ABSTRACT..............................................................................................................................................2

ACKNOWLEDGEMENT...........................................................................................................................3

CHAPTER 1.............................................................................................................................................4

1.0 INTRODUCTION........................................................................................................................4

1.1 COMPANY BACKGROUND........................................................................................................4

1.2 COMPANY PROFILE..................................................................................................................4

1.3 CORPORATE CULTURE.............................................................................................................4

1.4 STRUCTURE OF TECHNOLOGY CENTRE....................................................................................5

1.5 EMPLOYMENT MIX..................................................................................................................6

1.6 PRODUCT PORTFOLIO..............................................................................................................6

1.7 MARKET SUMMARY.................................................................................................................6

1.8 CONCLUSION...........................................................................................................................6

CHAPTER 2.............................................................................................................................................7

2.0. INTRODUCTION.......................................................................................................................7

2.1. PERSONAL AND PROFESSIONAL DEVELOPMENT....................................................................7

2.2. KEY SKILLS DEVELOPMENT......................................................................................................8

2.3. PERSONAL DEVELOPMENT.....................................................................................................9

2.4 CONCLUSION...........................................................................................................................9

CHAPTER 3...........................................................................................................................................10

3.0 INTRODUCTION......................................................................................................................10

3.1 PRINTED CIRCUIT BOARDS.....................................................................................................10

3.2 SOLAR DRIER..........................................................................................................................14

3.3 EGG INCUBATOR....................................................................................................................16

CHAPTER 4...........................................................................................................................................24

4.0 CONCULSION.........................................................................................................................24

4.1 RECOMMENDATION..............................................................................................................24

REFERENCES........................................................................................................................................25

APPENDICES.........................................................................................................................................26

APPENDIX 1.....................................................................................................................................26

APPENDIX 2.....................................................................................................................................27

APPENDIX 3.....................................................................................................................................29

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ABSTRACTIn order to ensure that graduates will be able to meet employers’ expectations; students are required to undergo industrial internship for seven (7) months before entering the final year at Harare Institute of Technology (HIT).

The main purpose of this internship program is to bring professional experience to students in electronics science and technology and related areas of engineering; as well as to improve their engineering skills by means of observing technological developments and applications in professional areas, providing them with hands on training sessions within production environments and research laboratories in the organizations.The Industrial Internship Programme will allow employers to play an active role in developing the attributes and expertise required by the industry. The objectives of this programme are:

To enable students to integrate theory with practice To introduce students to work culture and industrial practices To provide opportunity for students to work with industrial practitioners To expose students to potential employers

This is an internship report in partial fulfilment of the Bachelor of Technology (Hons) Degree in Electronic Engineering. The report explains the training in several skills sets that pertain to Electronic Engineering the student gained during the internship period. Most of the skills sets focused on are those that the student had covered during the two and half years of theoretical learning at the Institute. The report is for the period from February 2013 to present (June 2013), at Harare Institute of Technology’s Technology Centre.

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ACKNOWLEDGEMENTThis attachment was possible thanks to the cooperation and support from a number of people, who have enabled me to gain much more than what the scholastic or industrial aspects of the program could have given. The student is grateful to them all, and would like to express his appreciation to the following people:

Mr. Parsons, for sharing enthusiastically with him his experiences in programming. The student is sincerely indebted to him for taking great pains to keep the student on the right track. His support and assistance contributed to the success of the project.

Mr. Leonard Mukumba for being extremely patient and for providing advice to the student on analogue and digital interfacing which was required for the success of the many projects.

Mr Tinashe Chamunorwa, my supervisor from Harare Institute of Technology, who has helped in coordinating with the administration staff and provide valuable assistance in logbook and report writing.

The student would also like to express his appreciation to all the staff and colleagues in the Electronic Engineering Department for their full support and assistance during the attachment, particularly Mr Peter Musiiwa for his advice in assembly programming. I would also like to thank my partners Mr Chitsvare, Mr Gweshe and Mr Kanyemba for their help and encouragement throughout the entire industrial internship.

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CHAPTER 1NATURE OF INDUSTRY AND INDUSTRY REQUIREMENTS

1.0 INTRODUCTIONThis chapter begins with explaining the purpose of the report; followed by its scope and limitations. It then goes on to give a brief introduction on the history of Technology Centre and the business unit the student was attached to, Institronics (Electronic Engineering Department). This chapter also covers the research goals of Harare Institute of Technology.

1.1 COMPANY BACKGROUNDHarare Institute of Technology was established in 1998 as a Technical Vocation Training Institute, in 2005 it was made a university. It went on to set its objectives, quoting some from Under Graduate Bulletin 2011 (page 2):b) The development, incubation, transfer and commercialisation of technology;c) Development of high level technical manpower;d) The establishment of production centres linked to departments and development of a Science Park; From the few objectives highlighted above The Technology Centre was established and commenced business immediately.

1.2 COMPANY PROFILE The Technology Centre (TC) is a strategic unit of Harare Institute of Technology (HIT) that was set up to promote (the development of) manufacturing activities from various academic units within the Institute as well as attending production orders from industry and commerce. Its other mandate is to give competence development training in technical and management courses to industry and commerce as well as the Small to Medium Enterprises (SMEs). The TC also promotes school-wide interdepartmental convergence that leads to establishment of various research groups in an interdisciplinary and multidisciplinary approach.

1.3 CORPORATE CULTURE Harare Institute of Technology’s uniqueness lies in providing practical oriented technology degree programmes that are underpinned by Technopreneurship, and facilitated by the state-of-the-art workshops, laboratories and facilities. HIT has focused on a plan that seeks to bring tangible results in a short period in research, technology transfer, incubation, and commercialisation for the rapid industrialisation of the nation through its Strategic Plan - Designing the Future.

1.3.1 THE VISION AND MISSION STATEMENT The Vision and Mission statement of the Technology Centre is derived from those of Harare Institute of Technology.

1.3.2 VISION To be the captain in innovation through professionalism.

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1.3.3 MISSION STATEMENT To promote cooperation towards Technopreneurial leadership in enterprise development that develops professionals and industrial services underpinned on integrity. 1.4 STRUCTURE OF TECHNOLOGY CENTRE The Technology Centre has two distinct and complimentary centres of excellence, which are the Technical Training Unit and the Production Unit. The Technical Training Unit work with the academic departments in order to provide tailor made programmes and customised short courses in response to industry’s needs. The Production Unit brings workshops and laboratories of all academic units together in an interdisciplinary and multidisciplinary approach to enhance research and development as well as maximising on production orders from industry and commerce. The Institute has registered a separate business entity called Institech-Holdings as a commercial vehicle that enables commercialisation of successful research and development key units. It has the following companies under its ambit.

Instifoods Institools Instisoft Instiherbal Institronics

The student was attached to the Institronics business unit. This unit is not yet functioning independently; it is operating under the Department of Electronic Engineering. In this report whenever the student mentions Institronics or Electronic Engineering they stand for the same organization otherwise Electronic Engineering Department is the academic department. The Institronics structure is illustrated below:

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Instiherbal

Technology Centre

Instifoods Instisoft Institronics

Vice Chancellor

TC Director

Department Chairman

Tech Instructor (workshop)

Tech Instructor (PLC Lab)

Tech Instructor (PCB Plant)

Tech Instructor (Analog/Digital)

Institools

1.5 EMPLOYMENT MIX The Technology Centre has a staff compliment of between 20 and 50 members amongst its holding units. The staff members comprise of permanent staff and contract workers who renew their contracts on annual basis. Worker engagement takes place through two main channels. a. Production briefings chaired by the Director of the Technology Centre every Monday morning at 9:00hrs. b. The workers committee elected by employees also help in bringing employees’ grievances to the attention of management and represent them in management meetings which affect employees.

1.6 PRODUCT PORTFOLIO Technology Centre manufactures a comprehensive range of products and offer a wide range of training services. Its product range is mainly based on the jobbing system (a product is manufactured according to the customer’s requirements).

Institools products include Drive Shafts, Pinion Shafts, Mould Plates, Press Tools, and Studs.

Instifoods products include Soy-yoghurt, Soy-milk, Soy-sour milk, Ice cream and Mineral water.

Institronics is involved in fabrication of printed circuit boards; it also has the responsibility of maintaining equipment in all the departments.

Full commercialisation is underway as the research and development work has now been completed. To date the three holding companies mentioned above are operating.

1.7 MARKET SUMMARY The introduction of the Buy Zimbabwe by Government favours the establishment of Institech holdings. Buy Zimbabwe is a campaign which encourages buying and selling as well as consumption of locally produced products.The indigenisation and empowerment act of 2007 also supports the company. Institronics other than its students providing the market, there are companies like Mukonitronics, Nations Hardware, Tendo Electronics, Advance Power and some SMEs who do business with them. The main challenge in production is, the economy remains constrained by lack of capital for retooling and working capital which has resulted in industry capacity utilization declining.Another challenge being faced by Institronics is the acquisition of raw materials since most of them are imported. This has resulted in out sourcing other services like negative production.

1.8 CONCLUSION Chapter one gave an overview of the Technology Centre, its background, ownership, vision and mission statements, management structure, product portfolio and some factors that have positive impact on Technology Centre.

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CHAPTER 2EXPECTATIONS AND INDUSTRIAL REALITY2.0. INTRODUCTION Having worked in the industry for more than twenty years, the student already had a knowledge of the realities of the industry, none the less he had expectations of his on since he was coming in as a University student undergoing a Degree training program. My expectations were as follows:

Having an appreciation of how businesses operate. Appreciation of organisational culture, policies, and processes through organisational understanding and sensitivity. Ability to understand basic financial and commercial principles.

The ability to identify, analyse and solve problems; work with information and handle a mass of diverse data, assess risk and draw conclusions.(Analysis, Attention to detail, Judgement)

The ability to work with others in a team and communicate, persuade and have interpersonal sensitivity.

The ability and desire to learn for oneself and improve awareness and performance. To be a self starter and to finish the job.

If managed the skills expected above and other qualities enhance an individual’s employability and confidence.

2.1. PERSONAL AND PROFESSIONAL DEVELOPMENT During the internship period the student had an opportunity to attend a train the trainer program on Occupational Safety and Health (OSH) offered by NSSA trainers. Everyone has a right to healthy and safe work environment that enables one to live a socially economically productive life. Topics covered included the following

Occupational Safety and Health Legislations in Zimbabwe - NSSA is the Authority responsible for the national planning, development and implementation of relevant programs in Occupational Safety and Health in Zimbabwe.

Safety Organisation in Zimbabwe - Safety organization falls into two main categories that is: As a government organization and Safety in the private sector.

Good Housekeeping - Good housekeeping involves every part of industrial operations and should apply throughout the entire premises, indoors and out. It is more than mere cleanliness.

Electrical Safety - Electricity has become an essential of modern life both at home and at the workplace. At the workplace some work with electricity directly and some indirectly. Electricity is essential to the operations of a modern automated office as a source of power. Electrical equipment used in an office is potentially hazardous and can cause serious shock and burn injuries if improperly used or maintained. As a source of power electricity has been accepted without much

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thought to the hazards encountered. Perhaps, because it has become such a familiar part of the surroundings, it often is not treated with the respect it deserves.

Hazard Identification, Classification and Control Measures - A hazard is a possible source to danger with a potential to cause harm to people, damage to property as well as the environment.

Role of Supervisor in Accident Prevention - Identify hazards, rectify or reports to management for corrective action and also Train workers on what precautions to take to prevent accidents/diseases.

Principles of Accident Prevention - Accidents cause disorganization, distress, disablement or sometimes death, they also damage machinery and equipment, spoil material and waste time resulting in lost man hours.

By definition an accident is an unplanned, uncontrolled event caused by an unsafe act or unsafe condition which may or may not result in an injury or damage to property. It can even result in a fatality.

2.2. KEY SKILLS DEVELOPMENT Time management is a process for understanding the way you use your time. The

keeping of an Internship Logbook taught me that the best time management technique is the use of a Time Management Plan. A plan provides organisation, and enables you to see what must be done and when. Many of us keep plans in our heads, but unfortunately, things are forgotten, or put off and simply not done. Since a Time Management Plan is written down, you can see where you have been and where you are going at a glance.

The student learned that you can improve your ability to solve problems and accomplish projects in three ways:

Develop learning and work relationships with people whose learning strengths and weaknesses are opposite to yours.

Practice and develop learning skills in your areas of weakness. Improve between your learning-style strengths and the kinds of learning and

problem-solving experiences you face. Hunger, Fatigue, and Distractions can be barriers to concentration. If you are hungry

do not expect to be able to sit down and work. However, you also cannot expect to be able to work after eating a large meal. You cannot concentrate for long when you are tired. The most common external distractions are noise and motion. Inner distractions differ from person to person and include thoughts and feelings that compete for your attention. You must identify your own distractions and create solutions to reduce them. Some of the ways to build concentration is to take responsibility for what you do and not to blame others for your mistakes and failures. This can be achieved by developing an interest in the project, setting a time for the completion of your task - this keeps you focused as you attempt to complete the work before time is up and relate what you learned with your project or assignment.

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2.3. PERSONAL DEVELOPMENT From the years of industrial experience the student has he reckons that his strength lies in his hand skills and knowledge of analogue electronics. This proved important in the projects the student carried out. The challenges the student faced are due to technological development in electronics were programming is playing a pivotal role. Though the student had studied Assembly and C-programming during the semester at college, programming proved to be very challenging. Through teamwork we managed to a certain extent, but are working on the code (program) to make improvements. In leading edge areas of technological development, there will, by definition, almost always be a skills deficit as education and training provision lags behind technological change. Fortunate enough for the student the education and training provisions were within the limits of the technological changes at HIT. The challenges in programming arose from the fact that they are new concepts the student has learned.

2.4 CONCLUSION In conclusion Chapter 2 has highlighted the student’s expectations, and how some of them have been accomplished. The chapter also highlighted the student’s strength and weaknesses and how the weaknesses were overcome. Skills development other personal developments are also explained.

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CHAPTER 3PROJECTS3.0 INTRODUCTION This chapter explains the various projects and work carried out by the student during the internship period. Training on Occupational Safety and Health (OSH) is not explained here since it was explained earlier in chapter 2.

3.1 PRINTED CIRCUIT BOARDS Printed Circuit Board (PCB) is the basic need in all electronic hardware. There are different types of PCBs such as single side, double side PTH, multilayer, PTFE, rigid and flex PCBs. PCBs are designed and manufactured depending on the end product. Some of the uses of PCBs are in the following equipments

Toys, Stabilizer, UPS, Inverters, TVs, Computers, Energy Meters, Power Electronics, Trainer Kits

Telecommunication Systems Medical Equipment Automotive Industrial Equipment Satellite Communication Systems Aeronautical Equipment

3.1.0 PLANT ORGANIZATION The plant is divided into six sections, it is located at HIT campus on stand number 1505 Ganges Road, Belvedere, Harare in the electronic workshop.

Pre-engineering section – the pre-engineering section is the starting point of PCB fabrication. The CAD (Computer Aided Design) section is where the schematic drawing, drill data and Gerber files are generated. The drill data is transferred to the CNC (Computer Numerical Control) for drilling. Gerber files are exported to the CAM (Computer Aided Manufacture) section for Photo Plotting.

Dark room – In the dark room the process of developing the negative or positive is done in photographic development manner.

Imaging room – the imaging room also known as the yellow room is where all imaging processes are carried out using UV (ultra-violet) light. Lamination is done in this room using a polyfilm which will act as etch resist when etching.

Wet process area – most of the chemical processes including copper and tin plating, etching and emission tin plating are done in this area. The processes involve moving the board from one chemical bath to another.

Mechanical section – before any process the copper clad boards are cut into smaller sizes with a small overlap and after processing the PCBs are cut to precise size in the mechanical section.

Waste process area – the wet process area uses chemicals which need to be disposed of, the waste process area is where the effluent is neutralized for safe disposal. Also

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1 2

16

15

14

9

7

8

4 3

13 12 11

10

6

5

in the waste process area is where de-ionized water is generated. De-ionized water is used to neutralize chemicals in the various chemical baths in the wet process area.

The figure below shows the plant layout.

Fig1

The area which makes up the Printed Circuit Board plant is the shaded one and some areas in between and will be explained. A key to the layout of the plant is shown below

1 – Toilets for both students and staff2 – Robotics room3 – Electronic Workshop Stores4 – Block of Offices for Lecturers5 – Central Stores for PCB Plant6 – Emission Tinning Room7 – Imaging Section8 – Pre-engineering Laboratory9 – Dark Room10 – Heat Chamber11 – General Stores12 – Technical Instructors Office13 – Lecture Room14 – Programmable Logic Control Laboratory15 – Departmental Chairman’s Office

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Waste Process Area

16 – Wash Room

The whole area to the right of the imaging section (7) including Emission Tinning room is the Wet Process Area. In front of the Central Stores for the PCB Plant (5) is the Mechanical Section.

3.1.1 MAINTENANCE Since the student started internship at the beginning of the year; the first task he got involved in was in routine maintenance of the printed circuit board plant. Plant maintenance result in reduced costs as this will reduce downtime. Equipment reliability is also improved.

Fig2

After maintenance of at least two machines the student was asked to supervise the maintenance of the remaining machines with a team of three. Maintenance involved cleaning the equipment, degreasing and greasing, changing oils in accordance to the various equipment service manuals, refilling all chemical baths and test running of the equipment. At the end of the maintenance schedule a report on equipment status was complied for onward transmission to management. From time to time repair work was done to equipment in both the Tool and Die Workshop and the PCB plant.

A) SCRUBBING MACHINE – Brushing/Scrubbing/Cleaning operations play an important role in Printed Circuit Board manufacturing. Brushing/Scrubbing will be done before Electro-less Plating/Direct Plating, Surface Treatment before Solder masking and Dry film Lamination. Maintenance of the Scrubbing machine is done daily, weekly and monthly.

Daily maintenance: 1) Wipe the surface of Machine and remove all dirt. 2) Clean out the copper powder, tin powder and other dirt in the machine. 3) Check brush, backup roller, pinch roller and conveying roller to see if they are stained. Use hot water or cleaning powder to clean the dirt. 4) Inspect nozzles to see if they are clogged – to clean clogging stuff use air-compressed gun to aim and shoot at the water in let of the nozzle.

Weekly maintenance: 1) Check brush level-use level adjustment wheel to adjust until it meets the requirement.

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PLANT MAINTENANCE SUPPORT

EQUIPMENT RELIABILITY

REDUCED COSTS

2) Check if the surface of backup roller is level and smooth. 3) Put grease on transmission gear, chain, brush bearing and oscillating structure for lubrication purpose.

Monthly maintenance: 1) Check all running parts to see if they are worn-out, eroded and loose. If, so adjust or replace them.

The Scrubbing Machine has a Control Panel to control and monitor its operation. The Control Panel is based on Industrial panel design made out of MS sheets neatly powder coated to international finish. It is a stand type with push buttons and indicators mounted on the top panel for easy vision and operation. The top panel is White PVC neatly engraved with all the function markings. The Control Panel comprises of the following:

Push Buttons Emergency Switches AC Inverter Temperature Controllers MCCB Alarm Flasher Relays Contactors Switches ON/OFF Low level indicators Speed Indicator (Conveyor) Speed Controller (Conveyor) Cooling Indicators

The Control Panel is connected to the machinery by Electrical cables through conduit pipes. All the Electrical wiring of the individual motors and heaters etc, is concealed neatly in PVC pipes. A picture of the Control Panel is show in Appendix 1.

B) Conveyorised Developing Machine – The conveyor system is a simple shaft driven Bevel Gear System. The system consists of a main drive shaft of Dia slot, which is driven through a chain sprocket system by a ELTEK AC Geared Motor. The speed of the conveyor is controlled by 1HP AC Frequency Inverter mounted in the control panel and displayed on a digital meter.Maintenance of the machine is explained below:

Clean the outside of the machine everyday to remove stains, sludge and crystallized chemicals.

Every week thoroughly clean the conveyor driveshaft and gears to remove crystallized chemicals and sludge, which will give a smooth finish and allow conveyor to move without any problem. – Thoroughly rinse the area with clean water and dry with high pressure air.

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Monthly inspect all moving parts for wear, corrosion, looseness etc and replace worn-out parts for smooth functioning of the machine.

Most of the PCB machines are conveyorised, thus the maintenance procedure for all these machines is the same, and this is observed from the two machines explained above. The other machines are not explained and also electrical drawings are show for the Scrubbing Machine only.

3.2 SOLAR DRIER

3.2.0 INTRODUCTION Fruits and vegetables with their rich contents of minerals, vitamins, and dietary fibre and anti oxidants are the protective foods and considered as nature gifts for health and well being of humans. They are highly perishable in nature due to high moisture content (70-95%); soft texture etc bacterial rotting by microbial respiration as well as physiological breakdown is seen. In most cases moisture degradation in the quality of fruits and vegetables also starts immediately after the harvest leading to drying and shrivelling. Fruits and vegetables absorb environment gasses such as oxygen and produce carbon dioxide and ethylene. They also get infested easily with micro organisms like fungi, bacteria and insects affecting food safety. In villages where fruits and vegetables are grown in plenty, facilities for processing are not in existence and lots of them are wasted. In the country the whole food processing industry still has not grown big and presently a little of horticultural produce is being processed industrially by canning. Hence these fruits and vegetables are to be preserved and protected from deterioration in both quality and quantity.

3.2.1 SUN DRYINGFood drying is a very simple, ancient skill. It is one of the most accessible and hence the most widespread processing technology. Sun drying of fruits and vegetables is still practised largely unchanged from ancient times. Traditional sun drying takes place by storing the product under direct sunlight. The main advantages of sun drying are low capital and operating costs and the fact that little expertise is required.The main disadvantages of this method are as follows:

Contamination theft or damage by birds, rats or insects slow or intermittent drying no protection from rain or dew that wets the product, encourages mould growth may result in a relatively high final moisture content low and variable quality of products due to over- or under-drying large areas of land is needed for the shallow layers of food it is laborious since the crop must be turned, moved if it rains direct exposure to sunlight reduces the quality (colour and vitamin content) of some

fruits and vegetables.Moreover, since sun drying depends on uncontrolled factors, production of uniform and standard products is not expected.

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The quality of sun dried foods can be improved by reducing the size of pieces to achieve faster drying and by drying on raised platforms, covered with cloth or netting to protect against insects and animals.

3.2.2 SOLAR DRYINGDue to the current trends towards higher cost of fossil fuels and uncertainty regarding future cost and availability, use of solar energy in food processing will probably increase and become more economically feasible in the near future.Solar dryers have some advantages over sun drying when correctly designed.

They give faster drying rates by heating the air to 10-30°C above ambient, which causes the air to move faster through the dryer, reduces its humidity and deters insects.

Fast drying reduces the risk of spoilage, improves quality of the product and gives a higher throughput, so reducing the drying area that is needed. However care is needed when drying fruits to prevent too rapid drying, which will prevent complete drying and would result in case hardening and subsequent mould growth.

Solar dryers also protect foods form dust, insects, birds and animals. They can be constructed from locally available materials at a relatively low capital

cost and there are no fuel costs. Solar dryers can be useful in areas where fuel or electricity are expensive, land for sun drying is in short supply or expensive, sunshine is plentiful but the air humidity is high. Moreover, they may be useful as a means of heating air for artificial dryers to reduce fuel costs [1]Solar food drying can be used in most areas but how quickly the food dries is affected by many variables, especially the amount of sunlight and relative humidity. Typical drying times in solar dryers range from 1 to 3 days depending on sun, air movement, humidity and the type of food to be dried.

The principle that lies behind the design of solar dryers is as follows: in drying relative and absolute humidity are of great importance. Air can take up moisture, but only up to a limit. This limit is the absolute (maximum) humidity, and it is temperature dependent.

When air passes over a moist food it will take up moisture until it is virtually fully saturated, that is until absolute humidity has been reached. But, the capacity of the air for taking up this moisture is dependent on its temperature.

The higher the temperature, the higher the absolute humidity, and the larger the uptake of moisture.

If air is warmed, the amount of moisture in it remains the same, but the relative humidity falls; and the air is therefore enabled to take up more moisture from its surrounding.

3.2.3 TYPES OF SOLAR DRYERSThere are mainly three types of solar dryers (3): 1. The absorption or hot box type dryers in which the product is directly heated by the sun, 2. The indirect or convection dryers in which the product is exposed to warm air which is heated by means of a solar absorber, or heat exchanger,

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3. Dryers combining the principles of the above two, where the product is exposed to the sun and a stream of pre-heated air simultaneously.This project seeks to implement Solar Dryer number 2(Convection Dryer).

3.2.4 DESCRIPTION OF THE SOLAR DRYER The Solar Drier comprises of:-

A drying chamber – the chamber is made of aluminium metal and has shelves inside for drying trays.

Solar panel – sense there are fans for air circulation which require electrical energy the solar panel is used for energy conversion from solar to electrical.

Inverter – the fans used are 220V AC thus the need of an inverter to convert DC to AC.

Battery – the energy from the solar panel is stored in the battery. Charge controller – since the brighter the sunlight, the more voltage the solar cells

produce, the excessive voltage could damage the battery. A charge controller is used to maintain the proper charging voltage on the batteries. As the input voltage from the solar panel rises, the charge controller regulates the charge to the batteries preventing any overcharging.

PID temperature controller – To accurately control process temperature without extensive operator involvement, a temperature control system relies upon a controller, which accepts a temperature sensor such as a thermocouple or RTD as input. It compares the actual temperature to the desired control temperature, or setpoint, and provides an output to a control element. The control is algorithm so a PID controller was chosen. This controller type provides proportional with integral and derivative control, or PID. This controller combines proportional control with two additional adjustments, which helps the unit automatically compensate for changes in the system.

Air inlet system – is covered with glass to allow the sun to heat the collected air.

The first picture in Appendix 2 shows the air inlet and the solar panel. The second one shows the PID temperature controller and the charge controller used in this project, while the third is the PID interconnection. The task we had was to connect the modules together to work as a unit. In the picture below the wires are not in the conduits because this was a trial run after successful run the wiring was redone and wires put in conduits.

3.2.5 CONCLUSION The drier project was a success. Results of the drier where obtained and verified by those in the Food Processing Technology department;

3.3 EGG INCUBATOR Poultry egg incubation plays an important role in the overall poultry production system especially during the day old chick development. Poultry production is a lucrative business but lack of commercially owned hatchery machines hinder the expansion and make poultry products for instance day old chicks costly. Presently, few commercially owned poultry hatcheries in Zimbabwe are located in major cities which are far away from the farmers. People in the rural area have to travel long distance to buy day old chicks. They have to make bookings and return some other day to collect the chicks this makes the process costly and cumbersome. This project seeks to design smaller egg incubator that can be distributed to small holder farmers. With rural electrification program majority of small holder farmers can

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boost poultry farming from this project if successful. The system consists of three basic compartments: a power supply unit, a control unit and the egg incubation chamber. The incubator is capable of handling up to 1080 eggs per batch of incubation. Experiments on requirements for successful hatcheries indicate temperature and relative humidity range of between 36– 39°C and 50 – 70% respectively. Further biological test using fertilized poultry eggs showed 74% efficiency of the incubator if maintained within the limits.

3.3.0 INTRODUCTION Poultry egg incubation is an activity that requires sustainable energy supply for efficient performance, operation and profitability. This involves the management of fertilized poultry eggs to a satisfactory development level that leads to normal chicks [2]. It includes the control of the extrinsic environmental factors of the surrounding. Naturally, a mother hen performs this function but at low efficiency [3]. And artificially, an incubator, a special system that simulates the environmental conditions required for such operation is usually employed by poultry farmers to do the same operation within specified temperature and relative humidity range. The ranges are usually between temperature and relative humidity of between 36 – 39°C and 50 – 70% respectively. To maintain this temperature range sustained heat supply is paramount. In the most developing countries, the vast majority of poultry farmers in the rural communities operate their farms on small scale and/or even subsistence level. They often use a collection of bush lamps and kerosene stoves to achieve the heating requirements of the small hatcheries and brooders for day-old chicks [4]. In Zimbabwe they buy from commercial farmers or leave it for the mother hen (brooder) to do the job. The problems with these systems are enormous ranging from environmental pollution and fire outbreak. Use of fossil fuel is known to produce toxic gases which are harmful to eggs and poultry attendants. Electricity based egg incubators are known to produce clean energy without harmful effects on the environs but they are however limited in operation due to the initial cost of procuring such equipment coupled with the high cost of electricity, frequent power outages where grid electric exists and the unavailability especially in the rural areas. In Zimbabwe the government embarked on a program of rural electrification.

3.3.1 DESCRIPTION OF THE EGG INCUBATOR The egg incubator is made of three namely the egg incubation chamber, control unit and the power supply units.

The egg incubation chamber consists of five egg trays with dimensions 0.4m x 0.53m and a relative humidity pan. The chamber is capable of handling about 1080 poultry eggs with each tray housing 90 eggs per batch. The entire body of the incubator is constructed with 2cm thickness wood. The egg trays connected to an external motor with a lever system that can turn the trays at 45°. The turning mechanism is to avoid egg yolk sticking on the egg shell.

The power supplies convert high voltage AC mains electricity to a suitable low

voltage supply for electronic circuits and other devices. A power supply can by broken down into a series of blocks, each of which performs a particular function.

220V Regulated

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Transformer

Rectifier

Smoothing

Regulator

AC Output Voltage Mains

Fig3

Transformer - steps down high voltage AC mains to low voltage AC. Rectifier - converts AC to DC, but the DC output is varying. Smoothing - smoothes the DC from varying greatly to a small ripple. Regulator - eliminates ripple by setting DC output to a fixed voltage.

The regulated 5V DC supply is drawn together with the control unit. Below is the 12V DC supply circuit and track layout diagram. The 12V supply is used for interfacing the control unit to the motor, heater and humidifier.

Fig4

The egg incubator is controlled by a microcontroller pic16F877A. Microcontrollers are general purpose microprocessors which have additional parts that allow them to control external devices. PIC16F877A was chosen for this system because it is cheap, accepts analogue input since it has an internal ADC circuit. It has enough input/output pins some being reserved for future use. Pin diagram is shown below.

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Fig5

3.3.2 SYSTEM BLOCK DIAGRAM

Fig6

Temperature Sensor –LM35 is a precision integrated-circuit temperature sensor, whose output voltage is linearly proportional to the Celsius temperature. The LM35 thus has an advantage over linear temperature sensors calibrated in °Kelvin, as the user is not required to subtract a large constant voltage from its output to obtain convenient Celsius scaling. The LM35’s low output impedance, linear output, and precise inherent calibration make interfacing to readout or control circuitry easy. It has very low self-heating, less than 0.1°C in still air. The LM35 is rated to operate over a −55°C to +150°C temperature range. Its scale factor is linear +10mV/°C.

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Microcontroller

Temperature sensor

Humidity sensor

Micro switches

4x3 keypad

16x2 LCD

Relays

Motor

Humidifier

Heaters

Fan

4 LEDS

Humidity Sensor –Humidity sensor should provide humidity level in the incubator in terms of relative humidity (%RH) in the range of 0-100%RH. The Humidity Sensor chosen for the present work is CA4H02522A. The humidity sensor is chosen on basis of accuracy, linearity, and low power design, workable within required temperature range, repeatability and stability. The specifications fulfils the requirement that is required for the measurement of relative humidity in egg incubator hence capacitive type relative humidity sensor was used in comparison to other humidity sensors.

Micro-switches – Micro-switches are a good type of switch to use for making touch sensors. A micro-switch is housed in a rectangular body and has a very small button (switch nub) which is the external switching point. A lever arm on the switch reduces the force needed to actuate the switch. In this project two micro switches are used to limit the angle of tilting the egg tray to -45° and +45°.

4x3-keypad – A keypad is just a set of push-buttons connected in such a way to form 'rows' and 'columns', thus reducing a number of input/output pins necessary for their connection. A keypad with 12 push-buttons arranged in 4 rows and 3 columns is used in this example. The keypad is used to enter the set values for both temperature and humidity. To simplify the project for the keypad is initially omitted the set value is preset in the code.

16x2 LCD – 16x2 LCDs are most commonly used display units in microcontroller based projects. These displays can be driven either in 4-bit or 8-bit mode. In the first case only the high nibble (D4 to D7) of the display’s data bus is used. In this project the LCD is driven in 4-bit mode to display both temperature and humidity.

Relays – A relay is an electrical switch that opens and closes under the control of another electrical circuit. It is therefore connected to output pins of the microcontroller and used to turn on/off power devices such as motors, fan, heaters, humidifier, etc. These devices are almost always placed away from the on-board sensitive components.

Motor – To rotate the eggs through 90° a fan motor is used, connected in a way that it becomes bidirectional.

Heater – The heating element was the freezer type element. Humidifier – Due to unavailability of humidifiers and to reduce cost a tray of water is

used. Fan – A 220V AC fan is used to circulate both heat and humidity for even distribution

in the chamber. LEDs – Three LEDs are used to indicate the state in which the chamber is.

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The schematic diagram is below

Fig7

3.3.3 DESIGN REQUIREMENTS OF THE SYSTEMDesign Requirements of the System

3.3.4 SOFTWARE DESIGN

The code for the control system was written in C-language. This proved challenging, especially to incorporate the micro-switches. The flow chart for the program is shown below, while the code is in appendix 3

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Mode of System Operation Automatic Control

Temperature Range 36°C - 39°C or User requirements

Relative Humidity

Mode of input of parameters

50% - 70 % R.H or User Requirements

User Friendly

Temperature of water reservoir 42 °C - 45 °C

Mode of Temperature Control Chamber -Temperature Control

Display LCD

PROGRAM FLOW DIAGRAM

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start

Initialize all

Read temperature from sensor

Display temperature

Lower limit >= read temp

Turn ON heater and circulating fan

Upper limit <= read temp

Turn OFF heater and circulating fan

B

A

3.4 CONCLUSION In this chapter the student highlighted the projects which he was involved in, in detail.

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B

Read humidity from sensor

Display relative humidity

Lower limit >= sensor RH

Upper limit <= sensor RH

Turn ON humidifier

Turn OFF humidifier

A

CHAPTER 4CONCULSION AND RECOMENDATION

4.0 CONCULSION The objectives for an internship as highlighted in Chapter 1; to bring professional experience to students in electronics science and technology and related areas of engineering; as well as to improve their engineering skills by means of observing technological developments and applications in professional areas, providing them with hands on training sessions within production environments and research laboratories in the organizations. When students have good engineering skills and hands on experience they become employable, making sure that they do not become redundant on completion of their degree programs. Industrial internship is a good program to give students hands on experience and practical knowledge or insight to how industry works. Every industry has its own politics, internship programs prepare students to raise to the occasion when they finally get into industry.The student’s expectations were met with not much highlights. There was however one instance when industrial realities showed its ugly face. On the projects the student was involved in, the way they were introduced to the project seemed not professional. The electronics team was told to make control circuits pronto-pronto when all chambers had been constructed living them with little lee-way to mark adjustments to the chambers to suite wiring and housing of control board.

4.1 RECOMMENDATION A proper internship program needs to be established at Harare Institute of Technology so that internship students get tasks and projects on time. When the organization is embarking on new projects all departments involved should meet before any design starts so as to align all the necessary units. As the project is being done consultations and updates should done frequently so that people remain with one goal.

The student enjoyed the internship at HIT, it was a success. Once again thank you all.

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REFERENCES

[1] Fellows, P. Guidelines for Small-Scale Fruit and Vegetable Processors, FAO AgriculturalServices Bulletin 127, FAO of the United Nations, Rome, 1997.

[2] J. A Oluyemi and F. A. Roberts. Poultry Production in Warm Climates. The Macmillan Publishers Limited, London and Basingstoke. 1979.

[3] N. A. French. Modeling Incubation Temperature: The Effect of Incubator Design, Embryonic Development, and Egg Size. Poult. Sci. 1997, 76:124–133.

[3] W. I. Okonkwo. Design of solar Energy Egg Incubator. Unplished undergraduate project, Department of Agricultural Engineering, University of Agriculture, Makurdi, Nigeria. 1989.

[4] Dogan Ibrahim. PIC BASIC Projects. Linacre House, Jordan Hill, Oxford OX2 8DP, UK. 2006.

[5] Poul Klausen. Introduction to programming and the C# Language. Bookboon.com (Ventus Publishing ApS). 2012

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APPENDICES

APPENDIX 1

Control Panel of the Scrubbing Machine

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APPENDIX 2

Solar Dryer

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Charger Controller

Wiring of the PID temperature controller

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APPENDIX 3

C-code for the egg incubator control system.

#include <16F877A.h> #device adc=8 #FUSES NOWDT //No Watch Dog Timer //#FUSES HS //Highspeed Osc > 4mhz //#FUSES PUT //Power Up Timer #FUSES NOPROTECT //Code not protected from reading #FUSES NODEBUG //No Debug mode for ICD #FUSES NOBROWNOUT //No brownout reset #FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O #FUSES NOCPD //No EE protection #use delay(clock=4000000) //crystal oscillator at 4000000 hertz #use rs232(baud=9600, xmit=PIN_C6, invert) //serial port output pin & baud rate #include "flex_lcd.c"

void motor() { int a, b, c; a = input(PIN_C1); // auto mode switch b = input(PIN_D4); // forward limit switch c = input(PIN_D5); // reverse limit switch

if (a==0) // if 'a' (auto mode switch) is on

{

if (b==0) // the programme then tests the limit switches 'b' and 'c'

{

output_low(PIN_D2);

delay_ms(1000);

output_high(PIN_D3);

delay_ms(1000);

}

else if (c==0)

{

output_low(PIN_D3);

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delay_ms(1000);

output_high(PIN_D2);

delay_ms(1000);

}

}

else

{

output_low(PIN_D2);

output_low(PIN_D3);

//delay_ms(2000);

}

// break;

}

void main ()

{

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// int i,x=15;

int temp_adc, humi_adc;

float temp,humi;

lcd_init();

setup_adc(ADC_CLOCK_INTERNAL); //configure analog to digiral converter

setup_adc_ports(ALL_ANALOG);

// lcd_init();

printf(lcd_putc,"\f");

while (true)

{

motor();

temp_adc=read_adc();

// temp = ((temp_adc/1023)*500);

temp= temp_adc/0.48875855327468230694037145650049;

// temp =( 5 * temp_adc *100 )/1023;

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// humi_adc=read_adc();

// humi= humi_adc/0.52343134;

// lcd_putc("\f");

if (temp >= 39)

{

// lcd_putc("\f");

output_high(PIN_D0);

output_low(PIN_D1);

lcd_gotoxy(1,1);

printf(lcd_putc,"Temp:%f C",temp);

delay_ms(1000);

}

else if (temp <= 36)

{

//lcd_putc("\f");

output_low(PIN_D0);

output_high(PIN_D1);

lcd_gotoxy(1,1);

printf(lcd_putc,"Temp:%f %cC ",temp %c);

delay_ms(1000);

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}

else

{

// lcd_putc("\f");

output_low(PIN_D0);

output_low(PIN_D1);

// output_high(PIN_D2);

// output_high(PIN_D3);

lcd_gotoxy(1,1);

printf(lcd_putc,"Temp=%f C\n",temp);

lcd_gotoxy(1,2);

// printf(lcd_putc,"Temperature ok");

delay_ms(1000);

}

}

}

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