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This essay does not describe an existing computer program, just one that should exist. This essay is about a suggested student project in Java programming. This essay gives a rough overview of how it might work. I have no source, object, specifications, file layouts or anything else useful to implementing this project. Everything I have prepared to help you is right here.

This project outline is not like the artificial, tidy little problems you are spoon-fed in school, when all the facts you need are included, nothing extraneous is mentioned, the answer is fully specified, along with hints to nudge you toward a single expected canonical solution. This project is much more like the real world of messy problems where it is up to you to fully the define the end point, or a series of ever more difficult versions of this project and research the information yourself to solve them.

Everything I have to say to help you with this project is written below. I am not prepared to help you implement it; or give you any additional materials. I have too many other projects of my own.

Though I am a programmer by profession, I don’t do people’s homework for them. That just robs them of an education.

You have my full permission to implement this project in any way you please and to keep all the profits from your endeavour.

Please do not email me about this project without reading the disclaimer above.

DeLaRue InstaChange coin dispenser
DeLaRue InstaChange coin dispenser
Every office has a small box of cash that is used to handle petty expenses. There is always a problem of theft and error since so many people have access to it, including people who don’t work in the office. It is a nightmare for the person assigned the task of reconciling the cash. Your task is to create a miniature ATM (Automated Teller Machine) machine to manage petty cash and ensure the records are kept perfectly and nobody takes money without a record of it.

The software

It consists of a computer that people can type on to make their petty cash requests. They can’t get any money without specifying the amount and the purpose to the computer. People can identify themselves with various types of id card, fingerprints, flash drives, passwords etc.

Management can limit different employees in amounts and frequency, or require authorisation.

All this is handled with a traditional GUI (Graphic User Interface).

The first thing someone would think of to foil such a machine is to take out money, then pull the AC (Alternating Current) power plug and hope the machine forgot about the money it just gave out. You have to strongly commit transactions to hard disk before handing over any cash.

The Hardware

The cash itself is stored in what amounts to a miniature ATM. There is no need for it to be built like a safe. We are trying to discourage petty theft here, not a bank heist. You can’t use an actual ATM machine since it won’t dispense change.

It dispenses coins using the same mechanism as a vending machine. Presumably you can get such a device by scavenging it from an old vending machine or finding supplier of new components. You could look for ideas and parts on Google from ATM manufacturers, bill breakers, vending machines, bank teller cash dispensers, night cash dispensers, cash recyclers, coin dispensers supermarket cash registers that dispense coins to the customer, multiple denomination bill dispensers…

You might build it around the DeLaRue InstaChange automatic coin dispenser.

To dispense the money you might use the mechanism for a sheet-feeding printer. Alternatively, you could use a tractor feed mechanism and put the money in pouches mounted on tractor feed paper. That takes more work to load the machine, but it would hardly ever jam if you had a rugged tractor mechanism. Probably it would be cheapest and most reliable just to use one of the many existing multi-denomination bill dispenser components.

The deluxe model would accept bills and coins as well, the change for some purchase made with petty cash.

Low Cost

The key to making this project a success is to keep costs low. A business can’t justify spending that much more than it saves in petty thefts. It is worth something to a business to remove temptation. It is also worth something to have accurate books. Suspicion over petty cash creates crippling dissention. You can reduce the cost by having it run on some old computer that has been retired.
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