Block Diagram:

Fig. 1: Overview of Automatic Light System for Home

Circuit Component Description

Fig. 2: Typical Image of Light Dependant Resistor

Block Diagram Explanation of each LDR working

Fig. 3: Block Diagram representing working principle of LDR with Microcontroller

Fig. 4: Block Diagram representing Microcontroller response to signals from LDR circuit

Sensor Working

As properties are already stated

Case 1

Case 2 

Like this one:

Fig. 5: Typical Image of IR Transmitter and Receiver

8051 Microcontroller Features

Fig. 6: Block Diagram of 8051 Microcontroller

Fnd: There are two types in it:

Final Image with all the Circuit Components

Fig. 7: Image showing circuit for detecting entrance or exit of a visitor in action

Detection of Whether Person is Entering the Room or Person is Leaving the Room

Case 1:

When person  enters  the room- as the  person enters  the room  first  sensor1  is  interrupted  and  then  the  sensor 2

The  decoding  of these  two  signals  take  place  as follows:  if   a  first  low  is  sensed  due  to sensor-1  then, the  second low  sensed  by   microcontroller due to  sensor-2    will  indicate   that  person  is coming  inside  the  room  and  hence counter  will  increment  by  one  and  the  bulb  will be switched  on.

Case 2:

When  person  exits  the room –  he  will  interrupt  the  sensor2  and  then  will  interrupt  the  sensor-1.

Software and Project Overview

Software Overview

Fig. 8: Flowchart of C Code used for Visitor Detection and Automatic Switching of lights

Other Features that can be Included

Project Overview

Fig. 9: Overview of working algorithm of Automatic Light System 

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CODE:IT  IS  WRITTEN  IN ASM  LANGUAGE:
org 0000h
ljmp main
org 0100h
main:mov p0,#00h    //make p0  as o/p port     BULB  IS CONNECTED HERE
mov p3,#0ffh       //make  p3  as i/p port        LDR  SENSORS ARE  CONNECTED HERE
mov p2,#00h      //make p2  as o/p port    FND  IS CONNECTED HERE
mov r0,#00h
mov p2,#0ffh
up:
lcall delay
lcall delay
lcall delay
lcall delay
lcall delay
lcall delay
f2:jb p3.0,f1          // CONTINUOUSLY  CHECK  FOR  A LOW  ON SENSOR-1  AND SENSOR-2 ALTERNATELY
lcall delay //
lcall delay                        //  DELAY  TO CAPTURE  THAT  EVENT PROPERLY
lcall delay                            //
lcall delay                         //
lcall delay                         //
k2:jb p3.2,k2        //AFTER  LOW  OCCURRED  AT  SENSOR-1  THEN  CHECK  FOR  SENSOR-2  WHETHER  THE  PERSON  IS                               REALLY   ENTERING  THE  ROOM
lcall delay
lcall delay
lcall delay
lcall delay
lcall delay
inc r0
setb p0.0
lcall delay
lcall delay
lcall delay
sjmp fnd1         //DISPLAY    THE   INCREMENTED  VALUE  ON  FND
lcall delay
lcall delay
lcall delay
lcall delay
lcall delay
lcall delay
f1:jb p3.2,f2           //CONTINUOUSLY  CHECK  FOR  A LOW  ON SENSOR-1  AND SENSOR-2 ALTERNATELY
lcall delay             //
lcall delay       //                           DELAY  TO     CAPTURE  THE  EVENT
lcall delay            //
lcall delay                     //
lcall delay               //
k1:jb p3.0,k1         //AFTER  LOW  OCCURRED  AT  SENSOR-2  THEN  CHECK  FOR  SENSOR-1  WHETHER  THE  PERSON  IS                           REALLY   EXITING  THE  ROOM.
lcall delay
lcall delay
lcall delay
lcall delay
lcall delay
dec r0
lcall delay
lcall delay
lcall delay
lcall delay
lcall delay
lcall delay
ljmp fnd2                          //DISPLAY  THE  DECREMENTED  COUNT
c2:
cjne r0,#00h,j1
clr p0.0
ljmp up
j1:ljmp up
fnd1:
cjne r0,#01h,a1
mov p2,#0f9h
ljmp up
a1:cjne r0,#02h,a2
mov p2,#0a4h 
ljmp up
a2:cjne r0,#03h,a3
mov p2,#0b0h
ljmp up
a3:cjne r0,#04h,a4
mov p2,#19h 
ljmp up
a4:cjne r0,#05h,a5
mov p2,#92h
ljmp up
a5:cjne r0,#06h,a6
mov p2,#82h 
ljmp up
a6:cjne r0,#07h,a7
mov p2,#0f8h
ljmp up
a7:cjne r0,#08h,a8
mov p2,#00h 
ljmp up
a8:cjne r0,#09h,a9
mov p2,#10h 
a9:ljmp up
 
fnd2:
cjne r0,#00h,ac1
mov p2,#0ffh
ljmp c2
ac1:cjne r0,#01h,b1
mov p2,#0f9h
ljmp c2 
b1:cjne r0,#02h,b2
mov p2,#0a4h 
ljmp c2
b2:cjne r0,#03h,b3
mov p2,#0b0h
ljmp c2
b3:cjne r0,#04h,b4
mov p2,#19h 
ljmp c2
b4:cjne r0,#05h,b5
mov p2,#92h
ljmp c2
b5:cjne r0,#06h,b6
mov p2,#82h 
ljmp c2
b6:cjne r0,#07h,b7
mov p2,#0f8h
ljmp c2
b7:cjne r0,#08h,b8
mov p2,#00h 
ljmp c2
b8:cjne r0,#09h,b9
mov p2,#10h
ljmp c2 
b9:ljmp c2
delay:mov r2,#128
up1:mov r1,#0ffh
here:djnz r1,here
djnz r2,up1
ret
end
 
 
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