NURUSHIFA BINTI SEYAD SULTAN 171151509 ENT216 SEM 12018/2019 Assignment 1 Name

NURUSHIFA BINTI SEYAD SULTAN 171151509 ENT216 SEM 12018/2019
Assignment 1
Name :Nurushifa binti Seyad Sultan
Matrix Number :171151509
Biomedical Electronic Engineering,
School ofMechatronic Engineering,
Universiti Malaysia Perlis
Perlis, Malaysia
[email protected]
I. INTRODUCTION
555 timer IC can be found in many electronic devices
that is used for various applications. 555 timer IC was
designed by Hans. RCamenzind in 1971. The 555 timer IC
has 8pins where pin 1is for ground supply, pin 2is for
trigger, pin 3is for output, pin 4is for reset, pin 5is for
control, pin 6isfor threshold, pin 7isfor discharge, and pin
8isfor positive supply. The cost for this 555 timer IC islow
and can be used easily. The duty cycle of this timer can be
adjusted. The 555 timer IC can be used in oscillators and
pulse generation.
II. CIRCUIT MECHANISM
A. Problem Statement
To design block diagram and circuit diagram that could
help us to see more of inside of the cabinet using IC 555
Timer.
B. Types of Modes
The re are 3types of modes for 555 timer IC which are
astable mode, monostable mode, and bistable mode.
Astable mode has no stable state. The output will be
between high state and low state. In this mode, the 555
timer IC makes a continuous rectangular pulses with a
specific frequency.
Monostable mode has only one stable state and one
unstable state. When the stable output was set at 1(high),
the output will also be 1 (high). When there is any
interruption, the timer output will be 0(low). When the low
state isunstable, itwill go to 1(high) automatically after the
interruption ispassed.
Bistable mode has both stable states. Inthis mode, the
555 timer ICwill act like abasic flip flop. There will be two
different trigger inputs will be used to change the state.
(High to low, and low to high)

III. PREPAR ATION OF CIRCUIT
A. Components
One of the components used isLED (Light-Emitting Diode).
LED isused to provide light in the shoe cabinet when the
cabinet isopened.
Another component that was used isresistor. The function
of resistor is to control the flow of the current to other
components.
Other component is capacitor. Capacitor is used to store
electrical energy.
Other than that, 555 IC timer isalso used. 555 IC timer is
used to trigger the Light-Emitting Diode (LED) and also to
provide atime delay. The operation mode that was used is
monostable mode.
Finally, battery was used. Battery is used to provide the
circuit with source of energy.
B. Block Diagram
NO YES
C. Flow of Project
For this shoe cabinet, 10V of battery isused as the power
supply. 50,000 Ohm of resistors and 0.02 Farad of capacitor
was used. When someone opens the door of the shoe
cabinet, the LED will turn on automatically and the light will
remain for 90 seconds. Current will flow through the circuit
and trigger sthe 555 IC timer once the cabinet ‘sdoor is
open. The LED will turn off automatically after 90 seconds
even ifthe cabinet ‘sdoor isstill open. This process happens
to save the energy. The capacitor will continue to charge
the energy once the door isclosed.
IV. CIRCUIT DESIGN
VCC OUT
U1
555_TIMER_RATED
GND
DISRST
THR
CONTRI
R150k?
LED
R250k?
R350k?
C10.02F
C20.02F
V1
10V
REFERENCES
1 A.M. Bhatt, “555 Timer IC: Introduction, Basics &Working with Different Operating Modes “retrieved from https://www.engineersgarage.com/tutorials/555-timer-ic-introduction-basics-working-different-operating-modes
2 Dejan, “555 Timer IC –Working Principle, Block Diagram, Circuit Schematics “,retrieved from https://howtomechatronics.com/how- it-works/electronics/555-timer-ic-working-principle-block-diagram-circuit-schematics/
3 Jason, (November 27,2018), “IC555 Timer Working: Pin Diagram & Specifications “,retrieved from https://electronicsforu.com/resources/learn-electronics/555-timer-working-specifications
4 Dilip Raja, (June 18,2015), “Understanding 555 Timer IC”,retrieved from https://circuitdigest.com/article/555-timer-ic
START
DOES THE SHOE CABINETDOOR IS OPENED?
THE LED TURNS ON
THE LED WILL REMAIN ON FOR 90SECONDS
THE LED WILL TURN OFF
AUTOMATICALLY
END