keyless door lock system

KEYLESS DOOR LOCK SYSTEM

B ANUSHA

CHITHRAJA RAJAN

JISHNU J


INTRODUCTION Security is a prime concern in our day-today life. Everyone wants to be as

much secure as possible. Due to increased crime in our country, everyone is worried about their safety. You need to be secure and safe not only when you are away from home, but when you’re home. Usually, people ignore the fact that they are monitored when alone at home. The crimes are increasing day by day and these burglars are just waiting for a chance to sneak into your house and steal your valuables.

An access control for doors forms a vital link in a security chain. The system consists of a code lock system, an alarm system and a driver circuit to open and close a gate. The lock system makes use of a pin to grant access to individuals. The pin is chosen by the individual who wants to secure the door. In some cases multiple pins can be used to secure the same door. The best of these models include the lock and the keypad all on one unit. The pin can be entered through an attached keypad or through a mobile phone device .since a mobile phone can be used to control the system, it has the advantage that it could be remotely controlled from any place that has network coverage. It has the capability to detect unauthorized entry and to inform the same using a buzzer alarm.


PROPOSED SYSTEM FEATURES A few special features of this system are described here :1. The lock can be triggered by a number keypad or a

mobile phone.2. The gate can be automatically opened if the correct

code is entered.3. Any forceful entry can be detected using a buzzer

alarm.4. Indicators are provided to indicate the status of the lock

and the buzzer alarm.


CIRCUIT DEVELOPMENT AND DESIGN

BLOCK DIAGRAM:

KEYPADOR

MOBILE PHONE

CODE LOCK

MOTOR DRIVE

SYSTEM

ALARM SYSTEM

UNAUTHORISEDENTRY

UNAUTHORISED ENTRY


CIRCUIT DESCRIPTIONPOWER SUPPLY

The power supply section consists of 230V 1A transformer used to step down the 230V to 12V.This step down voltage of the transformer is regulated using 12V and 5V linear regulators for producing 12V and 5V regulated DC.

CODE LOCK SYSTEM

The system comprises of a number keypad and a mobile phone

to enter the code and a circuit that responds to the right sequence

of four digits that are keyed in.

MOTOR DRIVE SYSTEM

This section of the circuit controls the opening and closing of

the gate based on the code entered through the keypad or mobile

phone.

ALARM SYSTEM

This block detects unauthorized entry into the parking lot and

informs the same with the help of the buzzer alarm.


CIRCUIT DIAGRAM


WORKINGCODE LOCK

The code lock responds only to the right sequences of four digits that are keyed in remotely. If a wrong key is pressed, it resets the lock .The lock code can be set by connecting the line wires to the pads A,B,C and D. For example, if the code is 1734, connect line 1 to A, line 7 to B, line 3 to C, line 4 to D and the rest of the lines to the reset wire.

The circuit is built around two CD4013 dual D flip flop ICs. The clock pins of the four flip flops are connected to the A, B, C and D lines. The correct code sequence is realized by clocking points A, B, C and D in that order. The five remaining switches are connected to reset pad which resets all the flip flops. Touching the key pad switch A/B/C/D briefly pulls the clock input pin high and the state of the flip flop is altered. The Q output pin of each flip flop is wired to D-input pin of the next flip-flop while D input of the first flip-flop is grounded. Thus ,if correct clocking sequence is followed ,then low level appears at Q2 output of IC2.This logic zero output drives the transistor BC557 to conduction state. The reset keys are wired to set pins 6 and 8 of each IC. Power-on-reset capacitor C1 has been added as the state of Q output is indeterminate during switching on operation.


TRIGGERING OF THE LOCK

USING NUMBER KEYPAD-The desired code is given as the clock inputs of the D-flip flops.The switches of the keypad are connected to the clock pins in the desired order. The remaining switches of the keypad are shorted and connected to the shorted set pins of the D flip flops.The other end of all the switches are connected to the input voltage.

USING MOBILE PHONE-This section consists of a DTMF decoder CM8870,1x16 DEMUX 74154 and an inverter 7404.When a button is pressed in the mobile phone, a tone corresponding to the button pressed is heard. This tone is called ‘Dual Tone Multiple Frequency’(DTMF) tone.DTMF assigns a specific frequency(consisting of two separate tones) to each key so that it can be easily identified by the electronic circuit. The signal generated by the DTMF encoder is a direct algebraic summation of the amplitudes of two sine waves of different frequencies. For example: pressing ‘5’ will send a tone made by adding 1336 Hz and 770 Hz to the other end of the line.


TONES AND ASSIGNMENTS IN A DTMF SYSTEM

The received tone is processed by the DTMF decoder CM8870.All types of 8870 series use digital counting techniques to detect and decode all the 16 DTMF tone pairs into a 4-bit code output. The built- in dial tone rejection circuit eliminates the need for pre-filtering.When the input signal given at pin 2(IN-) in single-ended input configuration is recognized to be effective, the correct 4-bit decode signal of the DTMF tone is transferred to Q1 (pin 11) through Q4 (pin 14) outputs.


MOTOR DRIVE CIRCUITThis motor drive circuit is used to control the opening and closing

of a gate depending on whether the code lock is activated or reset.This section consists of a comparator LM324,motor driver L293D and an LDR.The inputs to the motor driver are provided by the transistor output and a light source -LDR combination.

When the gate is closed,the light source is placed in such a way that light falls on the LDR.Therefore,the voltage across the LDR which is given as one of the motor driver inputs,will be LOW.The transistor output ,which is the other input to the driver,is LOW under locked condition and goes HIGH when the correct code is entered.Thus,all the four possible input combinations can be applied and the resulting effect is as follows:


ALARM CIRCUIT The alarm system consists of a non-inverting buffer 4050B,AND

gate 7408,a buzzer alarm and a few passive components.The gate remains connected to ground under closed position.When the gate is in closed position,there is no charge across the capacitor and hence the voltage across the capacitor ,which is used as one of the inputs to the AND gate,will be LOW.The other input to the AND gate is the transistor output.So,in closed position,the output of the AND gate will be LOW and the buzzer alarm is not activated.When unauthorized entry occurs and the gate is forced to open,the gate gets disconnected from ground.The capacitor starts charging and hence one of the inputs of the AND gate goes HIGH.Under locked condition,the other input to the AND gate is high and therefore,the output of the AND gate becomes HIGH which triggers the buzzer alarm.


PCB LAYOUT


CABINET DESIGN

Length - 24 cmBreadth - 18 cmHeight - 10 cm


ADVANTAGESNo keys to be lost, stolen or copied.Can be locked using keypad or using mobile phone.Automatic door opening and closing.Saves time and energy.Need for a watchman is eliminated.Gives an indication of unauthorized entry.Can be installed easily.Cost efficient.


LIMITATIONSIf the pin is forgotten the system cannot be accessed.Pin code can be changed only by the system designer.


COMPONENTS USEDICs

CD4013

CM8870

74154

CD4050B

LM324

L293D

7404

7408

7805

ACTIVE COMPONENTS

BC557

1N4001

Red LED

Green LED

PASSIVE COMPONENTS

Resistors

4.7 M

1 k

100 k

10 k

18 k

270

150

Capacitors


CONCLUSION The circuit we have presented proves to be highly

advantageous and innovative. This is a novel idea and finds great use in our day to day life. The keyless door lock system is intended to bring down the number of ever-increasing thefts in a cost-effective manner.

This concept of mini-project helped us to realize the advantages and disadvantages of working as a group. It was a whole new experience for us to the development, designing and fabrication of the circuits and it also provide a new insight into scope and development, trends and features of modern electronics.


REFERENCESwww.electronicsforyou.comwww.hobbycircuits.comwww.nationalsemiconductors.comELECTRONICS PROJECT VOL 23


THANK YOU

keyless door lock system

Documents