COMPONENTS REQUIRED :

Hardware Requirements:

• 8051 Microcontroller (AT89C51) To perform the objective

• 16 × 2 STN LCD Display To display that load is on or off

• 10KΩ Potentiometer To adjust the brightness of LCD

• Bluetooth Module (HC – 05) To receive ASCII value

• 2 – 5V Relay Module To run loads on A.C. supply

• Loads Like Light Bulb, Fan, etc

• Power Supply 5v, 9v, 12v D.C

• Voltage regulator IC 7805 To get constant 5v output

• 10µF Electrolytic Capacitor

• 2 x 33pF Ceramic Disc Capacitors

• 11.0592 MHz Quartz Crystal

• Push Button For reset

• 1KΩ x 8 Resistor Pack To pull up port 0

• Connecting wire

Software Requirements:

• Keil µVision IDE For writing code

• Proteus For Circuit Diagram and Simulation

• BlueTooth Serial Controller APK (Playstore) To send ASCII value

Circuit :

FLOWCHART:

PROGRAM:

ORG 00H

RS EQU P2.5 ; assign pin p2.5 as RS of display

RW EQU P2.6 ; assign pin p2.6 as RW of display

E EQU P2.7 ; assign pin p2.5 as E of display

MOV TMOD,#20h ; timer 1 mode 2

MOV SCON,#50h ; mode 1 (9 bit UART with variable baud rate)

MOV TH1,#0FDH ;set baud rate as 9600

SETB TR1

Clr P2.3 ; clear pin p2.3 as (used as output 1)

Clr P2.4 ; clear pin p2.4 as output 2(used as output 2)

clr E ;LCD INITIALIZATION

again:

CLR RI ;clear Recieve pin

HERE4:

JNB RI, HERE4 ;check if RI pin is 1 or 0(if 0 then again check RI pin else goto next instruction)

MOV A,sbuf ;move contents of sbuf to accumulator

CJNE A,#'A' , checknext ; check if the recieved Ascii value is equal to Ascii value of A

SETB P2.3 ;turn led1 on

ACALL display ; to display 'light on'

sjmp again ; goto label again to recieve another Ascii value

checknext:

CJNE A,#'a' , checknext1 ;check if the recieved Ascii value is equal to Ascii value of a

CLR P2.3 ;turn led1 of

ACALL displayoff ; to display 'Light of

SJMP again ; goto label again to recieve another Ascii value

checknext1:

CJNE A,#'B' , checknext2 ;check if the recieved Ascii value is equal to Ascii value of B

SETB P2.4 ;turn led2 on

ACALL display1 ; to display 'Fan on'

SJMP again

checknext2:

CJNE A,#'b' , again

clr P2.4 ;turn led2 of

ACALL displayoff1 ; to display 'Fan on'

SJMP again

display:

MOV P0, #38H ;2 lines and 5x7 matrix

ACALL send_command

MOV P0, #0EH ;display on ,cursor blink

ACALL send_command

MOV P0, #80H ; FORCE CURSOR TO 1ST LINE

ACALL send_command ; call send_command function

MOV P0, #'L' ;move Ascii value of L to port 0

ACALL send_data

MOV P0, #'I' ;move Ascii value of I to port 0

ACALL send_data

MOV P0, #'G' ;move Ascii value of G to port 0

ACALL send_data

MOV P0, #'H' ;move Ascii value of H to port 0

ACALL send_data

MOV P0, #'T' ;move Ascii value of T to port 0

ACALL send_data

MOV P0, #14H ;Shift cursor position to right

ACALL send_command

MOV P0, #'O' ;move Ascii value of O to port 0

ACALL send_data

MOV P0, #'N' ;move Ascii value of N to port 0

ACALL send_data

ret

displayoff:

MOV P0, #80H ; FORCE CURSOR TO 1ST LINE

ACALL send_command

MOV P0, #'L' ;move Ascii value of L to port 0

ACALL send_data

MOV P0, #'I' ;move Ascii value of I to port 0

ACALL send_data

MOV P0, #'G' ;move Ascii value of G to port 0

ACALL send_data

MOV P0, #'H' ;move Ascii value of H to port 0

ACALL send_data

MOV P0, #'T' ;move Ascii value of T to port 0

ACALL send_data

MOV P0, #14H ;Shift cursor position to right

ACALL send_command

MOV P0, #'O' ;move Ascii value of O to port 0

ACALL send_data

MOV P0, #'F' ; move Ascii value of N to port 0

ACALL send_data

ret

display1:

MOV P0, #38H ;2 lines and 5x7 matrix

ACALL send_command

MOV P0, #0EH ;display on cursor blink

ACALL send_command

MOV P0, #0C0H ;Force cursor to beginning of 2nd line

ACALL send_command

MOV P0, #'F'

ACALL send_data

MOV P0, #'A'

ACALL send_data

MOV P0, #'N'

ACALL send_data

MOV P0, #14H

ACALL send_command

MOV P0, #'O'

ACALL send_data

MOV P0, #'N'

ACALL send_data

ret

displayoff1:

MOV P0, #0c0H ; Force cursor to beginning of 2nd line

ACALL send_command

MOV P0, #'F'

ACALL send_data

MOV P0, #'A'

ACALL send_data

MOV P0, #'N'

ACALL send_data

MOV P0, #14H

ACALL send_command

MOV P0, #'O'

ACALL send_data

MOV P0, #'F'

ACALL send_data

ret

send_command :

CLR RW ;clear Read/Write pin (RW=0 Write mode,RW=1 Read mode)

CLR RS ;clears Register Select Pin (RS=0 Command mode,RS=1 Data mode)

SETB E ;set enable pin

ACALL DELAY ; call delay function

CLR E ;clear enable pin to stop recieving data

RET

send_data :

CLR RW

SETB RS

SETB E

ACALL DELAY

CLR E

RET

;to create delay

DELAY :

MOV R0, #5

Here1 :

MOV R1, #255

Here :

DJNZ R1, here

DJNZ R0, here1

ret

;end of delay

END ;end of program

Mobile App Configured with corresponding ASCII Value for turning on and off the home appliances:

Working + result :

1) When ‘light on ‘ button is pressed Ascii value of ‘A’ is send and Bluetooth receives it and decode it. The value received is stored in SBUF register. Then this value is moved to register A and is compared to Ascii value of ‘A’. If the values are same ,pin p2.3 become high an led 1 glows.(We could connect a relay which can drive a light ). After that display function will print ‘LIGHT ON’ on LCD display. Here in simulation I am using virtual terminal to send Ascii value of ‘A’ by pressing shift+a (A).

2) After that when I press ‘a’ controller compare received value with ‘A’ but it doesn’t match so it jump to label checknext which compares received value with Ascii value of ‘a’ and if it’s matches then pin p2.3 is cleared and led1 is turned off and ‘LIGHT OF’ is displayed.

3 ) After that when I press ‘B’ controller compare received value with ‘A’ but it doesn’t match so it jump to label checknext which compares received value with Ascii value of ‘a’ , but it doesn’t match so it jump to label checknext1 which compares received value with Ascii value of ‘B’ and it matches so pin p2.4 is set and led2 is turned on and ‘FAN ON’ is displayed.

4) After this when we press ‘b’ controller compare received value with ‘A’ but it doesn’t match so it jump to label checknext which compares received value with Ascii value of ‘a’ , but it doesn’t match so it jump to label checknext1 which compares received value with Ascii value of ‘B’, but again it doesn’t match so it jump to label checknext2 which compares received value with Ascii value of ‘b’ so pin p2.4 is cleared and led2 is turned of and ‘FAN OF’ is displayed.

Simulation:

Hardware Implementation :