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

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.

CONTENTSFunctional Block DiagramFunctional DescriptionCircuit DiagramHardwarePower SupplyL C DMATRIX keypadSerial EEPROMASK Tx and RxRelay Driver Circuit Using ULN 2003SoftwareFlow ChartAdvantagesDisadvantagesFuture Enhancements

FUNCTIONAL BLOCK DIAGRAM

TRANSMITTER SECTION

FUNCTIONAL BLOCK DIAGRAMCONTD

RECEIVER SECTION

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.

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.

CIRCUIT DIAGRAM

CIRCUIT DIAGRAM CONTD

HARDWARE DESCRIPTION

POWER SUPPLY

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.

LCD INTERFACE

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.

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.

KEY BOARD INTERFACE

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).

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.

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

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.

RELAYS AND DRIVER CIRCUIT

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.

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.

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

MICROCONTROLLER (AT89C2051)

MICROCONTROLLER (AT89C2051)

SOFTWARE

FLOWCHART

Transmitter section

Receiver section

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.

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.

RESULTBoth the devices are successfully searched.

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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