RECOMMENDATIONS

Using Matrix Display

For this project, it is recommended to use matrix display than using one by one of leds and we have to construct the leds arrangement according the design of logo. By using Matrix display, there is no complication to design the logo. The programming to view the pattern of led display on matrix board. In addition, it can save a lot of money than buying many super-bright leds.

Using PCB Board

The standard design of Led display board basically use strip board (single holes). There have many problems when using basic strip boards, so, have to improve using PCB board or Etching process. It is more easier to use than using strip board. Using PCB or etching board, to design the layout of led display of UNIKL Logo, it is more suitable than using strip board. The PCB board can design the pattern of Logo smoothly. So, by using it, the design of the logo will be perfectly designed according the model of the logo. Period of time to design the logo on board will be taking a short time.

Experimental Results

Latch up triggered

The result signal of the Leds display when the changes of animations produced. I had used the experimental circuit results to prove that how the animation working in the circuit based on the signal from result in oscilloscope. The first signal is triggered to latch up new data for column. The second signal is activated to low for turning on the column for led matrix. The frequency for one frame is 30 ms.

Signal from driver circuit

The first signal is generated from driver circuit. The signal is set to active within 5 ms and exponentially going down within 20 ms. The timing is crucial to ensure the Led matrix is protected from over current.

Block Diagram for Led Animation

Block Diagram

On the right of the diagram is the LED matrix which consists of seven rows of 64 LEDs. Each of the rows has a switch circuit, which supplies current from the power supply when activated. These row

switches are controlled by a set of seven latches which receive data from the data bus. An eighth latch is used to activate the piezoelectric sounder circuit. 

  

The columns also have switch circuits, these being designed to sink current to ground when activated. The column switches are also controlled by latches. Arrange in eight groups of eight. Each group can be written to from the data bus under the control of eight column group select lines which make up the select bus. Both the data and select busses are buffered before connection to the column latches. 

On the left side is the CPU circuitry. The clock circuit provides the master timing reference. While the reset circuit ensures that the CPU starts executing program instructions from the beginning when power is first applied. The EPROM and RAM are connected to the CPU via common address and data busses and are selected under the control of the memory address decoder circuit.

The I/O (lnput/Output) address decoder circuit uses control signals from the CPU to select the row latches. The column latches and the keyboard buffer. The keyboard buffer reads both the keypad and the DIL switches simultaneously. The data bus, select bus and the row latch signals are connected to the display section via a 20-r.r'ay ribbon cable. While a I/O-way rib-'on cable is used to connect the keypad to the keyboard buffer.

LED display signs can be programmed to have changing images or lettering, or animated graphic displays that keep alternating as different lights come on and off. Neon signs, while they can be made to show an animated design with different tubes switching on and off, have less overall versatility. LED display signs tend to be seen as modern, but often rather clinical and cold. Neon signs are perceived as warmer and more inviting, with a retro feel that often suits small businesses attracting individuals.

The smallest unit of the LED display screen that can be controlled and can be turned off or on at various brightness levels. The full name of pixel is “picture element”. In a 3 colour LED display, the pixel is made of 3 different colours – red, green and blue. Each part is made up by one LED or several LED’s, in theory that the different 3 colours can display every colour by adjusting the led brightness.  Therefore, pixels are points of light that illuminate together to form letters, words, graphics, animation and video images.

How Led Matrix Works?

Circuit Diagram

Led driving circuit using 5v supply without any damage. If we connect directly the 5v supply to an LED, all the source current flow through LED and it will burn out the LED. So we need a resistor in series with LED. In electronics, load current always plays an important role to design a circuit. Here the load current is the current flowing through LED. So, the circuit need 20mA current to flow through the LED for better brightness, therefore the load current is 20mA and LED takes only 2v to ON.

Structure of a 8x7 LED 

To drive the rows of the LED matrix, some microcontrollers doesn’t have enough output voltage/currents. Therefore we need to place a transistor array or a latch between the led matrix and microcontroller. Generally for simple LED Scrolling board latch is enough to provide sufficient current to the LEDs. Here, we have used 8-bit latch for this purpose. Each output of the 8-bit latch is able to provide current greater than 20mA which is enough to produce sufficient brightness to the LED.

 VIDEO OF ANIMATION LED

UNIKL Logo: Design And Construction

Arrangement of Leds

For the UNIKL Logo display, arrangement for led based on the display of the logo. The UNIKL Logo used three strip board to divide part of the Logo Display. When all parts attached, it will display UNIKL Logo.

Arrangement of Leds depends on the colours and the connections of the circuit. For this project, I used 7x8 arrangement matrix led. The 7x8 arrangement means that for one block of diagram or the colours, it has 56 leds. So, one rows represent one colour for example first rows, represent red colour on leds display and for the second row, for red colours too but different animation that had programmed on it. Every each of board has different colour of leds and each board has IC that represented as column driver circuit. Every connection or rows of leds will connected to driver circuit based on schematic diagram. I have to use 56 leds for each blocks of leds so it can display animation of leds with best results.

8x8 LED Matrix Construction

By using single array of LEDs we can generate different type of patterns. When arrange the LED arrays side by side with multiplexing technique, it is also possible to generate letters, symbols, numbers, pictures, animations also. The LED Dot Matrix can be constructed by connecting all the anode terminals of LED’s together in each row and all the cathode terminals are joined together in each column. The entire cathodes are connected together and should be grounded. Each LED anode is driven by manual switches or by microcontroller. The microcontroller is programmed to generate different patterns on these LEDs. The individual LED current is summed up and a large current flow into the ground terminal 

THEORY OF LED DOT MATRIX DISPLAY

In a dot matrix display, multiple LEDs are wired together in rows and columns. This is done to minimize the number of pins required to drive them. For example, a 8×8 matrix of LEDs (shown below) would need 64 I/O pins, one for each LED pixel. By wiring all the anodes together in rows (R1 through R8), and cathodes in columns (C1 through C8), the required number of I/O pins is reduced to 16. Each LED is addressed by its row and column number. In the figure below, if R4 is pulled high and C3 is pulled low, the LED in fourth row and third column will be turned on. Characters can be displayed by fast scanning of either rows or columns.

Example of using Dot Matrix

Dot Matrix

Introduction of the purpose LED Display

EXAMPLE OF LED'S

UNIKL LOGO

The Logo display is used for commercial advertisement billboard. The unique Logo display is very attractive which can promote the brand of the products. Super bright LED with multi-colours are arranged to highlights the colours of the logo. A smart micro-controller is used to program animation algorithm for different animation features. This potential device has very unique commercial value for companies to promote their logo and products. The first proposed logo for this FYP would be UniKL.

This project is about to developing LED signs use a modular system, it’s suitable for a number of purposes. In most of cases though, the programmable LED signs are used for advertising reasons. Smaller businesses usually make use of this medium as their outdoor sign. Meanwhile, numerous savvy entrepreneurs buy advertising space in high traffic locations to be able to promote their businesses there.

It is also easy to understand the mechanics of using programmable LED signs. It’s a plug-and-play system so virtually anyone can do the installation given the right instructions.