LED Flasher Unit

Why has LED display unit gained so much of acceptance and popularity?

• Low energy consumption• Low maintenance • Small size of LEDs

Has led to uses as status indicators and displays on a variety of equipment and installations

Large-area LED displays are used as stadium displays and as dynamic decorative displays.

Thin, lightweight message displays are used at airports and railway, buses, trams, and ferries stations.

LED flasher or display units find immense use in billboards, stadium displays, status indicators, indicators at airport and railway stations and many other ways…

•  Red or yellow LEDs are used in indicator and alphanumeric displays in environments where night vision must be retained.

• LEDs are used as street lights and in other architectural lighting where colour changing is used.

• Because of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses.

ARDUINO

What is Arduino?

• Arduino is an open-source computer hardware and software company, project and user community that designs and manufactures microcontroller-based kits for building digital devices and interactive objects that can sense and control objects in the physical world.

• The boards feature serial communications interfaces, including USB on some models, for loading programs from personal computers.

• For programming the microcontrollers, the Arduino project provides an integrated development environment (IDE) based on the Processing project, which includes support for the C, C++ programming languages.

The Arduino board.

• Inexpensive - The least expensive version of the Arduino module can be assembled by hand, and even the pre-assembled Arduino modules cost less than $50

• Cross-platform - The Arduino Software (IDE) runs on Windows, Macintosh OSX, and Linux operating systems.

• Simple, clear programming environment - The Arduino Software (IDE) is easy-to-use for beginners, yet flexible enough for advanced users to take advantage of as well. For teachers, it's conveniently based on the Processing programming environment, so students learning to program in that environment will be familiar with how the Arduino IDE works.

• Open source and extensible software - The Arduino software is published as open source tools, available for extension by experienced programmers. The language can be expanded through C++ libraries, and people wanting to understand the technical details can make the leap from Arduino to the AVR C programming language on which it's based. Similarly, you can add AVR-C code directly into your Arduino programs if you want to.

• Open source and extensible hardware - The plans of the Arduino boards are published under a Creative Commons license, so experienced circuit designers can make their own version of the module, extending it and improving it. Even relatively inexperienced users can build the breadboard version of the module in order to understand how it works and save money.

TYPES OF CIRCUITS AVAILABLE FOR LED FLASHER

The Alternative Approach...

The LED flasher can be designed using various electrical components like IC 555, CD 4060, transistors and such other components. Alternatively, it can also be designed using various microcontroller platforms too. In this project, we have implemented a LED flasher using Arduino.

A few possible circuit arrangements using electronic components are as follows.

CIRCUIT POSSIBILITY # 1:

Here, the circuit uses the popular Binary counter IC CD 4060 to flash the LEDs at different rates. Components C1, VR2 and R1 form the oscillator and the output pins 7, 5 and 4 become high / low sequentially. When one output turns high, a set of 3 LEDs turn on and when the same output turns off, the second set turns on. This sequence is similar in the other two sets of LEDs also but with different timings. The speed of the Flashing can be controlled through VR2.

CIRCUIT POSSIBILITY #2:

In this flashing led lights circuit, the LDR or photo-resistor is connected in such way that when the light intensity varies it will influence the flashing frequency and the brightness of the LEDs. T1, T2 = BC547, BC548, BC549 (any NPN transistor).

CIRCUIT POSSIBILITY #3:

The IC 1 (CMOS NE555) is wired as an astable multivibrator wired at a duty cycle of 50% and 4Hz frequency and drives LEDs D1 to D6.The second IC, IC2 (CMOS NE555) is working as a trigger pulse inverter and drives LEDs D7 to D12.The circuit is arranged such that the ICs sink the current consumed by the LEDs. At low operating voltages like 3V, the CMOS NE 555 performs better when arranged in sinking mode rather than in sourcing mode. The LED D13 remains permanently ON.

CIRCUIT POSSIBILITY #4:

By connecting the LED’s to different outputs they will flash one at a time but at different rates to each other (each output half the frequency of the previous one) and will not be all “ON” or all “OFF” together making it ideal for our simple LED flasher circuit.

By using divide-by-2 frequency divider/counters, with multiple LED’s connected to their outputs, it is possible to produce a twinkling star or flashing lights effect or any LED flashing lights display of your choice depending upon which ripple output you connect the LEDs to and how you physically arrange them.

Output : The counters outputs Q1 to Q12 have the ability to either “Sink” or “Source” a load current of up to a maximum of about 15mA, which is sufficient to directly drive the LEDs. The ability of the 4040 counter to both “Sink” (absorb) and “Source” (supply) current means that the LEDs can be connected between the output terminal of the counter and the supply to sink the load current or between the output terminal and ground to source the load current. 

WHY ARDUINO?

We chose Arduino implementation because of the following advantages o conventional bread board circuits or implementation on other microcontrollers :

• The whole point of the "Arduino Platform" is to allow for easy and fast prototyping. Being able to just hook up an LCD and be able to display messages on it in a matter of minutes, instead of hours, is just amazingly powerful and convenient when you have an idea in your head and just want to see if it works.

• For prototyping, the Arduino platform gives you a lot of pre-wiring and free code libraries that will let you concentrate on testing your idea instead of spending your time building supporting circuitry or writing tons of low level code.

• The greatest advantage is having the hardware platform set up already, especially the fact that it allows programming and serial communication over USB. This saves me the trouble of having to do my own PCB (which can cost more than an Arduino) or bread boarding.

TYPES OF LEDs

A Light-Emitting Diode (LED) is a two-lead semiconductor light source.

It is a p–n junction diode, which emits light when activated. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the colour of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.

The electronic symbol for the same is:

The physical appearance of the same is:

What is a LED?

DESCRIPTION OF THE LED USED IN THE PROJECT

Surface Mount LEDs are cost-efficient solutions for low-power, compact designs. The products come in a variety of available colour, lens, and package types and are highly durable.

An LED Strip Light (also known as an LED tape or ribbon light) is a flexible circuit board populated by surface mounted light-emitting diodes (SMD LEDs) that usually comes with an adhesive backing.

METHODOLOGY

The coding for blinking LED was written in the terminal and executed using Arduino cable and board. The letters “GDGU” were made using Acrylic Sheet.

The programmed LEDs were fit on the periphery of the alphabets. The entire set up was mounted on sun-board for rigidity and efficient display.

The various intricate details of circuit diagram, working and coding are provided extensively in the report.

Work In Progress.....

WORKING OF THE PROJECT

FUTURE SCOPEAPART FROM THIS BASIC PROJECT, WHAT CAN THIS IDEA BE FURTHER EXPLOITED FOR?

1. higher order LED displays (a) Christmas lighting purpose(b) flashing or sequential display

billboards and signs.

2. a token display unit3. Night-time display and warning boards for the

ease of people

4. Using ARDUINO platform, we can work on high level projects like:

(a) ‘Home Automation System’ (b) ‘Transform convertors’ etc.

Not only this, the applications are wide enough and can leave one wondering!

REFERENCES

• http://en.wikipedia.org/wiki/Arduino• http://www.electroschematics.com• http://www.circuitstoday.com • http://www.electronics-tutorials.ws/counter/simple-led-flasher.html• http://www.sparkfun.com• http://www.quora.com• http://www.instructables.com• http://www.varesano.net• http://www.academia.edu• http://pidelectronics.com• http://paolaguimerans.com• www.mouser.in • www.en.wikipedia.org • www.instructables.com• http://www.wisegeek.org/what-is-acrylic.htm• www.quora.com