Requirements Specification

Background:

           Human service corporations provide housing for mentally challenged and disabled individuals called clients that can not carry out certain tasks that a normal person may take for granted like going shopping to the supermarket. At the same time many refrigeration companies have been striving to create a refrigerator that can distinguish themselves from their competitors.
           The clients that are placed in group homes are in need of a way that can help them to get their shopping done without them having to leave their homes. This need can be met with a refrigerator that can create a shopping list for clients and inform some remote site what the client need for food. Existing grocery delivery companies will raise prices for their services and refrigeration companies will raise prices for their products.
           This prototype will change the whole refrigeration industry. Human service companies will not be the only ones that will be able to purchase such a refrigerator, but grocery shoppers whom are tired of going to grocery stores and waiting in long lines will be in need of this type of refrigerator as well.
          

The Deliverables: There are five deliverables as listed below:

           1. A working prototype of the electronic components, not including packaging.
           2. The following documentation:
           a. wiring diagram
           b. parts list, assembly drawings, and assembly instructions
           3. User’s Manual
           4. System Specification, including the design concept, block diagram, functional description of the blocks,a
           system description, and any analysis done during system design.
           5. Schematic diagrams and circuit descriptions.

Special Restrictions:

           1. Any wireless devices used must adhere to federal regulations.
           2. Care must be taken to preserve the privacy of every user. This means protecting the information
           collected and stored within the web server.

Principle of Operation:

           A database containing information about the status of the sensors will be periodically updated on a server via a wireless connection. A user may obtain the status of the sensors by viewing a LCD screen that may be embedded into an appliance. Alternatively, a user may log in to the web server containing the database and potentially check the status remotely. Furthermore, the possibility exists to send an email or update a handheld wireless device with the most current information. This information is used in discovering what needs exist, and making it easier to fulfill those needs more efficiently.

User Interface:

           The user interface consists of a LCD screen placed on the outside of a refrigerator, a web server that monitors the list of needed goods.

Input:

           The input of this system is the pressure that a container in the refrigerator puts on a pressure sensing device. The amount of pressure varies depending on the amount of liquids or substance in a given container. The device must work within a concealed area with temperatures ranging from 32 to 50 degrees Fahrenheit. This device must also be able to transmit signals dynamically to a LCD screen and a router. The signal from the pressure sensing sends signals at a 360 degrees radius. Too much power consumption is not a huge problem because of the device low power options. It draws 2.8 mA of current, has a RF power level of -10dBm, and a transmission range of 20 feet.
           Describing the pressure sensing device in more depth, the device obtains its data by putting into consideration the force exerted on the device which is Newtons, and the area. This information is taken as an analog value and then converted to a digital value to be sent by a transmitter. The initial input is not the only value that is gained from the force and the area of the container. There are updated values every two seconds being transmitted every 2 seconds. Obtained values from the container will fluctuate as the container loses or gains liquid or substance.

Output:

           The outputs of the system will be the digital signal that is sent to the LCD screen and the router. The LCD screen will show an updated list of the quantity of each container in the fridge with and estimation of when is the next time the consumer will need to purchase more of a given item. A router will receive the signal as well. It will send an updated list to a web server using 802.11. This list will be identical to the list on the LCD screen.
          
           When the consumer buys a container, places the device on the container and places the container in the fridge:
          
           1. The weight of the container is measured.
           2. The measured weight is transmitted to the LCD screen and the internet router.
           3. A list of items and their updated quantities appears on the LCD screen along with a list of repurchasing estimation.
           4. Another list is transmitted to an internet router and is uploaded to a web server.
           5. The above process happens dynamically just about every 2 seconds.

The User’s Manual:

           The automated shopping list is a wirelessly updated list that keeps track of the amount of nutriments in the fridge. It is also used to display the current quantity of each type of food present in the refrigerator. It accurately measures the weight of food in special containers that have pressure sensors at their bottom, and then transmits the current weight via wireless transmitters to a router that transfers the information to a web server. To use the automated shopping list refer to the figure at the bottom of this page and follow instructions below:

• Turn on the LCD screen on your refrigerator.
• Customize the LCD screen on your refrigerator so that it displays the current food status appropriately. You can do so by choosing one of the many display modes.
• Make sure that all the quantities showing up on the LCD are zero.
• Place each nutriment in the special container assigned to it.
• Set up the wireless connection between the containers and the router by choosing the “Establish wireless connection” option.
• If you see “Wireless connection successfully established move on, otherwise refer to the troubleshooting section.
• If you are going to have food delivered, please enter the web server of the delivery company in the setup menu.
• If you see that the quantity of each nutriment changing, the automated shopping list is ready for use.

Acceptance Tests: The performance testing will be done at two levels:

           1. Sales staff from both refrigeration and human services companies will test the automated list and
           make sure that the information displayed on the LCD and sent to the web server is accurate.
           2. After the accuracy tests have been accurate, the time needed to update the quantity of a used nutriment will be tested.
           The product cost test will be based on parts costs as explained in the section on product cost.

Acceptance Tests for weight Accuracy:

           1. Twenty refrigerators of the appropriate model will be selected at random, each with a set of special
           containers. Ten of these will be given to the engineering firm for use in the development of the automated list and
           five will be set aside for use in acceptance testing.
           2. Ten sales staff from both refrigeration and human services companies will do the acceptance testing.
           Each will use a different one of the ten refrigerators and special containers set aside for acceptance testing.
           3. They first check the displayed quantities of the special containers and make sure it is zero.
           4. Each salesman is given a different prototype which includes refrigerators, special containers and a
           desktop to compare the quantities.
           5. The sales staff is asked to place different nutriments in the appropriate containers.
           6. After two minutes they check both the LCD on the refrigerator and the web page and write down the quantities.
           7. First, they have to compare the weights on the LCD’s and on the web page.
           8. Then, they have to weight the nutriments using ultra sensitive scales, and then compare with the values noted previously.
           9. Finally, the sales staff has to write down the error percentage found for each container.
           10. If the automated list design successfully outputs correct weights, then it is deemed acceptable,
           otherwise it is unacceptable.
          
           The parts costs are to be obtained from official manufacturers or distributor quotes based on product volume of 1000 refrigerators. For example, if a component, say a wireless transmitter, is used in two different places, then the cost of that component is based on a quantity of 2 * 1000 = 2000 pieces.

Acceptance Tests for transmission Accuracy:

           1. Connect an antenna to a pressure sensor.
           2. Use a spectrum analyzer with an antenna as a receiver.
           3. Connect the spectrum analyzer to an input port through a buffer of an oscillator.
           4. Make sure that the frequency of the transmitter to the receiver are compatible.

Product Cost

           1. Measuring Senors- $85
           2. Wireless Transmitter- $ 10
           3. LCD Screen –
           4. Wireless Receiver - $80
           5. Web Server
           6. Computer
          
           Total - $175

Dispute Resolution Mechanism

           We will designate a team leader that will oversee the project and have manager type role. He will be some what of the arbitrator and handle all disputes and resolutions and if not then we will consult our project advisor.