Design and Construction of Electronic Display Unit
Chapter One
PROJECT OBJECTIVES
Depending on one’s intention, microcontroller-based digital advert display systems have many aims and objectives.
For this particular project, the aim is to display moveable coded letters that welcome a visitor to the department which displays DEPARTMENT OF ELECTRICAL ELECTRONICS ENGINEERING
CHAPTER TWO
LITERATURE REVIEW
This chapter will give an insight into the meaning microcontroller based digital advert display system, ways by which it could be achieved, here some discrete components such as resistors, capacitors and transistors with integrated circuits (IC) were used to make this work and it’s wiring easier to understand. By the end of this chapter, one would stand a better chance of having an understanding of what microcontroller based dot matrix information display system is all about.
COMPONENT DECRIPTION
The implementation and design of microcontroller based Dot matrix information display system has sub units such as:
- The regulated power supply
- The Micro-controller unit.
- The buffering unit.
- The display section
THE REGULATERY POWER SUPPLY
Digital ICS work on regulated power supply and because ICS are used in this design, a regulated power was used for this work. The major components that make up a complete regulated power supply are the step down transformer, rectifier, circuit, filter circuit and a regulator.
STEP DOWN TRANSFORMER
A transformer is a device consisting of two closely coupled coils called primary and secondary coils. In this design the value of the transformer used is 240v/12v center tapped transformer with current rating of 1000m. A step down transformer is the AC mains supply voltage to a useful lower value with the output still remaining an AC signal.
Thus a step down transformer steps the voltage down from 240V to 15V and both operating at the same frequency.\
CHAPTER THREE
DESIGN ANALYSIS AND SYSTEM IMPLEMENTATION
THE BLOCK DIAGRAM OF PROJECT
the block diagram of project
The design analysis of this work, microcontroller based digital advert display system was carried out in section. There sections are: the regulated power supply, the control section, the display section and the switching section.
THE REGULATED POWER SUPPLY
The regulated power supply consists of a step down transformer, which pulls down the mains 240 to 12 needed to drive the whole device.
CHAPTER FOUR
TESTING AND RESULTS
TESTING
Testing work after design is necessary in any design. The essence of testing is to ensure that what the designer had in mind at the onset of the design that is the initial aim of the work appropriately and accordingly satisfied. Testing of this work has done section by section for accurate records. Most of the testing carried out was done with digital meter to ensure that there was no short circuit between the components connected. The power section was first tested to ensure appropriate power supply to the system. The program stored in the microprocessor was also tested to find and correct mistakes to get it working properly. This is done by burning the program into the microcontroller, install the microcontroller in the system, run the program will be modified erase and the microcontroller reburn. This testing of the program will be repeated as many times as necessary until the system is operating properly.
CHAPTER FIVE
PACKAGING, SUMMARY, CONCLUSION AND RECOMMENDATION
PACKAGING
Metal casing was used for packaging of this project. The tools used here are saw, screen, nails and drilling machine. The metal material was cut into small rectangles and big rectangles to serve as the base, top and side covers. Drilling machine was used to drill holes for screw nails. Provisions were also made for the power supply leads, display and electronic switches.
For this project, packaging with metal was considered most suitable, taking into consideration its availability and cost of material. Other things considered prior to determining the size of the package are:
- The size of electronic switches
- The size of Vero board
- The size of the display screen.
- Provision for 240/12v ac transformer was provided for the device.
SUMMARY OF THE PROJECT
This project, microcontroller based dot matrix advert display system was designed to welcome a visitor to computer engineering department ESUT. All steps I took in the design of this project were accomplished by taken each unit at a time in the design process, as I stated earlier that the project is made up of several sub units.
The power supply unit was the first unit I designed before other sub units followed suit. However microcontroller based remote control dot matrix advert display to display vital information in a more fancied digital and colored form cannot be over emphasized. Hence companies and corporate organizations have taken advantage of this.
SUMMARY OF ACHIEVEMENT
My achievement is that I have now got the knowledge about how micro-controller can be used to design a beautiful project of this nature. Also I realized the reason why assembly language is better preferred to a more complex and complicated C-language. In the design of a micro-controller based project like this one.
PROBLEMS ENCONUTERED AND SOLUTION
There are both major and minor difficulties encountered during the design of this project.
Major:
- NONAVAILABILITY FACTOR: I find it very difficult to get the appropriate micro-controller for this project. This made me to walk extra mile by making a special order that costs me much than I estimated
- THE UNSTEADY POWER SUPPLY: there was unsteady power supply and when supplied, the case of very low voltage. This actually put some delay in finishing the work within the project duration. However, I hired generator to complete the work thereby spending more than I planned to.
- COMPONENT FAILURE: The LEDs failed most times, including the capacitors and transistors, this happened during soldering, because these components cannot withstand very high temperature. Hence I replaced them with good ones.
MINOR:
- LACK OF FINANCE: The basic requirements for designing a project like this is cost intensive that I could afford presently. To this effect, the design of this of this project was limited to what I can control.
- SHORT CIRCUIT: there was too much short-circuiting, which resulted in the loss of some components. Hence I trouble-shoot and removed the affected ones only to replace them with new ones.
- SOLDERING: soldering was a problem of its own, I mistook the anode of the LEDs to the cathode on the course of soldering, this interrupted current flow, hence I made corrections where necessary and then re-soldered.
- POWERING: At a point, it failed to power using AC source but powers with a DC battery. Reading the transformer using the digital meter, I realized that it receives AC from the source but could not give out DC to the circuit. I had to change the transformer.
- At the first test, the display was working but its characters were up-side-down.
Solution: I de-soldered the seven connecting wires that go to the seven rows of the screen there by rearranging their sequence and I was able to overcome the difficulty.
- On rewriting the program, the project refuses to work.
Solution: Since this very fault started when I wrote a new program, I had to look into the program and made some corrections.
- With the new program, it started working but have some columns jumped.
Solution: I had to trouble shoot and discovered that two buffer ICs have some bad soldering which I re-soldered and the whole columns started working.
PRECAUTIONS
I took the following percussions
- I had to be very careful in drilling the prospect board by placing it on a flat object and also removing the drilling tool immediately the needed hole is made to avoid melting/breaking.
- Handling the ICs and the PIC needed much carefulness as their pins can easily break and make them useless.
- I had to measure the needed space for the resistors and the transistors to decide the spacing for the ICs.
- In Soldering the LED, I had to very careful to avoid being hurt from the heat they conducts trough the soldering iron which easily burns my hand at interval.
RECOMMENDATION
This project can further be improved to generate report on daily, weekly, monthly and yearly basis that this project could not do due to time constraint. Take an example; if the project were constructed to have an interface with PC it would be better.
CONCLUSION
Dot matrix information display is all about the distribution of information and entertainment in dot matrix format, usually including software that allows viewers to interact with text, symbols and images. Most forms of information can be published electronically by way of dot matrix information display, the advent of microcontroller have made it easier for us to display information in this format in a unique way.
REFERENCES
- ARIE VAN STAVEREN AND ARTHUR ROERMOND (2000)__ structured electronic design, springer publishers, 5th edition.
- BORAT (1997) –A course in digital processing, Wiley 6thedition
- EDWARD ROLL TUFT (1990) ___ Principles of information display, graphic press, 3rd edition.
- ENCARTA ENCYCLOPEDIA/PREMIUM 2009.
- LIM AND A. OPPENHEIM (1988) __ advanced topics in digital processing. Prentice Hall limited, New Delhi 2ndedition.
- JOSEPH GREENFIELD (1999) ___ digital electronic design Oxford University press 4th edition.
- TAKIS C. KESPARIS (2003) ___ electrical and computer engineering, central Florida USA, 7th edition.
