1.1 Demand in buying items needed 24 hours a day

Shops are placed for people to go and buy something that they need. Unfortunately, they cannot go there at night as the premises will definitely close. So, how can we solve this problem? What people might think is we can have a 24 hours shop in order to solve the problem. Yes, by having 24 hours shop, we can solve this problem but we need to think about other factors that might raised as a result of having 24 hours shop like the electricity usage factor, labour factor, security at night factor and many other factors associate with that. One of the solutions of replacing a 24 hours shop is by implementing a vending machine.

What is vending machine?

A vending machine is a machine that dispenses product when a customer deposits a sufficient amount of money into a money slot. The money is accepted by a currency validator. It is a machine that provides various snacks, drinks and other products to customers.

Why we need vending machine?

The idea of having vending machine is to vend product without a cashier.

For instance, Japan is one of the countries that use many vending machines. So, we can easily found vending machines all over the cities, towns and even in the countryside. Even, you can buy rice from vending machine! It is said that almost none of them are vandalised, meaning that people there are really appreciate this technology.


Picture 1. Vending machine that sells various kinds of rice.


Picture 2. Vending machine that sells eggs from farm.


Picture 3. Vending machines that sell foods and drinks.

What do we get by having vending machine?

By having vending machines, we found that labour cost can be reduced. For instance, by referring to Picture 3, we can see that many vending machines are installed in the restaurant. People still can buy their food and drinks, eat in the restaurant and clean the table themselves after they finish having their meal, but the difference is that they buy their food from the machines.

Second, by having vending machines, we are able to buy the things that we need at anytime as it does not require us to go and buy from the shop. For instance, by referring to Picture 1 and Picture 2, we found that we can even buy rice and eggs from the vending machines. So, if you feel hungry at night and suddenly you realised that your rice or your eggs has finished, you do not need to worry as you can easily buy them from the vending machines. This proof that vending machines give a lot of benefits to us and that is why Japanese really appreciate this technology.

Third, by having vending machines that can sell almost everything, we found that we are able to reduce space. What we mean is instead of erecting new shop which definitely requires lots of space; we can replace them by allocating the vending machines.

1.2 Vending machines require power

However, this technology also requires power. So, it can be said that this machines contribute to increment the power usage, which this not sounds good for our earth as high power usage will contribute to global warming.

According to an article entitled “production and consumption of nuclear energy” that can be found from this URL, http://www.planete-energies.com/content/nuclear-energy/production-consumption.html, it says that up to year of 2006, the amount of electricity generation from nuclear energy throughout the world is 2,660 GKWh. The fraction of it can be viewed from the Table 1 below.


Table 1. World electricity generation from nuclear energy by country (2006) and the share of nuclear energy in total electricity generation

According to an article that can be found from the URL, http://www.absenergyresearch.com/cmsfiles/reports/Hydro-Power-Report-Ed-2-2009.pdf, it says that hydropower which also contributes in generating power, has increased from under 50GW in 1950 to an estimated 929GW in 2008.

We could also look at Picture 4 which shows the rate of world energy usage (in Terawatts) which can be found from this URL, http://en.wikipedia.org/wiki/World_energy_resources_and_consumption.


Picture 4. Rate of world energy usage in Terawatts from 1965 to 2005.

This shows that, people are using too much power nowadays. Again, how can we solve this problem?

1.3 Solar cell takes place

People now have start thinking of finding alternative energy sources as to avoid an extreme serious energy shortage in the future. Solar power can play a role as an alternative energy source.

What is solar cell?

Solar cell is a panel which convert sunlight into DC electricity without moving any parts, noise pollution and even radiation.


Picture 5. Solar panel

Lots of people are using solar cell in their daily living as an alternative method to reduce the power usage from mains i.e. solar cell water heater and solar cell hand phone battery charger. There are several reasons why you will think that solar cell is a perfect solution,

1. You will save most of your money every time you get your power bill
2. You will save the environment and your children will thank you for it
3. You will know that you are doing your part to protect our planet
4. You are able to spend your savings on more important things

Hence, it is a good idea to combine the solar feature into a vending machine as it would reduce more problems coming from domestic power usage. Even we can found many equipment that uses solar power nowadays. For instance, we can find one section called Greenshop at Dixons webpage where it is a section of selling energy saving products. This URL shows solar-powered radio is been sold by Dixons (http://www.dixons.co.uk/martprd/store/dix_page.jsp?BV_SessionID=@@@@1343874277.1238110843@@@@&BV_EngineID=cccfadegldkkfhdcflgceggdhhmdfho.0&chain=Dixons&int=hp-greenshop&channel=WEB&page=GenericEditorial&genericeditorial=Greenshop-home).

1.4 Solar-powered vending machine comes into real life

What is solar-powered vending machine?

Solar-powered vending machine is a vending machine that powers its vending and refrigeration mechanisms with solar power. It is equipped with a battery that able to stores energy which sufficient enough for the machine to use it back whenever it does not receives any sunlight (at night or cloudy day).

Why we need solar-powered vending machine?

These are some benefits of having solar-powered vending machine,
1. To reduce the energy usage which comes from the mains (plant)
2. To vend a product without a cashier
3. To sell various products in 1 place (in one vending machine)
4. To save space (vending machine does not require lots of space compared with ordinary shop)
5. To buy items wanted anytime (day and night)

Apart from that, by using solar power, implicitly we can have another benefit which is this machine can be put anywhere! (Mobility feature is added).

What do we mean by mobility?

Mobility means the ability to move freely. We called this machine a mobile machine because we can put this machine at any place that able to receive sunlight. Hence, this machine will no longer be stagnant in one place.

Where are the possible places to place this machine?

As mentioned earlier, we can put this machine anywhere as long as it able to receive sunlight. Below is the list of possible places that we think it might be useful to put the machine,
1. Beach
2. Golf course
3. Highway
4. Places of interest (garden, park, lake, etc.)
5. Outside the campus building
6. Desert

Actually, there are many other places that we can put this machine. For instance, if you are studying in a big university like Nottingham University, it might be tired for you to walk from your resident hall to your campus. By placing the machine somewhere in your route to the campus, you can easily purchase any drinks desired to quench your thirst whenever you feel thirsty or tired.

Beach is the most suitable place that we might think of putting this machine at because people will definitely buy some drinks or snacks after spending couple of hours playing beach volleyball, surfing or even swimming. It is convenient to have this machine close to the beach as people will easily go and buy the items wanted rather than place it far from the beach.

If we look at the Asian Middle East country, almost every part of the countries is covers with dessert. It is difficult to get electricity source directly from the mains. So, that is why this machine is perfect for them as the problem of having difficulties to get electricity source can be eliminate. Furthermore, Asian countries have no problem to receive enough sunlight as it situated at a portion of the world that able to receive enough sunlight every day.

Who can use this machine?

Almost everyone in this world can use this machine as this machine can be put anywhere as long as it receives sunlight.


Picture 6. Solar-powered vending machine at beach


Picture 7. Solar-powered vending machine at park



The objective of this project is:

1. To utilize the skills and knowledge that we have gained during our studies
2. To work independently with minimum supervision
3. To produce a project within a time frame given
4. To produce a spirit of team working
5. To build a good communication within the group member and with other people such as vendor, department, management as well
6. To furnish with experience, knowledge and skills throughout the process involves in producing this project
7. To gain experience in problem solving that we might be faced in future
8. To be creative and innovative

Besides knowing the purposes of making a project, we must also have the objectives of why the product needs to be construct, which is:

1. To construct a vending machine which powered by solar cell instead of normal power obtained from power socket
2. To construct an automated machine that can vend a product to customer 24 hours a day
3. To design a vending machine that can be placed anywhere (outside the building)
4. To develop a vending machine that able to give you the results of what you need to know on the spot (real time observation) by using SMS (i.e. able to send an SMS to the appropriate person when the product running empty, when the machine is been moved by unauthorized person etc.)



Machine name : Solar powered vending machine

Monitoring : Personal computer, Mobile phone

Other features : Alarm system

Power supply (source) : 240VAC solar power

Power supply unit : 12VDC (robotic arm), 12VDC to 30VDC (compressor), 10VDC to 30VDC (diffuse sensor), 12VDC (notes/coins validator), 12VDC (LCD touch screen), 2.7VDC to 2.8VDC (GSM Modem)

Machine dimension : 190cm X 100cm x 100cm (HxWxD)

Weight : 100kg (nett empty)

Operating mode : Automatic

Transfer system : Robotic arm (pick and place)

Drive system : Servo motor (included in robotic arm), stepper motor (output tray)

Type of Control Panel : Touch screen

System : Visual Basic 6.0, Logiccode GSM ActiveX (SMS)

Sensor : Limit switch, mercury switch, optical sensor (diffuse type)

4.0 SAFETY FEATURES

Safety features are needed as a protection for this proposed project as to make sure that this machine will be operated smoothly. Here are some of the safety features found in this proposed project:

1. Insulation System

• To keep all cables and devices well insulated as to maintain its longevity and effectiveness
• To prevent the devices from short-circuit

2. Relay

• To protect from any excessive current

3. Circuit Breakers (MCB & ELCB)

• To protect an electrical circuit from damage caused by overload or short circuit

4. Antivirus Software

• To protect the computer from viruses that may harm the implemented program

5. Security System

• To provide password protection at the system (VB) so that only authorized person is able to conduct the test
• To make sure that only authorized person is able to accept and send SMS

5.1 Layout Diagram - Front view

5.2 Layout Diagram - Assembly drawing

6.1 System Overview

6.2 How Does the Machine Works

During the day time i.e. with sufficient sunlight, the vending machine will operate using the solar power. At the same time, the battery will be also recharged with the energy gained from the solar cell as well as powering the machine. When the sun goes down or when the available light is not sufficient to generate electrical energy, the machine will operate using the battery power which is stored before. Basically, the machine has 2 power sources that can be used alternately during the day and night. The battery should be able to supply power to operate the machine for at least 5 days consecutively without sufficient sunlight in worst-case-scenario.

The user interface (control panel) is activated all the time as the machine operates. It works just like other vending machine i.e. displaying products’ price, providing items selection for users, accepting the payment and dispensing the items, but with the weatherproof features. The operation of product dispensing is controlled by the control unit which consists of microcontroller circuit, DC motors, sensors and robotic arms.

The machine is also equipped with product counter and a unique system to alert the responsible person (supplier) whenever the machine is almost empty or the money storage is almost full, so that he/she could refill the machine, reset the counter and clears the money. The system consists of a simple short-message-service (SMS) transmitter to automatically send an alert message to supplier when the stated conditions happen.

As for security features, the anti-theft system operate all the time in order to ensure the machine is always secured. If any attempt of vandalism or theft happens, security alarm will be activated to alert everyone nearby and at the same time an emergency message (SMS) will be sent to responsible persons (supplier/security) for further actions. The system consists of sensors such as mercury switches and limit switches to trigger the alarm due to aggressive vibrations and displacements. Once activated, the alarm only can be disabled by authorized person by keying in a secret code via the user interface.

6.3 How Does Solar Cell Works

We have probably seen calculators that have solar cells, calculators that never need batteries, and in some cases don't even have an off button. As long as we have enough light, they seem to work forever. We may have seen larger solar panels on emergency road signs or call boxes, on buoys, even in parking lots to power lights.

Although these larger panels aren't as common as solar powered calculators, they're out there and not that hard to spot if you know where to look. There are solar cell arrays on satellites, where they are used to power the electrical systems.

On a bright, sunny day, the sun shines approximately 1,000 watts of energy per square meter of the planet's surface, and if we could collect all of that energy we could easily power our homes and offices for free.

The solar cells that we see on calculators and satellites are photovoltaic cells or modules (modules are simply a group of cells electrically connected and packaged in one frame).

Photovoltaic’s, as the word implies (photo = light, voltaic = electricity), convert sunlight directly into electricity. Once used almost exclusively in space, photovoltaic are used more and more in less exotic ways. They could even power your house.

Photovoltaic (PV) cells are made of special materials called semiconductors such as silicon, which is currently the most commonly used. Basically, when light strikes the cell, a certain portion of it is absorbed within the semiconductor material. This means that the energy of the absorbed light is transferred to the semiconductor. The energy knocks electrons loose, allowing them to flow freely. PV cells also all have one or more electric fields that act to force electrons freed by light absorption to flow in a certain direction. This flow of electrons i¬s a current, and by placing metal contacts on the top and bottom of the PV cell, we can draw that current off to use externally. For example, the current can power a calculator. This current, together with the cell's voltage (which is a result of its built-in electric field or fields), defines the power (or wattage) that the solar cell can produce.

6.4 How Silicon Makes a Solar Cell

Silicon has some special chemical properties, especially in its crystalline form. An atom of silicon has 14 electrons, arranged in three different shells. The first two shells, those closest to the centre, are completely full. The outer shell, however, is only half full, having only four electrons. A silicon atom will always look for ways to fill up its last shell (which would like to have eight electrons). To do this, it will share electrons with four of its neighbour silicon atoms. It's like every atom holds hands with its neighbours, except that in this case, each atom has four hands joined to four neighbours. That's what forms the crystalline structure, and that structure turns out to be important to this type of PV cell.

Pure silicon is a poor conductor of electricity because none of its electrons are free to move about, as electrons are in good conductors such as copper. Instead, the electrons are all locked in the crystalline structure. The silicon in a solar cell is modified slightly so that it will work as a solar cell.

A solar cell has silicon with impurities, other atoms mixed in with the silicon atoms, changing the way things work a bit. We usually think of impurities as something undesirable, but in this case, the cell wouldn't work without them. These impurities are actually put there on purpose. Consider silicon with an atom of phosphorous here and there, maybe one for every million silicon atoms. Phosphorous has five electrons in its outer shell, not four. It still bonds with its silicon neighbour atoms, but in a sense, the phosphorous has one electron that doesn't have anyone to hold hands with. It doesn't form part of a bond, but there is a positive proton in the phosphorous nucleus holding it in place.

When energy is added to pure silicon, for example in the form of heat, it can cause a few electrons to break free of their bonds and leave their atoms. A hole is left behind in each case. These electrons then wander randomly around the crystalline lattice looking for another hole to fall into. These electrons are called free carriers, and can carry electrical current. There are so few of them in pure silicon, however, that they aren't very useful. Our impure silicon with phosphorous atoms mixed in is a different story. It turns out that it takes a lot less energy to knock loose one of our "extra" phosphorous electrons because they aren't tied up in a bond -- their neighbours aren't holding them back. As a result, most of these electrons do break free, and we have a lot more free carriers than we would have in pure silicon. The process of adding impurities on purpose is called doping, and when doped with phosphorous, the resulting silicon is called N-type ("n" for negative) because of the prevalence of free electrons. N-type doped silicon is a much better conductor than pure silicon is.

Actually, only part of our solar cell is N-type. The other part is doped with boron, which has only three electrons in its outer shell instead of four, to become P-type silicon. Instead of having free electrons, P-type silicon ("p" for positive) has free holes. Holes really are just the absence of electrons, so they carry the opposite (positive) charge. They move around just like electrons do.

When the N-type silicon together with P-type silicon. Every PV cell has at least one electric field. Without an electric field, the cell wouldn't work, and this field forms when the N-type and P-type silicon are in contact. Suddenly, the free electrons in the N side, which have been looking all over for holes to fall into, see all the free holes on the P side, and there's a mad rush to fill them in.

6.5 How long a solar cell can be operated?

Solar Cells are rugged, dependable devices for converting sunlight directly into electrical energy. They have no moving parts and a long working life. System maintenance costs are lower and reliability is much higher than for other power sources. They can be used on any scale, from powering a digital watch to running a multi-megawatt generator for a public utility. Because they are usually arranged in modular panels, it is possible to start with a small system and expand it as necessary without making the early panels obsolete. But because only small amounts of energy are converted by each cell, large-scale electrical requirements require large and costly arrays of PV cells. Thus, the main applications of PV cells have been to supply relatively low demands. Planners who may be considering long-term economics should also consider that selecting PV power helps to achieve a pollution-free environment.

About 1 kilowatt (kW) of radiant power falls on a square meter (sq m) of the earth's tropics at midday. If a solar panel has an efficiency of 10%, then each square meter of cell array will generate a peak of 100 W of electrical power. A typical 10-W panel, capable of keeping an automotive battery charged, measures 31 cm by 35 cm including the frame. The solar cell energy can be generated for the vending machine usually up to 8 hours after the sun drop.

7.1 Hardware

Below is the list of hardware need in our project. It has been sorted according to priority.
1. Solar cell
2. AGM battery
3. Outer casing
4. Machine dimension and weight
5. Control panel
5.1 Weatherproof touch screen LCD panel
5.2 Coins validator
5.3 Notes validator
5.4 Balance return slot
6. Product display panel
6.1 Robotic arm
6.2 Display panel
6.3 Output tray
6.4 Product that will be displayed at the display panel
7. Security system
8. GSM Modem
9. Advertising (sticker mounted at machine’s body and appearing at LCD screen)
10. Sticker mounted at the body telling that who should they call in case of emergency happen

1. Solar Cell

Quantitative /numeric
Solar cell : 1

The solar cells that we see on calculators and satellites are photovoltaic cells or modules (modules are simply a group of cells electrically connected and packaged in one frame). Photovoltaic’s, as the word implies (photo = light, voltaic = electricity), convert sunlight directly into electricity. Below is the picture of solar cell.


The capacity of energy’s that been expected for the vending machine around 120W to operate the machine smooth and without any problem occur. Our group make a research and we found that the mechanism that suitable for the vending machine is the product that distribute by BP.

These are the details:

i.Performance
Rated power 125W
Module efficiency 12.4%
Nominal voltage 12V
Warranty 90% power output over 12 years
80% power output over 25 years
Free from defects in materials and workmanship for 5 years

ii.Configuration
BP 3125S Clear Universal frame with LoPro junction box and polarized
Multicontact (MC) connectors
BP 3125U Clear Universal frame and robust junction box

iii.Qualification Test Parameters
Temperature cycling range -40ºC to +85ºC for 200 cycles
Damp heat test 85ºC and 85% relative humidity for 1000h
Front & rear static load test (eg: wind) 2400 Pa
Front load test (eg: snow) 5400 Pa
Hailstone impact test 25mm hail at 23m/s from 1m distance

iv.Quality and Safety
• Manufactured in ISO 9001 and ISO 14003 certified factories
• Conforms to European Community Directive 89/33/EEC, 73/23/EEC, 93/68/EEC
• Certified to IEC 61215
Module power measurements calibrated to World Radiometric Reference through ESTI
(European Solar Test Installation at Ispra, Italy)
Framed modules certified by TÜV Rheinland as Safety Class II (IEC 60364) equipment
for use in systems up to 1000 VDC
Framed modules listed by Underwriter’s Laboratories for electrical and fire safety
(Class C fire rating)
Approval by Factory Mutual Research in NEC Class 1, Division 2, Groups C & D hazardous

These graph prove that the efficiency of this solar cell.

Picture 9. Solar cell efficiency.

v. Typical Electrical Characteristics : BP 3125
Maximum Power (Pmax) :125W
Warranted minimum power :119W
Voltage at Pmax (Vmp) :17.6V
Current at Pmax (Imp) :7.1A
Short circuit current (Isc): 7.54A
Open circuit voltage (Voc) : 22.1V
Temperature coefficient of Isc : (0.065±0.015)%/K
Temperature coefficient of Voc: -(80±10)mV/K
Temperature coefficient of Pmax : -(0.5±0.05)%/K
NOCT (Air 20ºC; Sun 0.8kW/m2; wind speed 1m/s): 47±2ºC
Maximum series fuse rating : 15A (BP 3125S) / 20A (BP 3125U)
Maximum system voltage :1000V (IEC 61215 rating)
1000V (TÜV Rheinland rating)

vi. Mechanical Characteristics BP 3125
Dimensions (mm) :1510 x 674 x 50
(Overall tolerances +/-3mm)
Weight (kg) :12.0
Frame :Clear anodised aluminium alloy type 6063T6. Silver Universal frame.
Solar cells :36 cells (157mm x 157mm) configured geometrically for a 4 x 9 matrix connected in series.
Junction box : (BP 3125U) IP54 junction box with 6 terminal screw connection block, accepts PG13.5, M20, 13mm conduit, or cable fittings accepting 6 –12mm diameter cable. Terminals
accept 2.5 – 10mm2 (8 to 14 AWG) wire.
Output cables (BP 3125S) :RHW AWG# 12 (4mm2) cable with polarized weatherproof DC rated Multicontact (MC) connectors; asymmetrical lengths 900mm (-) and 800mm (+).
Diodes : IntegraBusTM technology includes for every 18 cells a Schottky by-pass diode integrated into the printed circuit board bus.
Construction : Front: High transmission 3mm tempered glass. ; Rear: White tedlar; Encapsulant: EVA.

2. AGM Battery

Quantitative /numeric
AGM Battery : 1

AGM BATTERIES are sealed batteries that use "Absorbed Glass Mats", or AGM between the plates. These types of batteries are very rugged. Being maintenance free, AGM batteries are thus ideally suited for use in grid-tied solar power systems with battery back-up. Because they are completely sealed they can't be spilled, do not need periodic watering, and emit no corrosive fumes, the electrolyte will not stratify and no equalization charging is required. AGM's are also well suited to systems that get infrequent use as they typically have less than a 2% self discharge rate during transport and storage. They can also be transported easily and safely by air. Last, but not least, they can be mounted on their side or end and are extremely vibration resistant. AGM's come in most popular battery sizes and are even available in large 2 volt cells for the ultimate in low maintenance large system storage.


Picture 10. AGM Battery

3.Outer casing

We decided that our solar-powered vending machine must use a weather proof body. Throughout a research, we found that an element called PVCU (Polyvinyl Chloride Un-plasticised) is fit for the machine as the element of the PVCU,
1. Not rot or biologically decompose
2. Resistant to weathering
3. Low maintenance requirements
4. Tough on impact
5. Retain its shape within normal climatic temperatures
6. Can be reshaped at very high temperature
7. Can be recycled
8. Cheap
9. Durable

4.Dimension and Weight

Height : 1.9m
Width : 1m
Depth : 1m

The dimension given above is reasonable for inserting these elements into it,
1. Selling product
2. Control unit (which controls the machine’s operation)
3. Coin/Notes validator and case
4. Output tray
5. Coin/Notes balance tray

The purpose of having it big is because to make sure that we are able to fit various selling products into one vending machine and also to store as many product as we could so that the responsible person does not has to frequently come to refill the product.

Weight : approximately 100kg (nett empty)
The purpose of making it heavy is because we want to make sure that this machine will not be easily remove by any unrelated person (i.e. thief, vandal).

5. Control Panel

i. Weatherproof touch screen LCD panel

Quantitative /numeric
LCD panel touch screen : 1

• This is the only medium for user to interact with the machine (Provide a user interface by displaying item/product price and receiving input from user when the product selection is made).
• The LCD monitor is used to display the menu of the vending machine.
• User can select the desired notes or handouts by using the touch screen.
• We choose the weatherproof one as it can be used under various conditions/climate (e.g: rain, hot temperature)

Picture 11. LCD Touch Screen Monitor

ii. Coins validator

Quantitative /numeric
Coins validator : 1

Diffuse sensor for coins stack = 5

• A component of electronic vending machines and other devices that accept paper currency.
• Such devices are found in places that have a need to accept paper currency without requiring the presence of a human attendant
• Give option for user to pay with coins (eg: 5p,10p,20p,50,£1,£2)
• Balance return available

Picture 12. Coins validator.

Below are the requirements for the coins validator:
Name: NV10
Dimensions: 100mm(L) x 86mm(H) x 161mm(W)
Power supply: 12Vdc
Input: 350mA at rest, 1A during acceptance
Max. current absorbed: Max 1A
Operating temperature: 0℃ ~ +50℃
Relative humidity: 5 ~ 95% without condensation
Acceptance speed: 1 ~ 2.5 seconds
Price: $258.61 USD

iii. Notes validator

Quantitative /numeric
Notes validator : 1
Diffuse sensor for notes stack = 1

• Give option for user to pay with bank notes (eg: £5,£10,£20)
• Balance return available but in coins only.

Picture 13. Notes validator.

iv. Balance return slot

Quantitative /numeric
Hopper (balance return slot) = 1

• Provide an output slot for balance return if any (in coins)

Picture. Balance return slot /coin hopper

6. Product Display Panel

Quantitative /numeric
1) Diffuse sensor =1
2) Robotic Arm =1
3) Servo motor =1
4) Driver- grap 2000 =1
5) Main controller circuit =1

i. Robotic arm
This machine uses robotic arm as for purpose of taking the desired product from the display panel to the output tray.

What is Robotic arm?
A robotic arm is a robot manipulator, usually programmable, with similar functions to a human arm. The links of such a manipulator are connected by joints allowing either rotational motion or translational displacement.

When customer selects the product, this robotic arm will take the selected product and removed from its stored position without dropping the product, and carried to a delivery area or output tray. Once the product has been put inside the output tray by the robotic arm, it will block the transmitted light produced by the transmitter to the receiver.

When this condition occurs, the sensor will send a signal to the control unit and control unit will send a signal to the output tray door to open. Once the diffuse sensor receiver receives the transmitted light back (this is a condition where the customer has picked up their desired product), it will send another signal to the control unit. Hence, control unit will send a signal to the output tray door to close back.


Information about the Robotic Arm

SG5-UT(Ultra Torque) Robotic Arm
The SG5-UT, load balanced, robotic arm featuring all aluminum construction and the only fully expandable "smart grip" design components (detailed below). Feature for feature, the SG5 series presents the most powerful and sophisticated, all aluminum 5-axis robotic arm system available today.

Key Features
All parts are precision CNC machined from .063 ga. 5052 brushed, sheet aluminum
The aluminum components are anodized to a smooth, scratch resistant, graphite finish using a type II anodizing process (the most impermeable finish next to military type III anodizing)
All servo pivot points use integrated pem stud pivot points. Pem studs are cylindrically shaped aluminum spacers that are pressed into the aluminum with over 300 pounds of pressure. Unlike other manufactures we do not use tape or glue in these critical stress areas


Integrated pem nuts for ease of construction. Pem nuts are nuts that are pressed into the aluminum with over 200 lbs. of pressure. This makes construction much easier and faster.
Pass thru holes and slots strategically located throughout the arm assembly for convenient wire routing.
2 integrated SPST switches for convenient power routing to servos and supporting electronics.
3 integrated mounting tabs for convenient attachment to your robotic platform

Accommodates all of the Parallax microcontroller boards including the BOE, BS2P40, BS2P24 and others.
The arm incorporates a custom engineered, counterbalanced retract system that effectively ensures maximum lifting and efficient servo power use both during operation and at rest. A counterbalanced arm is critical to ensure long servo life and maximum lifting power.

Sensor Engineered Grip Design
The most critical aspect of any robotic arm is in the design of the manipulator or gripper. A robotic arms usefulness and functionality is directly related to the arms ability to sense and successfully manipulate its immediate environment. We developed the gripper assembly to include the following critical design features:
The gripper assembly contains an integrated, adjustable electronics stand located above the gripper assembly to accommodate an array of CCD cameras, infrared sensors and other sensing electronics.

The gripper contains (4) integrated slots to accommodate multiple sensing opto-electronics components.
The ends of the gripper are rounded for an even gripping surface area regardless of the gripper angle relative to the object being grasped.
The gripper drive system consists of a high resolution, 60 tooth, heavy duty, resin gear train driven by a high torque HiTec HS 475 servo - All of these combined components are critical for firm, precise gripper manipulation of objects.
The rounded gripper ends can conveniently accommodate the "Flexiforce" pressure sensor for precise gripper pressure measurement and control.
1/16" volara, cross-linked polyethylene foam is used to line the inside of the gripper surface for maximum grip adhesion.

This is the actual image of the robotic arm



ii. Display panel

Quantitative /numeric
Limit switch = 35 (5 tray * 7 row)

Display panel is a place where all selling product will be displayed. We decided to make the display as wide as possible because we decided to make this machine able to sell various products in one machine. The tray of displaying the products will be placed slightly higher at the back and it goes lower to the front. This is because we thinking of the products will slide to the front itself (naturally - gravity force) once the most front product displayed has been taken out by the robotic arm as this can save the usage of electricity.

As we mentioned before, the responsible person will not have to come every day just to inspect the machine's condition as we have included the SMS features into this machine's operation. In order to make it happen, we think of placing a sensor at each products tray at the display section. The most suitable place to mount the sensor is at the both sides of tray, and it would be better if it is been placed a bit to the front because it will indicate that the products running empty.

Limit switch is the best sensor that we can think of at this moment because although it is cheap, but it able to function perfectly. This limit switch will give a signal to the control unit once it has not been touched by any products at the tray (this is a signal showing that the product is running empty). Then, the control unit will activate the Logiccode application and hence, a SMS will be send to the responsible person as to notify him that the product is running empty and he needs to take some actions.

iii. Output tray

Quantitative /numeric
Diffuse sensor =1

We choose to have an automated output tray mounted at our machine where it equipped with a diffuse optical sensor.

What is diffuse optical sensor?
Diffuse sensor is one of the optical sensors where both receiver and transmitter mounted at the same place. When the receiver receives a transmitted light produces by the transmitter, it means that there is no object inside the tray but when the receiver does not receives any transmitted light produced by the transmitter, it means that there is an object exist in the tray where it blocked the light from transmitted to the receiver.

The picture below shows the working principle of this sensor.


iv. The product that the machine will display

Solar powered vending machine is one of the most environmentally friendly products ever invented. One of the biggest benefits and organization may gain from using this machine to distribute its products, is the unbelievable amount of money that can be saved on electricity bill. Especially now, when the economy around the world is not at its best shape, we all try to save every penny we possibly can.

It does not require a plug or any cords as it operates on solar panels, which are charged during the day to use stored energy for the night time. This is another advantage – it may be placed absolutely anywhere as long as the sun light reaches the machine’s solar panels.

Choosing different locations for placing the machines does not require much attention, it’s the products that should be sold at those locations need to be thought about very carefully. Taking the beach as an example, still there are not as many vending machines as we would like to see on a sunny hot day in the UK or whole year around in Thailand. Products that may be sold there would include the product as showing below those are the products most necessary at the beach and are not always at the local stores if there are any.


Beach: sun block-first aid- goggles-cigarettes-gum-disposable camera-nuts –charcoal flame-shampoo- plastic cutlery
Desert: phone charger-phone card-read map-tissue-flash light-battery-biscuits- first aid
Garden: crisp- gum-disposable camera-tissue-biscuits-first aid-city map-plastic cutleries
http://www.jun-gifts.com/others/littlethingsjapanese/littlethingsjapanese.htm

7. Security System

We decided to include alarm system in the machine.

How does the alarm works?

The alarm include in the machine will produce a very loud sound if it receives a signal from control unit.

There are 2 possibilities that can contribute to alarm activation. First, we can put a very simple mechanical switch i.e. limit switch to the machine’s door.

What is limit switch?

Limit switch is a switch that provides the function of making and breaking electrical contacts.

The switch will give a signal to the control unit when it is in open circuit condition, hence the alarm will activate. This condition will happen if any inappropriate person tries to open the door (attempt to steal the money or products). We only can disable this system by inserting code lock via user interface (at the screen) which this can only be done by responsible person.

Another thing that has been put into our consideration is the movement of the machine. As the machine can be easily moved, we afraid that it might be taken by unrelated person. We suggest that simple mercury switch to be installed to the machine in order to avoid this thing happen.

What is mercury switch and how does it works?

Mercury switch is a switch where its configuration is similar to LED. It has 2 terminals with a transparent casing and mercury inside. Mercury switch will be in high position if mercury touches both terminals. The configuration is been shown in the Picture 16 below.

So, if mercury touches both terminals, it will give a signal to the control unit, thus alarm will be activated.


Picture 16. Construction of mercury switch

8. GSM Modem

Quantitative /numeric
GSM Modem =1

GSM Modem is needed because it is essential to have it in order to include an SMS features in our project.

Below are the details or requirements of GSM Modem needed:
• Size
• Weight
• Power consumption
• Power supply
• Temperature
• Frequency coverage
• Interfaces


Picture 17. GSM Modem

9. Advertising

We think of equipped the machine with advertising space. The way of advertising that we decided is by sticking the sticker on the machine’s body. Why we choose that is because it does not require any power from the machines but at the same time we able to gain some profits.

10. Any emergency case happen

We are considering to put the telephone number of the responsible person at the body of the machine where people can easily found, if any emergency case happen i.e. coin is stuck or any other emergency cases that might arise.

7.2 Software

1. Visual Basic

A software development tool used to interface hardware and software. We plan to use this software as the main controller of the machine to operate efficiently. Input devices such as sensors and limit switches will be interfaced with other controlling devices such as robotic arm and DC motor through this software. Visual Basic also will become the main platform for Logiccode GSM SMS ActiveX to operate in order to enable the SMS alert system.

2. Logiccode GSM SMS ActiveX

Logiccode is a software that been used to create a coding for SMS. It been used together with the Visual Basic software. Below is the brief description about this software.

Logiccode csed to read/delete SMS, send WAP Push and send text messages in English or Unicode supported languages using GSM modems/mobile phones connected to serial port by data cable, bluetooth or IR. This software works together with Visual Basic as it main platform, to send a SMS alert to responsible person (technician/supplier) when selling product is running out and during the emergency alarm is activated.

As mentioned earlier, we decided to include SMS (short messaging service) features into our system.

Why include the SMS features?

One of the reasons is to monitor the machine. Once control unit gives a signal to alarm, it also running a code that generates a SMS to notify the responsible person (i.e. technician) telling that alarm is activated, please take some actions.

The other reason is to notify the responsible person that the coin/notes is almost full and the selling products are running empty.

Below is a block diagram showing the overall overview of how the security system of the machine.

8.1 System Plans

We are planning to include 6 different systems into our machine. There are

1. Power generating & storing system

• Like what we have mentioned before, we are getting the power which needs to deliver to the machine from the solar cell. Also, the power that we obtain from the solar cell will be stored in the battery as well.

2. User interface system

• We choose to have a slightly different user interface than the normal vending machine has. What we mean here is that we are using touch screen in order to interact with the user as we believe that it is more user friendly and sophisticated.

3. Robotic arm system

• Robotic arm mounted on a vending machine is something that is new to all of us. Why we choose to have a robotic arm is because we think that it will bring the desired item to the output tray in a proper manner (where the normal vending machine only use a gravity to make the desired item go to the output tray).

4. SMS notification system

• We believe by having this system, it will make us easier as it able to notify us when the product running empty, when the coin that used as a change running empty and when something not good (vandal or people trying to open the door without permission) to the machine.

5. Product availability system

• As mentioned before in the point number 4, we can easily know when the exact product displayed in the display panel is running empty. This is just by placing a sensor at every row in the tray. As the sensor gives a high signal to the control unit, which means it is a signal to add the item in the product display.

6. Security system

• This is a critical system for our machine as it could protect the machine from irresponsible people. We decided to install an alarm system that will be triggered on when someone try to hack or damage the machine. Apart from that, the system will make the machine send a notification text message to acknowledge the supplier / owner.

8.2 Architecture Plans

1. Solar cell placement

By looking at those 2 machines (existing machine and proposed machine), we can see that the placement of the solar cell is still the same (at the top). This is because we believe that by placing the solar cell at the top, it able to absorb more sunlight.

2. Outer casing

We decided that our solar-powered vending machine must use a weather proof body. So, we choose PVCU (Polyvinyl Chloride Un-plasticised) as from the research, it prove that it is fit for the machine as the element of the PVCU,

1. Not rot or biologically decompose
2. Resistant to weathering
3. Low maintenance requirements
4. Tough on impact
5. Retain its shape within normal climatic temperatures
6. Can be reshaped at very high temperature
7. Can be recycled
8. Cheap
9. Durable

3. Machine size

The purpose of having it big is because to make sure that we are able to fit various selling products into one vending machine and also to store as many product as we could so that the responsible person does not has to frequently come to refill the product.

4. Machine weight

Weight : approximately 100kg (nett empty)

The purpose of making it heavy is because we want to make sure that this machine will not be easily remove by any unrelated person (i.e. thief, vandal).

8.3 Software Modules

In order to make our machine become much different from existing ones, we added a few features such as LCD touch screen and SMS notification for supplier / owner. These features involve the using of specific software to make it works.

1. Visual Basic

We decided to use Visual Basic as the main development software to interface the program and hardware (LCD touch screen, robotic arm, output tray motor, money acceptor). Hence, we also need to install a mini computer (Windows based) inside the machine in order to work with Visual Basic.

A GUI need to be designed in Visual Basic such that it would be appearing as a user interface at the LCD touch screen. The software take the input from LCD panel (touched by user) and give a output signal to the robotic arm to perform it task depending on each one’s programming scheme.

Visual Basic also will take the input signal from money acceptor in order to display the current amount of money inserted by the user. Apart from that, by using the software we also going to make the screen display short videos at the GUI for advertisement purpose during the idle mode.

2. Logiccode GSM SMS ActiveX

As for the SMS notification feature, we need to use this software which is work together with Visual Basic as it main platform. Basically, this software is used to read or delete SMS, send WAP Push and send text messages in English or Unicode supported languages using GSM modems or mobile phones connected to serial port by data cable, Bluetooth or IR.

In this case, we are going to use a small GSM modem with serial data cable which will be connected to the mini computer. The software will make the modem send a notification text message to the owner / supplier if the selling product number is running out, the money stacks (at the money acceptor) is almost full and when emergency alarm is activated.

This will happen when the respective sensors are triggered by the stated conditions and Visual Basic will take them as input signals and responding by making the modem send the message right away.

8.4 Drawing and Charts

Below is the general working principle flowchart that shows overall step by step procedure that happens inside the machine


Below is the flowchart on how solar cell and battery works on our project


Below is the flowchart that shows how robotic arm works on our project


Below is the flowchart on SMS works on our project

8.5 System Integration

Below are the various systems that appear to have in our machine.

8.6 User Interface

For our vending machine, we going to use a little bit different user interfaces compared to existing vending machines. Basically, our machine interacts with users through 4 main features:

1. Product display
We use a large clear PVCu panel (which covers most of the front face of the machine) to make the selling products are visible to users before they want to purchase. These panels are non-pastic and non-glass material which is tough and flexible to be used outdoor and it also proven as weatherproof as it has been used for existing solar vending machines.

We still want to keep this method of displaying product as it shows the real products and their availability through the clear panel to ensure the user that he/she get exactly what the customer sees.

2. LCD touch screen
We choose the 8.4" All-Weather VT084XA weatherproof LCD touch screen to be installed at the front face of the machine as a user interface. The touch screen provides an interactive user interface for user to select a desired product to purchase.

Unlike other vending machines, a virtual keypad will be displayed at the screen when a sufficient credit is provided by the user. The user can select product by pressing the keypad according to the coordinate of the product (combination of a letter and a number, just like typical vending machine. eg: D5 ).

During an idle mode where the machine is not being used for a period of time (which can be set according to the owner), the LCD screen alternately will display preloaded advertisement videos one at a time. The video will be cleared when a user want to buy something from the machine by simply touching the screen.

3. Money acceptor / balance return
For this feature, we are going to use 2 types of money acceptors; coin and notes validators. With this, users will be always have an option either to pay with coins or bills during the product purchasing. This feature works just like in ticket machines that widely use at the cinemas and train stations.

If user selects a product which the price is lower than the money he/she have inserted, the machine will return the balance in coins. However, we just make the machine accept at most £20 notes for UK region (applies for other regions with similar scale) for user convenience.

4. Product dispenser
There are 2 main components involve in this feature; the robotic arm and output tray. Both components have their own driver board (which controls their movements since they use electronic motors) attached to the main board.

The robotic arm is used to pick selected product that is chosen by user using the touch screen an put it into the output tray. It has an embedded chip that becomes a microcontroller which is programmed to pick a product at specific coordinate and put it to one specific place.

There is also an optical sensor at the output tray to indicate that a product is there and ready to be dispensed to the user. Once the sensor detects the product, it will trigger the motor at the output tray to rotate such that the output tray will be opened for user to take the product.

9.1 New companies, product, technology or legislation

Could the product sell?
This solar powered vending machine is one of the most quality vending machine nowadays. The ideas are to vend the products without a cashier and without power electricity. Unlike other types of vending machine, this machine does not need a direct power from main socket to operate. Hence, it can be placed far away from any building, as long as it could reach the sunlight.

By using the solar power to operate the machine, it will reduce the domestic electrical energy usage by using other alternative power source. This solar powered vending machine can also save most of your money every time you get your power bill. Moreover, we also can reduce the energy usage which comes from the mains(plant) and at the mean time we can also save space and can buy items anytime(day and night).

We are dedicated to helping the independent vending machine owner operator gain huge success in industry. Our solar powered vending machine business opportunities exist almost anywhere for entrepreneurs to make excellent money without spending a lot of time.

Furthermore, one of the most important aspects that we focus is on the location to place our solar powered vending machine. Then we can target our market and generate the greatest amount of profit.

Beach is the most suitable place that we might think of putting this machine at because people will definitely buy some drinks or snacks after spending couple of hours playing beach volleyball, surfing or even swimming. It is convenient to have this machine close to the beach as people will easily go and buy the items wanted rather than place it far from the beach.

If we look at the Asian Middle East country, almost every part of the countries is covers with dessert. It is difficult to get electricity source directly from the mains. So, that is why this machine is perfect for them as the problem of having difficulties to get electricity source can be eliminate. Furthermore, Asian countries have no problem to receive enough sunlight as it situated at a portion of the world that able to receive enough sunlight every day.

9.2 Examining the Weaknesses of Existing Products or Companies

Will the market need our solar-cell vending machines?

As our research, we found that the demand of using new energy is more and more necessary. As recent decades, the ever- increasing number of environmental disasters make all people have to rethink about their life.


As all of the research and reports, one reason of the increasing heat of the earth and the change of climate in all continents come from the exhausted sources and our bad habit of using energy. However, the human beings realize the essential role of energy. Hence, people prefer the friendly-to-environment power. As the result, we do believe that our products will receive a huge support from citizens.


In fact, there are more and more products using the solar cell as the source of power such as the new calculators or radio for the personal purposes and space probes, water pumping application, or Earth-orbiting satellites for the researching purposes. Another famous example of robot using the solar cell is “Roving Mars” for the purpose of exploding Mars, and the robot brought us the valuable result. Indeed, the advantage of using solar cell is the mobility. For some cases, we cannot finish our mission without the solar cell.


Meanwhile, almost all of the vending machines now in the world still use the electricity as the main source of working. People still do not have the habit of using the kind of energy. However, we think that it is our chance in this field is quite huge because the market is still not fixed.


But in the near future, all of the normal machines will be replaced by ours because of human beings’ increasing demands.


Comparison to Existing Products

There are some products on the market that also use the solar cell as the power source. In this part, we will also compare our products with some of the existing products in our main purposes.


Saving the energy and the maintaining cost
The large solar cell on the top of vending machines will save the electrical energy. Hence, when comparing to a normal vending machines, our product has big advantages because it really not only the new friendly -environment energy source, but also save a big amount of money. In fact, may be one machine can only save a little amount, but with a system of vending machines with hundreds of products, the maintaining cost and electricity bills are not little, and our machines, hence, cannot be beat in price because of huge amount of money has been saved every year.


Mobility
Another advantage of our products is the mobility. Indeed, using solar energy can make our machines work in many different areas. Compared to many other normal vending machines, we can found that the idea of motility is so important. The normal vending machine sometimes cannot be placed in beaches or parks because of no electric source. However, our new vending machine will be useful in many places such as beach, public places such as parks, schools or even deserts.


Indeed, the solar energy can bring the mobility for nearly all products using it because we can get the solar energy everywhere. For instance, there are also many products that have the same aim also use the same kind of energy such as Earth-orbiting satellites and space probes, remote radiotelephones and water pumping applications.


The comfortable element
One of the important elements comes from customer, we want our products make all customers feel comfortable when use them. Hence, we put a small LCD screen on the vending machines. It will make all customers feel better and easier when choosing items. Moreover, we also put a speaker for all blind people.


Compared to a normal vending machine, we think that this is a big difference when the normal vending machine often does not have it. In our opinion, the element is every important because it is a public machines. So our task is that making all people can use it easily.

9.3 Knowledge of Customers/Users

Before researching to develop our product, we realize that our customers will be different to the end user.


Our customers

We think that the target customer will be big companies, but not personal cases. In fact, our products are for public use, but not only one. Apparently, there will be no one who will buy a vending machine to use at their house. Hence, I think that we will pay attention more to the companies. There are many kinds of companies who will be interesting in our products, but we will temporary class them by two.


The first kind is the big companies having products or manufacturers, and they want to expand their market in the public places such as Coke or Pepsi. Even the retailed-market is not always one of the best ways to invest with the big companies, and it is a good chance of advertise to them. So, when comparing between vending machines and building and maintaining a small shop to sell their only one product, we think that the first one will be their choice.


The other kinds of companies are those who pay more attention to the retailed-market. They do not have any products, but they sell many kinds of products and get the profit between the buying and selling prices. In fact, the business kind can include big companies or only some small groups of people who invest together in only one shop. Actually, in the second kinds, they also have shops, but they still want to invest more by using vending machines.
However, the both two kinds only have a same purpose that is profit, including reducing the maintaining prices and the first- time amount of money invested. All of these are also our purposes.


Obviously, maintaining vending machines will be much cheaper than a shop, including the fee for renting the house, the fee for vendors, etc. Our product has the big advantages compared to shops, especially to the first kind of companies. Besides, we also have good securities, we think that it is a point that all of our customers also have to consider because all of the vending machines will be placed in the public places. Hence, security is always an important element, because no investors want to pay more money to repair the damaged products.


Meanwhile, compared to the other normal vending machines, our product does not need the electrical source. Moreover, our product uses the green power. In the development period today, people pay more and more attention to the environment. They prefer the friendly – to –environments products. Hence, we think that our products will receive the much supporting from the public. Finally, with all of the advantages, we do believe that our products will be a good choice with all of the companies.

Our end users

We found that our end users will be all kind of people, because our products are for public use. Hence, to make our products increase the competitive element, our purpose is make the vending machine is so friendly to user. Instead of using buttons to control, we have a LCD, and that is a touch screen. All things will appear on the screen, the users will find there wanted product easily.


Moreover, with the screen, the user can control all what they want. The screen wills not only help the user fell easier to use the machines, but it also make them more so interesting in our products because of our designs.


For example, they can change the product by changing product before confirming them. Or they also can know exactly, they amount of money they put on the vending machines and the changes for them. Moreover, the output tray is automatic will help the customers easily to get their items. Besides, we also put a speaker to help the blind people. After all, we think that user will be comfortable when using our products.


In conclusion, we found that even our customers and the end users are different but they have a close relationship because the end user will be the customers of our products buyers. Obviously, one of the most priority elements with our customers is profit, but the feedbacks from the end users will also be an important element that investors have to consider.

9.4 Knowledge of Geographical Regions

One of our main purposes is the mobility element. Hence, we always have to pay attention to the geography regions of the products.


At the first time, we choose the tropical countries such as the ones in the South East Asia or dry areas such as Egypt or Arab Saudi

.
In southwest Asian, the climate is mainly tropical–hot and humid all year round. There is a lot of rainfall.


Southeast Asia has a wet and dry season caused by seasonal shift in winds or monsoon. The shinning period is not really different between the summer and winter. Besides, there are many large beaches in the countries. And they are developing countries, the competition, hence, is not as hard as that in the developed countries.


Besides, in the dry areas such as Asian Middle East countries, the time of shining is fixed with the high intensity. It is a good condition for our product work well. Besides, there are a lot of landscapes there. We think that with the huge number of visitors in the places, our products can have good opportunities in the places.


We think that the two kinds of area will always be the first choice to invest.


After that, we think that we will have to expand our market in the Europe. The continent has a variety of climates, but most of the continent has mild weather. But the shining time of the countries are so different between the seasons. For example, in the UK there will be more than 12 hours of shinning a day in the summer, with the high intensity and the shining time, our products can work well in the period.


However, in the winter, the shinning time is only 6 to 8 a day with a so weak light. Moreover, in some bad weather such as mist, raining for a long time or snowing, we think that our products will do not have enough energy to cover the work of machines. But we also put a battery on the machines.


As our research, we found that even for one day of weak light energy, our machines can still work well. However, in the case of snowing, the snow will cover all of our solar cell and it cannot get energy from light at that time. Hence, we think that our product can work well in the summer, but in the winter, it will be depend on the local weather at those places.

Weather
One of our main purposes is the mobility element. Hence, we always have to pay attention to the geography regions of the products. First of all, we choose the tropical countries such as the ones in the South East Asia or dry areas such as Egypt or Saudi Arabia. In southwest Asia, the climate is mainly tropical, hot and humid all year round. There are a lot of rainfalls. South East Asia has a wet and dry climate caused by seasonal shifts of winds or monsoons. The sunshine period is not really different between the summer and winter. Besides, there are many large beaches in those countries. Also those are developing countries, and the competition, therefore, is not as tough as that in the developed countries. Besides, in dry areas such as Middle East countries, the timing of sunshine is set with the high intensity. It is a great condition for the work of our product. Besides, there are a lot of sights there. We think that with the huge number of visitors in those places, our products can have excellent opportunities.
We think that those two kinds of area will always be the primary choice to invest in.

Furthermore, we will have to expand our market to the Europe. The continent has a variety of climates, but most of it is mild. The amount of sunshine in these countries is very different between the seasons. For example, in the UK there is more than 12 hours of sunshine during the day in the summer. With the high intensity and the amount of sunshine, our products can work well during that period. However, in the winter, there is only 6 to 8 hours of sunshine a day with such a weak lighting. Moreover, in some bad weather conditions such as mist, rain for a long time or snowing, we realized that our products will do not have enough energy to cover the work of machines. However, we attached solar batteries to the vending machines. As our research shows, even having one day of weak direct lighting, our machines can still work well. However, in the case of snowing, the snow may cover all of the solar cells and it cannot get energy from the light during that time. For this reason, we think that our product can work well during the summer, but in the winter, it will be dependent on the local weather in different locations.



There are 3 aspects that need to be considered and followed during the budgeting:
• Determine the part that needs to use
• Determine the price of the part
• Compare the quotation

AUDITING METHODS OF COSTING

COST ESTIMATION FOR SOLAR POWERED VENDING MACHINE

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*estimated price after conversion from USD
* *estimated price after conversion from Malaysian Ringgit

1. Solar Powered Vending Machine (view in different angle)

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