LIBRARY BOOK

LOCATOR

We all might have experienced some difficulty in locating a specific book in a library. This project aims to develop a system used to locate a particular book in a library with the help of a PC.

ORG 0000H MOV TMOD,#20H ; Timer 1 in mode 2 “8 bit auto reload” MOV TH1,#-3 ; Set baud rate as 9600 MOV SCON,#50H ; Mode 1, Receive Enable=1 SETB TR1 ; Start timer 1

HERE:JNB RI,HERE ; Waiting for data to reach SBUF register MOV A,SBUF ; Moving the data received to the acc MOV P1,A ; Moving the data to Port 1 CLR RI ; Receive Interrupt Flag = 0 SJMP HERE ; Infinite loop END

• RS232 is not compatible to TTL. For this reason, to connect any RS232 to a microcontroller system, we must use “Voltage Converters” such as MAX232 to convert the

TTL logic levels to the RS232 voltage levels, and vice versa.

• MAX232 IC chips is referred to as “Line Driver”.

The parallel data obtained from the Microcontroller AT 89C51 Ports is transferred to the encoder IC HT12E

The HT12E encoder converts this parallel data into serial data which is then transmitted via the ASK transmitter.

ASK Receiver module receives the data transmitted by the ASK Transmitter and transfers this serial data to the HT12D decoder IC.

HT12D decoder IC converts the serial data into 4 bit parallel data.

This 4 bit parallel data is further fed into a 4:16 decoder IC CD 4514 to get 16 parallel outputs.

Private Declare Sub Sleep Lib "kernel32" (ByVal dw Milliseconds

As Long)

' Form load code Private Sub FormLoad() MSComm1.Settings = "9600,N,8,1" „ Operation at 9600 baud MSComm1.CommPort = 1 ‟ Change to the available comm port on your PC MSComm1.PortOpen = True „ Opens communication port End Sub

' Used for the "pause" Public Sub Pause(milli As Long) Sleep (milli) End Sub

' Button 1 code. Sends synch byte of 170, a receiver address of "0", then turns OFF all outputs on receiver.

Private Sub Command1_Click() For I = 1 To 4 ' Loop 4 times MSComm1.Output = Chr$(170) & Chr$(0) & Chr$(0) Pause 250 ' Pause 250mS Next I End Sub

. . . ' Button 16 code. Sends synch byte of 170, a receiver address of "0", then turns ON output

all outputs on receiver.

Private Sub Command16_Click() For I = 1 To 4 ' Loop 4 times MSComm1.Output = Chr$(170) & Chr$(0) & Chr$(15) Pause 250 ' Pause 250mS Next I End Sub

Private Sub Command17_Click()

If MSComm2.PortOpen = True Then MSComm2.PortOpen = False

End If

End

End Sub