TIMER BASED CODE LOCKAkashdeep Singh#1, Alisha*2, Pratibha#3, Puneet Dewan#4

#ECE Department, Chitkara UniversityHimachal Pardesh

1akshdpsingh@gmail.com2alishabansal1994@gmail.com3effortgirl0909.pk@gmail.com

4puneet2147@gmail.com

Abstract— the necessity of a low cost electronic code lock system designed in co-ordination with other security measures is always there in our society to reduce the risk of theft. Keeping this problem in mind, we are working on a project on timer based code lock. We want to utilize the electronic technology to build an integrated and fully customized lock at a reasonable cost. We hope this project will be useful in keeping thieves, dacoits and other sort of dangers at bay.

Keywords— IC-555, Resistors, LED, Capacitors, Switches

I. INTRODUCTION

This system unlock the lock by using pre decide password, increase the security level to prevent an unauthorized unlocking .In case the user forgets the password this system gives the flexibility to the user to change or reset the password. This automatic password based lock system will give user more secure yet cost efficient way of locking unlocking system.

II. WORKING

An essential property of this electronic code is that it works in a monostable stage ie. Once triggered the output becomes high & remains for some period of time.In the 555 ic, pin 2 is triggered input pin which held below 1/3 of the supply voltage, drives the output to high stage.The threshold pin 6 held higher than 2/3 of the supply voltage, drives the output to low stage.

III. COMPONENETS

A. IC 555

555 is a very commonly used IC for generating accurate timing pulses. It is an 8pin timer IC and has mainly two modes of operation: monostable and astable. In monostable mode time delay of the pulses can be precisely controlled by an external resistor and a capacitor whereas in astable mode the frequency & duty cycle are controlled by two external resistors and a capacitor.

B. Resistors

Resistor is a passive component used to control current in a circuit. Its resistance is given by the ratio of voltage applied across its terminals to the current passing through it. Thus a particular value of resistor, for fixed voltage, limits the current through it.

C. Capacitors

Capacitor is a passive component used to store charge. The charge (q) stored in a capacitor is the product of its capacitance (C) value and the voltage (V) applied to it. Capacitors offer infinite reactance to zero frequency so they are used for blocking DC components or bypassing the AC signals.

D. LED

Light emitting diodes (LEDs) are semiconductor light sources. The light emitted from LEDs varies from visible to infrared and ultraviolet regions. They operate on low voltage and power. LEDs are one of the most common electronic components and are mostly used as indicators in circuits. They are also used for luminance and optoelectronic applications.

E. Switch

In electronics, an electronic switch is an electronic component or device that can switch an electrical circuit, interrupting the current or diverting it from one conductor to another.

IV. TOTAL COMPONENTS

Sr. No. Component Quantity1. IC 555 12. LED 13. SWITCHES 74. RESISTORS

(1M,1k,10k(2), 1k)5

5. CAPACIORS(1uf, 10uf,4.7uf)

3

V. ADVANTAGES

1. It is very simple in construction & so dependable.

2. Its weight is less easily bearable.3. It is perfect for locking that documents which

are used all times because it is easy to operate4. We can easily change the combination

password as we like best at any.

VI. FUTURE DEVELOPMENT

1. We can add voice feedback to open the lock.2. Complexity of the lock can be altered using

different no. of switches.

VII. CIRCUIT DIAGRAM

VIII. ACKNOWLEDGMENT

We would like to thanks to our university who gave us an opportunity to work on the project “Timer based code lock”. We like to acknowledge our teacher Miss. Monika Parmar who was always ready with a positive comment and for assisting with data collection for this project. We would also like to thank our friends and parents for their moral support.

CONCLUSION

It is always better to start every design with a good proposal, which will stand as a reference point to the work as it proceeds. The result of any design gives joy if aims and objectives are met. Since the project performed according to our need it is indeed satisfactory. This project can be really helpful in replacing old locks with new & advanced technology which can safeguard our necessary & important things. Thus, this design is a huge success.

REFERENCES

[1] http://www.engineersgarage.com/electronic-circuits/timer-based-code-lock

[2] http://en.wikipedia.org/wiki/Electronic_switch [3] http://en.wikipedia.org/wiki/555_timer_IC

[4] http://wiki.answers.com/Q/What_are_the_advantages_and_disadvantages_of_digital_code_lock