Design and Construction of Automatic Hand Dryer With Temperature Display
Chapter One
OBJECTIVE OF THE PROJECT
The major objective of this project is to design and implement automatic hand-dryer with temperature display. The project is also aimed at familiarizing the graduates of Computer Engineering in electronic system designs involving digital systems and random logic. The project is aimed at acquainting the young graduate on the ethics of Engineering, technical and scientific writing which forms the nucleus of Engineering professional practice. It is also aimed at testing/accessing the young Engineers ability to realize engineering project within a specified time.
CHAPTER TWO
LITERATURE REVIEW
HISTORICAL DEVELOPMENT OF THE PROJECT
Automation is a vital aspect of industrial electronic and this has gained a holistic approach. This aspect of industrial electronics has contributed immensely to the world’s technological growth. Alan Muinford (1993).
Hand-dryers are electrical devices found in public wash rooms which are used to dry hands. They may either be operated by a push button or automatically using opto-coupler it has been popular with industries for their apparent economies. According to manufacturers, hand-dryers can reduce cost by nearly 99%. They require very little maintenance as compared to paper towel which must be removed. The cost of acquiring and using this system is borne in the power consumption of the dryer. The lowest energy hand dryer uses 1 watt-hour per dry and is ratted 0.24KW.
The earliest hand-dryer was patented in 1921 by three Engineers for Air Dry Corporation of Groton, New York. Tis machine was sold as a built in model or free standing floor unit that consisted of an inverted blower controlled by a floor pedal.
It was later populated by George Clement in 1948. In 1993, Mitsubishi Electronics introduced a new type of hand-dryer that blows jets of air on both sides of the hand, pushing the water off rather than evaporating it.
Research carried out on rate of spread of bacterial count by different drying methods revealed that:
(a) Jet Air dryer which blows air at the rate of 640Km/hr was able to blow out micro-organism from the hand and deposit them on the wash room environment, two meters away even on the next user.
(b) The use of a ware air hand dryer spread bacteria count up to 0.25M away from the user
(3) Paper dry towel showed no significant spreading bacteria on the environment.
A paper has it that hot air dryers had the capacity to increase the bacteria count on the skin while paper rolled does not.
Considering the chronology in the development of hand dryers, I deemed it necessary to embark on the project design and implementation of automatic hand dryer with temperature display. This system will be capable of drying a hand using warm air and display the temperature of the warm air.
CHAPTER THREE
SYSTEM DESIGN AND ANALYSIS
DESCRIPTION OF THE SYSTEM BUILDING BLOCKS
This project design and implementation of an automatic hand-dryer with temperature display capable of drying a wet hand placed in the line of sight of the electronic eye. This system is designed in several building blocks which are combined to form one functional unit. The first block is the sensor unit which is realized with Laser diode coupled on to LDR. The second block is the signal conditioning unit which generates a control logic used to trigger/switch both the hand-dryer and temperature meter simultaneously. The third block comprises of a transistor and electromagnetic relay that actuates the blower. The fourth block is the IC Linear Temperature Sensor that is installed at the front of the blower to receiver the warm air. The fifth block is the Quad-comparator with hysteris which amplifies the output signal of the sensor. The sixth block is a frequency generator achieved with Ne555 timer in Astable mode while a 2-digit decimal counting unit counts the frequency which corresponds to the temperature of the warm air. All these blocks are cascade pertinently to achieve one functional automatic hand-dryer with temperature display. (Sandra Kay Miller 1996).
CHAPTER FOUR
IMPLEMENTATION, TESTING AND RESULT
IMPLEMENTATION
This system was constructed in seven different blocks all combined to form one functional unit.
The input interface: the components of this unit is mainly the electronic eye/opto coupler which is achieved with Laser diode coupled onto LDR that functions as the sensor. These components are tested using digital multimeter to ensure they are in good working condition. After testing the components, they were mounted on breadboard as specified on the circuit diagram. The control circuit which consists of the signal conditioning unit and frequency generator were implemented using same step as above. The different modules were tested individually. After which they are transferred to the vero board for permanent soldering. The ICs used in the design were mounted on heat sink to prevent thermal runaway during soldering. The power supply unit was implemented using the four primary steps in realizing +5v regulated DC power supply unit. The output interfaces which comprises of the transistor driver and electromagnetic relay which switches the blower was implemented directly on the overboard after testing the individual components using multimeter. The decimal counting unit (DCU) was also constructed on a separate overboard for ease and simplicity.
CHAPTER FIVE
SUMMARY, CONCLUSION AND RECOMMENDATION
SUMMARY OF ACHIEVEMENT
This project design and construction of automatic hand dryer with temperature display was constructed using top-down methodology. The power supply unit was constructed and tested (it did not deviate from the expectation at all). The opto-coupler and control logic unit worked out perfectly. The driver section, switching relay and the actuator responded positively. The decimal counting unit (DCU) was properly constructed to display 2-digit value of the temperature of the blown out air in degree centigrade (0C).
The overall system was tested, packaged and re-tested. And it has not deviated from the aim by any means.
In the process of developing this project work, I encountered some problems, but was resolved by conceived ideas. Some of the problem I encountered are as follow:
(i) Burn-out chips: Some ICs underwent thermal runaway as a result of direct soldering: but I overcame this problem by mounting them on IC sockets.
(ii) Lack of circuit development resources: I consulted senior colleagues who assisted in designing and simulating the circuit using Proteus – 7 circuit simulator.
(iii) Poor funding: I sought for financial help for friends and well-wishers.
(iv) Project report development: This was most challenging but was overcame by constant meeting/advice/directive from my supervisor.
CONCLUSION
The project design and construction of automatic hand-dryer with temperature display was realized with ease and within the stipulated time. It was realized with passive and active component available in the local market. The system gave me an insight in electronic system design and manufacturing. Further modifications of this design should be centered on miniaturization since this project so completed is big and somewhat portable. It can be used in Restaurants, Bars, and Homes and in comfortatations (conveniences). The result of this project being an automatic hand-dryer which can dry-up a wet hand placed under its vent and also display the temperature of the blow out air in degree centigrade.
REFERENCES
- Alan Muinford (1993): The IT manager: Security And Training, Prentice-Hall, Inc. New Jersey. Allen Palms (1999): Lock: Locks and Locked, Time square, United Kingdom.
- Assa Abloy (1997): Door Opening Solution, Whispering Fuse, Maryland.
- Baker C, R. (1999): An Analysis of Fraud on Locking Devices, Spectra Inc, New York.
- Dennis Roddy and John Coolen (2002): The same Small World of Microcontrol, Computer prints, New York.
- Irving Gottlieb (1973): Basic Electronics procedures, Foulshma-Tab Limited, USA.
- Jeffrey Whitten, and Lanni Bentley, (2001): System Analysis and Design, (faith Edition), Me Graw Hill Publishers, New York.
