AUTOMATIC ROOM LIGHT CONTROLLER WITH
BIDIRECTIONAL VISITOR COUNTER
A PROJECT REPORT
Submitted by
Sarita Yadav
in partial fulfillment for the award of the degree
of
BACHELOR OF TECHNOLOGY
in
ELECTRONICS AND COMMUNICATION ENGINEERING
JAMIA MILLIA ISLAMIA NEW DELHI
1
ABSTRACT
This Project “Automatic Room Light Controller with Bidirectional Visitor
Counter” is a reliable circuit that takes over the task of controlling the room lights
as well us counting number of persons / visitors in the room very accurately. When
somebody enters into the room then the counter is incremented by one and the light
in the room will be switched ON and when any one leaves the room then the
counter is decremented by one. The light will be only switched OFF until all the
persons in the room go out. The total number of persons inside the room is also
displayed on the seven segment displays. The microcontroller does the above job.
It receives the signals from the sensors, and this signal is operated under the
control of software which is stored in ROM. Microcontroller AT89S52
continuously monitor the Infrared Receivers. When any object pass through the IR
Receiver's then the IR Rays falling on the receivers are obstructed. This obstruction
is sensed by the Microcontroller.
2
TABLE OF CONTENTS
1. INTRODUCTION
2. BLOCK DIAGRAM DESCRIPTION
2.1 Power Supply
2.2 Enter and Exit Circuits
2.3 89S52 Microcontroller
2.4 Relay Driver Circuit
3. CIRCUIT DESCRIPTION
3.1 Transmission Circuit
3.2 Receiver circuit
4. LIST OF COMPONENTS
5. DESCRIPTION OF THE COMPONENTS USED
5.1 Microcontroller AT89S52
5.2 TSOP1738 5.3 555 (TIMER IC)
5.4 LTS 542
5.5 LM7805
5.6 Relay Circuit
6. FLOW CHART
7. PROGRAM
3
8. CONCLUSION
9. BIBLIOGRAPHY
4
INTRODUCTION
Project title is “AUTOMATIC ROOM LIGHT CONTROLLER WITH
BIDIRECTIONAL VISITOR COUNTER”.
The objective of this project is to make a controller based model to count
number of persons visiting particular room and accordingly light up the room.
Here we can use sensor and can know present number of persons.
In today’s world, there is a continuous need for automatic appliances.
With the increase in standard of living, there is a sense of urgency for
developing circuits that would ease the complexity of life.
Also if at all one wants to know the number of people present in room so
as not to have congestion, this circuit proves to be helpful.
5
BLOCK DIAGRAM
7-SEGMENT DISPLAY
6
ENTER SENSOR
SIGNAL CONDITIONING
EXIT SENSOR
SIGNAL CONDITIONING A
T89S52
RELAYDRIVER
LIGHT
POWER SUPPLY
BLOCK DIAGRAM DESCRIPTION
The basic block diagram of the bidirectional visitor counter with automatic light
controller is shown in the above figure. Mainly this block diagram consists of the
following essential blocks.
1. Power Supply
2. Entry and Exit sensor circuit
3. AT89S52 micro-controller
4. Relay driver circuit
1. Power Supply:-
Here we used +12V and +5V dc power supply. The main function of this block
is to provide the required amount of voltage to essential circuits. +12V is given to
relay driver. To get the +5V dc power supply we have used here IC 7805, which
provides the +5V dc regulated power supply.
2. Enter and Exit Circuits:-
This is one of the main parts of our project. The main intention of this block is
to sense the person. For sensing the person we are using a TSOP 1738 sensor. By
using this sensor and its related circuit diagram we can count the number of
persons.
7
3. 89S52 Microcontroller:-
It is a low-power, high performance CMOS 8-bit microcontroller with 8KB of
Flash Programmable and Erasable Read Only Memory (PEROM). The device is
manufactured using Atmel’s high-density nonvolatile memory technology and is
compatible with the MCS-51TM instruction set and pin out. The on-chip Flash
allows the program memory to be reprogrammed in-system or by a conventional
nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash
on a monolithic chip, the Atmel AT89S52 is a powerful Microcontroller, which
provides a highly flexible and cost effective solution for many embedded control
applications.
4. Relay Driver Circuit:-
This block has the potential to drive the various controlled devices. In this block
mainly we are using the transistor and the relays. One relay driver circuit we are
using to control the light. Output signal from AT89S52 is given to the base of the
transistor, which energizes the particular relay, because of this, appropriate device
is selected and which performs its allotted function.
8
CIRCUIT DESCRIPTION
There are two main parts of the circuits.
1. Transmission Circuit (Infrared LEDs)
2. Receiver Circuit (Sensors)
9
1. Transmission Circuit:
10
This circuit diagram shows how a 555 timer IC is configured to function as
basic astable multivibrator. The astable multivibrator generates a square
wave, the period of which is determined by the circuit external to IC 555. The
astable multivibrator does not require any external trigger to change the state
of the output. Hence called free running oscillator. The time during which
the output is either high or low is determined by the two resistors and
a capacitor which are externally connected to the 555 timer.
IR Transmission circuit is used to generate the modulated 36 kHz IR signal.
The IC555 in the transmitter side is to generate 36 kHz square wave. Adjust the
preset in the transmitter to get a 38 kHz signal at the o/p. Then you point it over the
sensor and its o/p will go low when it senses the IR signal of 38 kHz.
11
2. Receiver Circuit:
Fig. Receiver circuit
The IR transmitter will emit modulated 38 kHz IR signal and at the receiver
we use TSOP1738 (Infrared Sensor). The output goes high when there is an
interruption and it return back to low after the time period determined by the
capacitor and resistor in the circuit i.e. around 1 second. CL100 is to trigger the
IC555 which is configured as monostable multivibrator. Input is given to the Port 1
of the microcontroller. Port 0 is used for the 7-Segment display purpose. Port 2 is
used for the Relay Turn On and Turn off Purpose.LTS 542 (Common Anode) is
used for 7-Segment display and that time Relay will get voltage and triggered, so
light will get voltage and it will turn on and when counter will be 00 and at that
time Relay will be turned off. Reset button will reset the microcontroller.
12
Hardware Design
Fig. 4.1 Snap of the entire circuit
13
MicrocontrollerAT89C52
Infrared SensorTSOP1738
7-SegmentDisplay
Relay
Timer IC555
LIST OF COMPONENTS
Microcontroller – AT89S52
IC – 7805
Sensor – TSOP 1738 (Infrared Sensor)
Transformer – 12-0-12, 500 mA
Preset – 4.7K
Disc capacitor – 104,33pF
Reset button switch
Rectifier diode – IN4148
Transistor – BC 547, 2N2222
7-Segment Display
14
DESCRIPTION OF THE COMPONENTS USED
1. Microcontroller AT89S52:
The AT89S52 is a low-power, high-performance CMOS 8-bit
microcontroller with 8K bytes of in-system programmable Flash memory. The
device is manufactured using Atmel’s high-density nonvolatile memory
technology and is compatible with the Industry-standard 80C51 instruction set and
pin out. The on-chip Flash allows the program memory to be reprogrammed in-
system or by a conventional nonvolatile memory pro-grammar. By combining a
versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the
Atmel AT89S52 is a powerful microcontroller which provides a highly-flexible
and cost-effective solution to many embedded control applications.
The AT89S52 provides the following standard features: 8K bytes of Flash,
256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit
timer/counters, a six-vector two-level interrupt architecture, a full duplex serial
port, on-chip oscillator, and clock circuitry. In addition, the AT89S52 is designed
with static logic for operation down to zero frequency and supports two software
selectable power saving modes. The Idle Mode stops the CPU while allowing the
RAM, timer/counters, serial port, and interrupt system to continue functioning. The
Power-down mode saves the RAM contents but freezes the oscillator, disabling all
other chip functions until the next interrupt or hardware reset.
15
FEATURES:-
8 KB Reprogrammable flash.
32 Programmable I/O lines.
16 bit Timer/Counter—3.
8 Interrupt sources.
Power range: 4V – 5.5V
Endurance : 1000 Writes / Erase cycles
Fully static operation: 0 Hz to 33 MHz
Three level program memory lock
Power off flag
Full duplex UART serial channel
Low power idle and power down modes
Interrupt recovery from power down modes
256 KB internal RAM
Dual data pointer
16
2.TSOP1738 (INFRARED SENSOR)
Fig. Infrared Sensor
Description:
The TSOP17.. – Series are miniaturized receivers for infrared remote control systems. PIN diode and preamplifier are assembled on lead frame, the epoxy package is designed as IR filter. The demodulated output signal can directly be decoded by a microprocessor. TSOP17.. is the standard IR remote control receiver series, supporting all major transmission codes.
Features:
Photo detector and preamplifier in one package
Internal filter for PCM frequency
Improved shielding against electrical field disturbance
TTL and CMOS compatibility
Output active low
Low power consumption
High immunity against ambient light
Continuous data transmission possible (up to 2400 bps)
Suitable burst length .10 cycles/burst
Block Diagram:
17
Fig. Block Diagram of TSOP 173
Application Circuit:
Fig. Application circuit
18
3) 555 (TIMER IC):
Fig. Timer IC (555)
Description
The LM555 is a highly stable device for generating accurate time delays
or oscillation. Additional terminals are provided for triggering or resetting if
desired. In the time delay mode of operation, the time is precisely controlled by
one external resistor and capacitor. For astable operation as an oscillator, the free
running frequency and duty cycle are accurately controlled with two external
resistors and one capacitor. The circuit may be triggered and reset on falling
waveforms, and the output circuit can source or sink up to 200mA or drive TTL
circuits.
19
Features:
Direct replacement for SE555/NE555
Timing from microseconds through hours
Operates in both astable and monostable modes
Adjustable duty cycle
Output can source or sink 200 mA
Output and supply TTL compatible
Temperature stability better than 0.005% per °C
Normally on and normally off output
Available in 8-pin MSOP package
Applications:
Precision timing
Pulse generation
Sequential timing
Time delay generation
Pulse width modulation
Pulse position modulation
Linear ramp generator
4) LTS 542 (7-Segment Display)
20
Description:
The LTS 542 is a 0.52 inch digit height single digit seven-segment display.
This device utilizes Hi-eff. Red LED chips, which are made from GaAsP on GaP
substrate, and has a red face and red segment.
Fig.7 Segment Display
Features:
Common Anode
0.52 Inch Digit Height
Continuous Uniform Segments
Low power Requirement
Excellent Characters Appearance
High Brightness & High Contrast
Wide Viewing Angle
5) LM7805 (Voltage Regulator)
21
Fig. Voltage Regulator
Description:
The KA78XX/KA78XXA series of three-terminal positive regulator
are available in the TO-220/D-PAK package and with several fixed output
voltages, making them useful in a wide range of applications. Each type employs
internal current limiting, thermal shut down and safe operating area protection,
making it essentially indestructible. If adequate heat sinking is provided, they can
deliver over 1A output current. Although designed primarily as fixed voltage
regulators, these devices can be used with external components to obtain adjustable
voltages and currents.
Features:
Output Current up to 1A
Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V
Thermal Overload Protection
Short Circuit Protection
Output Transistor Safe Operating Area Protection
6) RELAY CIRCUIT:
22
Fig. Relay
A single pole dabble throw (SPDT) relay is connected to port RB1 of the
microcontroller through a driver transistor. The relay requires 12 volts at a current
of around 100ma, which cannot be provided by the microcontroller. So the driver
transistor is added. The relay is used to operate the external solenoid forming part
of a locking device or for operating any other electrical devices. Normally the relay
remains off. As soon as pin of the microcontroller goes high, the relay operates and
releases. Diode D2 is the standard diode on a mechanical relay to prevent back
EMF from damaging Q3 when the relay releases.
23
FLOW CHART
Fig. 4.7 Flow Chart
24
If the sensor 1 is interrupted first then the microcontroller will look
for the sensor 2, and if it is interrupted then the microcontroller will
increment the count and switch on the relay, if it is first time
interrupted.
If the sensor 2 is interrupted first then the microcontroller will look
for the sensor 1, and if it is interrupted then the microcontroller will
decrement the count.
When the last person leaves the room then counter goes to 0 and that
time the relay will turn off, and light will be turned off.
25
PROGRAM
// Program to make a bidirectional visitor counter using IR sensor#include <reg51.h>#define msec 1unsigned int num=0;sbit dig_ctrl_4=P2^6; //declare the control pins of seven segmentssbit dig_ctrl_3=P2^5;sbit dig_ctrl_2=P2^6;sbit dig_ctrl_1=P2^5;sbit relay1 = P2^0;sbit pin = P3^7;
unsigned char digi_val[11]={0xFE,0x18,0x6D,0x3d,0x1B,0X37,0x77,0x1C,0xfF,0x3F};unsigned int dig_1,dig_2,dig_3,dig_4,test=0;unsigned char dig_disp=0;sbit up=P1^0; //up pin to make counter count upsbit down=P1^1; //down pin to make counter count down
void delay(int x){char y = 200;pin = !pin;while((x--))
{while((y--));}
}
void init() // to initialize the output pins and Timer0{up=down=1;dig_ctrl_4 = 0;dig_ctrl_3 = 0;dig_ctrl_2 = 0;dig_ctrl_1 = 0;relay1 = 0;TMOD=0x01;
26
TL0=0xf6;TH0=0xFf;IE=0x82;TR0=1;P0=0x00;}
void delay1() //To provide a small time delay {
TMOD=0x01; TL0=0x36; TH0=0xF6; TR0=1; while(TF0==0); TR0=0; TF0=0;}
void display() interrupt 1 // Function to display the digits on seven segment. For more details refer seven segment multiplexing.{
TL0=0x36; TH0=0xf6;
P0=0xFF;dig_ctrl_1 = dig_ctrl_3 = dig_ctrl_2 = dig_ctrl_4 = 0;dig_disp++;dig_disp=dig_disp%2;
switch(dig_disp){
case 0: P0= ~digi_val[dig_1]; dig_ctrl_1 = 1; break;
case 1: P0= ~digi_val[dig_2]; dig_ctrl_2 = 1; break;
27
case 2: P0= ~digi_val[dig_3]; dig_ctrl_3 = 1; break;
case 3: P0= ~digi_val[dig_4]; dig_ctrl_4 = 1; break;
}}
void main(){
unsigned int cnt=0; init(); relay1 = 0; dig_ctrl_2 = 0;dig_ctrl_1 = 0;
cnt = 0; relay1 = 1; delay(100); relay1 = 0; delay(100); while(1) { if(up==1)
{ cnt=0; delay(1000); if(down==1)
{ if(test<99)test++;
dig_2=test%10;dig_1=test/10;relay1 = 1;
} } if(down==1)
28
{ cnt=0;
delay(1000); if(up==1)
{ if(test>0)test--;
if(test == 0) { relay1 = 0; } dig_2=test%10;dig_1=test/10;
}}
}}
CONCLUSION
29
Here by we come to the end of our project “AUTOMATIC ROOM LIGHT CONTROLLER WITH BIDIRECTIONL VISITOR COUNTER”.
Application of this project
For counting purposes
For automatic room light control
Advantages of this project
Low cost
Easy to use
Implement in single door
Future Expansion
By using this circuit and proper power supply we can implement various
applications such as fans, tube lights, etc.
By modifying this circuit and using two relays we can achieve a task of
opening and closing the door.
BIBLIOGRAPHY
30
Reference Books
Programming in ANSI C: E BALAGURUSAMY
The 8051microcontroller and embedded systems:
MUHAMMAD ALI MAZIDI JANICE GILLISPIE MAZIDI
The 8051 microcontroller: KENNETH J. AYALA
Website
www.datasheets4u.com
www. datasheetcatalog .com
www.8051.com
31