room, schools and relatively expensive due to the use of external decoder.
other convention arena nowadays, timing is a very essential Another effort was made on microcontroller-based
factor considered in the gathering for the coordination and timing system in [5]. They came up with a 24 segment
managing of the event. Due to the level of technology display for Bangla characters and numerals. Similarly,
nowadays, time is mostly measured electronically using another effort was made by the authors in [6] towards
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International Conference on Information and Communication Technology and Its Applications (ICTA 2016)
developing a 10-segment display for Bangla digits, but their performances. The input unit, this unit used combination of
segments were not uniform, also, it had some controversy in (4x4 keypad) for the timing digits input to the system for the
portraying digits such as “1”, “2”, “3”, and “7” accurately. processing. Therefore, the output units are divided into three
Furthermore, the work in [7] improved on the work of [5] parts: First, the implementation of a 16x2 (LCD) module,
and [6] by coming up with design of an 11-segment display which display timing digit pressed for the system operation
for Bangla, Arabic and English numerals. This design gives a and time received message display as shown in the figure 9.
uniform results and it complements the effort of the previous Secondly, the 7-segment display was programmed to
authors without any segment intersections. Microcontroller respond to any input time digits for the count-down timer.
based digital Bangla clock and calendar, which display Thirdly, the (LED) indicator and buzzer, this was designed
Bangla digits on the 16x2 LCD was put forward by [8]. The and arranged serially using time delay to respond to changes
author used ATmega8 microcontroller and basic language in an input timing by shown green light when input timing is
for the system coding and programming. The clock functions fresh, then changed the state when the count-down timer is
in dual mode of performance, it display digits in both left with 5 seconds to the end and activate yellow LED, and
English and Bangla language. No alarm unit incorporating finally changed the state of LED to RED light when the input
with the system for the message notifications. The electric timing elapsed. At this stage, the buzzer will be activated
heating timer based system using Atmel AT89S52 immediately and raised alarm to show the accuracy of the
microcontroller was developed by [9]. The system deals with system. With all features attached to this system and its
the designing of biomedical related equipment for pain relief performances make it an improved digital clock and alarm
based on time dependent heat therapy, which performs system over the existing one as reported in the literature
count-down operation from 0000 – 9999 minutes with four review. This will assists presenters to strictly adhere with
7-segment display showing the actual time left for the heat time specification and management in the conference arena
therapy. The system is functioning well in the area of or events. It will also help the physically challenged people
application but lack of monitoring and alarm system when to be fully involved about the present situation of the event
the time elapsed. Author in [10] discuss an approach for and to manage their daily time activities.
managing alarms and diagnosis in an automation In achieving this system, it involves modular
management system and integrated information technology implementation of the different units separately before each
milieu, using WBEM/CIM approach technologies. Since, the of the module were linked together to function as a system
integration of system management of enterprises and unit. This give advantages of operating the system easily,
industrial automation become increasingly connected. and make the fault isolation and fault detection simple. The
Therefore, it requires alarms and diagnosis governed system. system was designed to be powered through 5V universal
The shortcoming of the system does not involved timing and serial bus (USB) port; all components are connected to the
logical method of managing industries like light indicator common 5V line and grounded. The structural design of an
and others. improved digital seminar timer and alarm system is given in
In this paper, we intend to develop and implement a Fig. 1.
microcontroller based digital timer and alarm system to
enable presenters strictly adhere with time specification and
management in conference arena or events. The system LCD
consists of three major sections which will be discussed DISPLAY
KEYPAD MCU
under system design and methodology. The device contains a
(PIC16F887)
digital clock, implemented with software codes which allow
7-SEGMENT
time to be set and reset, alarm system to alert user when the DISPLAY
preset times elapse and indicating light which tell the time
conditioning logically.
POWER
III. SYSTEM DESIGN AND METHODOLOGY LED
SUPPLY
INDICATOR
The Microcontroller based improved digital timer and UNIT
alarm system was design and implemented with the use of
both hardware and software approaches for the design, ALARM
development and implementation in modular programming. (BUZZER)
In our design, the software used in the program coding was
MikroC Pro for PIC using micro C language. The circuit
development was simulated, programmed and demonstrated Figure 1. Structural design of microcontroller-based digital timer and
using Proteus Virtual System Modeling 8.0 (PVSM) and alarm system
PICKit3 debugger was employed in the process for the real
life scenario programming of the microchip. Therefore, the A. System Controller Unit
hardware implementation of the microcontroller based The PIC 16F887 Microcontroller was used as an
improved digital clock and alarm system was carried out and intelligence device, which control and coordinate all the
tested on the breadboard before finally soldering on the activities carried out by the system development. This chip
veroboard. belongs to a mid-range 8 bits architecture and 14
The hardware design comprises of different module like instructional word length of microchip, it consists of 40 pins
the system controller unit where (PIC16F887) (1-40) and 5 ports coded as Port (A-E). Port A to port D are
microcontroller was used for the system programming and 8 bits bidirectional digital input/output (I/O) ports with
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International Conference on Information and Communication Technology and Its Applications (ICTA 2016)
additional port bits as shown in the figure 3, while Port E is a to the microcontroller of the system. The four button pins
4-bit bidirectional input/output ports. Therefore, the other along the column are configure to be inputs and grounded
four pins like pin (11 and 12, 31 and 32) are for the (GND), while all the four buttons across the rows are
controller power (Vss) and ground (GND) respectively, most configure to be output as shown in the simulation circuit
of the pins of this chip are multifunctional pins and design in figure 9. The four input pins along the column are
multipurpose. Details description of some selected pins connected to the Port D (RD0-RD3) of the microcontroller
number was given in the table 1. For instance, pin 1 and grounded, while the other output four pins across the
(RE3/MCLR/VPP), pin 5 (RA3/AN3/VREF+/C1IN+), pin row of the button are connected to the Port D (RD4-RD7)
13 (RA7/OSC1/CLKIN) and pin 39 (RB6/ICSPCLK ). with 10k resistor for each connection pins. If one of the
PIC16F887 has high performance RISC CPU with sixteen buttons is pressed, it connects a pair of pins together.
features of high operating speed; it works on 4-20MHz This feature helps in detecting which button is pressed. The
oscillator/clock input and 200ns instruction cycle [11]. It also internal and external architecture of the keypad connection
contains three timer modules; Timer0, Timer1 and Timer2, was shown in the figure 4 and figure 5 respectively.
where timer0 module was used for the timing in this work.
The OPTION register is a readable and writable register
which contains various bits to configure the Timer0/WDT A
prescaler, External INT interrupt, Timer0 and Weak pull-ups
resistor on PORTB.
B
TABLE I. DETAILS OF SOME SELECTED PIN NUMBERS AND C
DESCRIPTION OF PIC16F887 MICROCONTROLLER CHIP.
Pin Pin Name Description
D
N0
1 RE3/MCLR/VPP RE3: Digital I/O Port E, Pin 3
MCLR: Low logic controller power 1 2 3 4
reset or clear screen.
VPP: Microcontroller programming
voltage Figure 3. Internal architecture of 4 x 4 matrix keypad connections
5 RA3/AN3/VREF+ RA3: Digital I/O Port A, Pin 3
/C1IN+ AN3: Analog to Digital channel 3
VREF+:Analog to Digital positive
voltage reference input
C1IN+: Positive input comparator 1
13 RA7/OSC1/CLKI RA7: Digital I/O Port A, Pin 7
N OSC1: First input crystal oscillator
CLKIN: External clock input
39 RB6/ICSPCLK RB6:Digital I/O Port B, Pin 6
ICSPCLK: Serial clock programming
Figure 4. External architecture of 4 x 4 matrix keypad connection
C. Output Unit
The first output device used in this system was 16x2
LCD (HD44780) parallel interface chipset, 16 pins
connection, easy to configure and program which commonly
used in the various simple and complex embedded systems
to exhibit output information. LCD (Liquid Crystal Display)
is an electronic module use to display alphanumeric data on
Figure 2. Pin configuration of the PIC 16F887 microcontroller chip the screen, a 16x2 LCD denotes 16 columns and 2 rows
capable of displaying 16 characters per line/row and there
B. The Input Unit (4x4 matrix keypad) are two (2) of such lines/rows. In this work, 4-bit data mode
In this work, 4x4 matrix keypad was used as a data input (D4-D7) was used instead of the 8-bit counterpart. The data
device for the system timing or logical configuration of the line pin (D4-D7) of LCD was connected to the port C, pin
system operation. In the process of connection, the four (15-18) of microcontroller respectively. In the process of
button pins along the rows are connected with the four interfacing the LCD with microcontroller, the LCD pins was
buttons pins across the column to reduce the input connected accordingly as shown in the figure 6a before
connection switches to 8 pins, which are directly connected embarking on the bread boarding and soldering.
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International Conference on Information and Communication Technology and Its Applications (ICTA 2016)
(a) (b)
Figure 5. Pin configuration and circuit implementation of 16 x 2 LCD module
D. Seven Segment Display Unit
A seven segment display is the most common basic
electronic display device capable to demonstrate digits from
0-9 and beyond in a clearly digital form. It can be used in
many applications of electronics and embedded system
devices to display numeric information like in the digital
clocks, radio, microwave ovens, electronic meters etc. The
arrangement are laid out as a squared-off shown in the in
Figure 7, every LED is assigned a name from 'a' to 'h' and is
identified by its name. Seven LEDs 'a' to 'g' are used to
display the numerals while 'h' is used to display the
dot/decimal [12]. Common cathode type of seven-segment
display was used in this design, the pin 11 and 12 of the
device was connected to the Port A, pin (2-5) of
microcontroller using NPN 2n2222 transistor to improve the Figure 7. LED connection to microcontroller
brightness of the display. Also, the pins connection of the
From Figure 7, using voltage divider rule with Vcc 9V ,
each 2-digit seven segment display (a-g) and the decimal
point (dp) was connected together and directly connected to
the port B, pin (33-40) for the digit display. where RD is the resistance of the green LED, R1 is obtained
In CC configuration, the negative terminals of all LEDs
thus:
are connected to the common pins (low voltage) and
common pin is connected to ground to glow a particular
LED when its corresponding pin is given high logic to Vcc R1
display a number. VR1
R1 RD
R1Vcc VR1 ( R1 RD )
(1)
R1 (Vcc VR1 ) VR1 RD
VR1 RD 900 100
R1 300
Vcc VR1 12 9
Figure 6. The cascaded four seven segment display and the pin
configuration of each segment F. Audio Unit
A buzzer is an audio signaling device, which may
be mechanical, electro-mechanical, or piezoelectric. The
E. Light Emitting Diode Unit wide areas of application of buzzers include: alarm devices
The application of (LED) in this development system like clock, timers and confirmation of user input such as a
was divided into two functions. First, it serves as an indicator mouse click or keystroke [14]. The buzzer is connected with
light, and also as control and monitoring timing system. NPN transistor, wired with the third LED that indicating stop
Three different color of LED was used for the control and and connected to the port E, pin 10 of microcontroller. This
monitoring system (Green, Yellow and Red) which indicate device was configured and programmed to sounds whenever
time begins, ready to stop and stop respectively. The LED the preset time interval has elapsed or when red light is
was connected to port E, pin (8-10) of microcontroller, the activated (STOP). Figure 8 depicts the wiring method of
buzzer and then grounded [13]. buzzer in our design.
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International Conference on Information and Communication Technology and Its Applications (ICTA 2016)
V. SYSTEM FLOWCHART
Start
Input
Time
No
Is time
valid?
Figure 8. Wiring method of buzzer with NPN transistor
From Figure 8, we have: Yes
Count down on green
VB I B RB VBE
LED
Ic2 103
IB 10 A
200 (2) No
VB 10V Has 90% of time
VBE 0.7V elapsed?
Therefore, RB which is the base resistor of the transistor is Yes
obtained as:
Put ON Yellow LED and
VB VBE 10 0.7 count down
RB 930 (3)
IB 10 106
No
Hence, a 1KΩ resistor value was used. Time Up?
Yes
IV. DISCUSSION
The development and implementation of microcontroller-
based digital timer and alarm system was design and tested
Put ON Red LED,
to ensure workability and reliability of its performance. The Sound Alarm
system can be programmed for timing purposes by
connecting it to the laptop through a USB port for power-
driven, and simply press the ‘*’ key on the keypad to prepare Stop
the system for data input or timing code. Then press the
ON/OFF key to enter the countdown time or event time. For
the proper interaction, the digits pressed/entered are Figure 9. Flow chart of microcontroller based digital timer and alarm
system
displayed on the LCD, when the user is done with timing
range, the ‘#’ key is pressed and the system checks the time VI. IMPLEMENTATION
inputs. If it is a valid time, the message display on the LCD
“TIME RECEIVED” or else display “INVALID TIME”. The design is an embedded microcontroller-based
This required a user to enter a valid time. system, with LCD, LED, seven segment display, keypad,
But if a valid time is entered, the time will be shown on buzzer and others electronic components. It is divided into
the “7-Segment Display”, activating the green light and the hardware and software parts. In the software part, the
time will start counting. When countdown time reaches 90% MicroC program on the controller core can initialize the
of the stipulated time, the Green LED goes off and activates parameters, configure the simulation and communicate with
yellow LED. Once the countdown time expired, the yellow the hardware model.
LED goes off and activates Red LED as well as buzzer If the time set for the system is 5 minutes in the clock,
activated to sound in support of expiring time set. green light is activated and glow indicate the beginning of
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International Conference on Information and Communication Technology and Its Applications (ICTA 2016)
time, and counter will count by decreasing timer till it gets to activate and turn ON, at the same time it triggers the alarm
1 minute to the end of timing, after which the yellow LED system; the buzzer immediately comes up and interrupts the
will come up to tell about the timing. Finally, when it counts presenter logically. Details implementation and testing of the
to exactly 5 minutes of the total timing, the red lights will be digital timer and alarm system are shown in the figure 11.
+5v
+5v +5v RV1
+5v +5v LCD1
LM016L
44%
Q4 Q2
2N2222 2N2222 Q1 10k
2N2222
Q3
VDD
VSS
VEE
RW
RS
D0
D1
D2
D3
D4
D5
D6
D7
2N2222
E
1
2
3
4
5
6
7
8
9
10
11
12
13
14
R4
2k
R5
2k
R2 R3
2k 2k
+5v
R1 R9
20k 330
D1
LED-GREEN
U1
1 15
RE3/MCLR/VPP RC0/T1OSO/T1CKI
16
RC1/T1OSI/CCP2
2 17
RA0/AN0/ULPW U/C12IN0- RC2/P1A/CCP1
3 18
RA1/AN1/C12IN1- RC3/SCK/SCL
4 23
RA2/AN2/VREF-/CVREF/C2IN+ RC4/SDI/SDA
5 24
RA3/AN3/VREF+/C1IN+ RC5/SDO
6 25
RA4/T0CKI/C1OUT RC6/TX/CK
7 26
RA5/AN4/SS/C2OUT RC7/RX/DT
14
RA6/OSC2/CLKOUT
13 19
RA7/OSC1/CLKIN RD0
20
RD1
33 21
RB0/AN12/INT RD2
34 22
RB1/AN10/C12IN3- RD3
35 27
RB2/AN8 RD4
36 28
RB3/AN9/PGM/C12IN2- RD5/P1B
37 29
RB4/AN11 RD6/P1C
38 30
RB5/AN13/T1G RD7/P1D
39
RB6/ICSPCLK
40 8
RB7/ICSPDAT RE0/AN5
9
RE1/AN6
10
RE2/AN7
PIC16F887
A 7 8 9
B 4 5 6
R6 R7 R8
330 330 330 C 1 2 3
ON
D
C 0 = +
1
2
3
4
+5v
BUZ1
R10 R11 R12 R13
BUZZER 10k 10k 10k 10k
Q5
2N2222
Figure 10. Complete simulation circuit diagram of digital timer and alarm system
Figure 11. Implementation of digital timer and alarm system on the
breadboard
Figure 13. Packaging of the digital timer and alarm system
VII. COMPARATIVE STUDY WITH SIMILAR WORK IN
LITERATURE REVIEW
The development of microcontroller based improved
digital timer and alarm system put forward in this paper was
evaluate by comparing with the existing similar work in the
Figure 12. Implementation of digital timer and alarm system on the Vero literature from the perspective of the components used,
board performances and their area of applications.
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International Conference on Information and Communication Technology and Its Applications (ICTA 2016)
TABLE II. COMPARATIVE STUDY WITH SIMILAR WORK IN THE firmware technology like System-on-Chip (SoC), complex
REVIEW LITERATURE.
programmable logic device (CPLD) or field programmable
S/N Author & Project Title Parameter of gate array (FPGA), Arduino microcontroller etc to make the
Year Comparison device efficient, portable compact, and more functions.
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