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MICROCONTROLLER BASED INSTRUMENT IDENTIFICATION AND DETECTION
Project AssociatesChebrolu Girisai Praveen 4BD04EC021Laxman
Nyamagouda 4BD04EC039Veeresh P M 4BD04EC109Vikas M 4BD04EC111
Guided By Mr. K M Prakash M. Tech, MISTE
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ABSTRACT We know that as technology is growing more and more
equipment are being developed. In laboratories there will be many
instruments and equipments kept in big rooms and out of them few
will be used frequently, some are used occasionally. Naturally
human tendency is that after the complete usage of instruments or
equipments they will not be placed in right order and correct
location. Hence it becomes difficult to locate them immediately
when they are required again. Our project intends to eliminate this
problem. The objective of the project is to develop such a system,
which can identify and indicates the location of the instruments
and equipments in laboratories.
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CONTENTSFunctional Block DiagramFunctional DescriptionCircuit
DiagramHardwarePower SupplyL C DMATRIX keypadSerial EEPROMASK Tx
and RxRelay Driver Circuit Using ULN 2003SoftwareFlow
ChartAdvantagesDisadvantagesFuture Enhancements
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FUNCTIONAL BLOCK DIAGRAM
TRANSMITTER SECTION
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FUNCTIONAL BLOCK DIAGRAMCONTD
RECEIVER SECTION
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FUNCTIONAL DESCRIPTIONHere first we have to enter the names of
the devices which are to be searched through key board by pressing
ENTER key, the entered data are stored in serial eeprom 24c32A in
which 32k bytes of information can be stored. when the system is
switched on it will be displaying searching mode then by pressing
NEXT key it shows the list of devices to be searched one by one.
Pressing OK key will confirms the device to be searched and will
transmit its particular code through ASK transmitter via
relays.
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FUNCTIONAL DESCRIPTION CONTDAll the devices which are to be
searched will be equipped with receiving module embedded in it. All
these modules will receive the signal through ASK receiver and will
be decoded there and further processed by the microcontroller to
see whether the received code is its own. If yes then device
indicates its presence by turning on the buzzer. Now the user can
identify and locate the device easily and fetch it if
necessary.
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CIRCUIT DIAGRAM
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CIRCUIT DIAGRAM CONTD
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HARDWARE DESCRIPTION
POWER SUPPLY
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POWER SUPPLY CONTDOur system and associated circuitry requires
5V of DC power supply which we have designed using step-down
transformer, bridge rectifier, capacitors and voltage
regulator.Three terminal IC 7805 meets the requirement of +5V
regulated. The secondary voltage from the main transformer is
rectified by diodes D1-D4 and are filtered by capacitor C1. This
unregulated dc voltage is supplied to input pin of regulator IC. C2
is an input bypass capacitor and C3 is to improve ripple rejection.
The IC used is fixed regulator with internal short circuit current
limiting and thermal shut down capability.
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LCD INTERFACE
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LCD INTERFACE CONTDFrequently AT89C51 program must interact with
the outside world using input and output devices that communicate
directly with a human being. One of the most common output devices
used is a LCD. Some common LCDs are 16x2 and 20x2 displays, which
mean 16 characters per 2 line and 20 characters 2 per lines,
respectively.LCD used here has 14 pins.The data pins of LCD are
connected to P2 and control pins to P1.4, P1.5 and P1.6.
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LCD INTERFACE CONTDBefore using LCD for displaying it has to be
initialised by specifying some of the commands like start of the
cursor position, clear screen etc.
Then the data to be displayed are sent through port 2 of
microcontroller by applying appropriate control signals on En, R/W
and RS pins.
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KEY BOARD INTERFACE
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KEY BOARD INTERFACE CONTDWhen a key is pressed, it shorts one
row and column; otherwise, the row and the column do not have any
connection. The interfacing of a matrix keyboard requires two
ports; one output port and the input port.Rows are connected to the
output port, and the columns are connected to the input port. They
are capable of interfacing a matrix keyboard as large as 64 keys,
eight columns and eight rows. In our project we are using 4X4
matrix keyboard of 16 keys which are connected to port 0 (p0).
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KEY BOARD INTERFACE CONTD
Initially all the column lines will be in high state and each
rows are grounded by making the row port lines low one by one. If
we are in say first row it will check whether any key is pressed by
reading the column port. If any one of the first row is pressed
then the particular column will get low level if in the first row
then the column number which gets the low signal will be the key
number. For example if we start the column number from zero then
the first key identified as number zero. If none of the key is
pressed in row 1 then controller will ground the next row in this
row if any key is pressed it will identify the column number and
adds number 4 once to get exact to get exact key number if it is in
the row 3 it add number 4 two times to the column number to get the
correct key.
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SERIAL EEPROMStandard Voltage operation-2.7VInternally organized
4096*8(32K)Bidirectional Data Transfer ProtocolWrite protect pin
for Hardware Data protectionSelf-timed write cycle(5 ms Max)High
Reliability - Endurance:1 million write cycles Data Retention:100
years
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PIN DESCRIPTIONA0, A1, A2 Chip Address Inputs: The A0, A1, A2
inputs are used by the 24x256 for multiple device operation. The
levels on these inputs are compared with the corresponding bits in
the slave address .The chip is selected if the compare is true. Up
to eight devices may be connected to the same bus by using
different chip is select bit combinations.SDA Serial Data : This is
a bi-directional pin used to transfer addresses and data into and
data out of the device. It is an open drain terminal. Therefore,
the SDA bus requires a pull up resistor to Vcc (typical 10 k ohm
for 100 kHz, 2k ohm for 400 kHz). P1.2 is connected to this pin.SCL
SERIAL CLOCK: This input is used to synchronize the data transfer
from and to the device, which is connected to P1.3.WP: This pin can
be connected to either Vss, Vcc or left floating.
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RELAYS AND DRIVER CIRCUIT
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RELAYS AND DRIVER CIRCUIT CONTDA relay is an electrically
controllable switch used widely in industrial controls, automobiles
and appliances. Relay basically consists of three components: Coil
, Spring & Contacts. When current flows through the coil
magnetic field is created around the coil which causes armature to
be attracted to the coil. The armatures contact acts like a switch
and closes or opens the circuit. There are mainly three types of
relays available namely SPST,SPDT and DPDT. Microcontroller pins
lack sufficient current to drive the relays. For this reason we use
the driver ULN2803.
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ASK TRANSMITTER AND RECEIVERIt is designed for remote control
alarm and security system, authorization/ access
control.Transmitter has 4 buttons (A,B,C,D) , and there are 4
corresponding outputs on the receiver.Depending on the switch
operation the receiver will give either a high level or a high
pulse on the corresponding output.An encoder and decoder are used
at transmitting and receiving end respectively.
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ASK TRANSMITTER AND RECEIVER CONTDThe simplest and most common
form of ASK operates as a switch, using the presence of a carrier
wave to indicate a binary one and its absence to indicate a binary
zero. This type of modulation is called on-off keying, and is used
at radio frequencies to transmit Morse code (referred to as
continuous wave operation).More sophisticated encoding schemes have
been developed which represent data in groups using additional
amplitude levels. For instance, a four-level encoding scheme can
represent two bits with each shift in amplitude; an eight-level
scheme can represent three bits; and so on. These forms of
amplitude-shift keying require a high signal-to-noise ratio for
their recovery, as by their nature much of the signal is
transmitted at reduced power
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MICROCONTROLLER (AT89C2051)
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MICROCONTROLLER (AT89C2051)
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SOFTWARE
FLOWCHART
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Transmitter section
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Receiver section
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ADVANTAGESAny kind of devices can be searched.
Similar devices with different specifications can be easily
identified.
saves manual searching time.
User friendly.
Uses less power.
Only one time investment and reliable one.
Shock resistant.
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DISADVANTAGESA little expensive.
Acquires a considerable amount of space hence receiver module
appears bigger than the device if in case it is too small.
In case of failure of transmitter whole system will not
work.
The maximum no. of characters in the device name is restricted
to 8.
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RESULTBoth the devices are successfully searched.
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FUTURE ENHANCEMENTSThe whole project can be made wireless by
introducing battery instead of direct supply which restricts the
receiver modules and transmitter modules stationary.For the sake of
practical implementation size of receiver module circuitry can be
minimised so that it acquires less space.Using the same concept the
project can be implemented in a way to achieve theft recovery by
using GPS instead of ASK Tx and Rx
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THANK YOU