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Steve Holstein and J.R. Allen ECE 345 Project Proposal Introduction Each of us developed the idea for the project independently and found surprising similarities in the functionality when we talked about our ideas. We are both eager to develop this project for the challenging experience of creating something new as well as the marketability we foresee of a working design. This project will at the same time allow us to demonstrate for ourselves the ability to adapt to projects since neither of us are experts on RF communications. By the completion of our project, we hope to have a unit which will communicate with other similar units automatically. A centralized website will coordinate the function of the units by providing software to reprogram the units as well as allowing users to lookup websites managed by the sender. The units will interchange a string and a unit id. The string’s function will be to entice receivers to lookup the sender’s website by typing in the sender’s unit id at the centralized website. In order to control overloading of the unit, we hope to implement a class system for messages, so that messages may be filtered out, i.e. a person at a convention looking for software could filter out all hardware related messages. In maintaining a centralized website which the units depend upon, we add additional marketability to the project by providing a high trafficked area of users seeking specific information which can be used to provide additional advertisements from related groups. While the project is specifically aimed at business conventions, it is our belief that the units could become popular for everyone as a way to meet new people and receive focused advertising. Buttons: Next, Last, Delete MODEM: FSK CPU ROM: UNIT ID, Display PROGRAMMING RAM: String, additional programming, Stored Messages The buttons are used to control the unit allowing to go forward and backwards through the messages and delete old messages. The display shows the contents of the message and the unit id of the sender, along with any navigational messages to assist the user if needed. The ROM contains the unit id which identifies the user of the unit, along with the essential programming information. The RAM contains the unit’s programmed string, the additional programming supplied by an update from the central website, and all the stored messages logged on the unit. The modem controls the interaction of the units by supplying a common channel which units compete upon to deliver their message to other units. The CPU provides the control for the device, managing the communications protocol when in idle, and displaying the messages in response to user input. The communications protocol will be similar to that of ethernet, where all devices wishing to send compete for the channel, setting a random exponential delay each time they are blocked from the channel, until finally only one device gains access to transmit. Performance Required The basic level of performance will be to interchange the pages from multiple units. Once this is accomplished, measurements will have to be taken in order to determine the proper delay settings to ensure efficient use of the communication channel. A well tuned device should be able to interchange messages with no more than a half minute delay for each device added. The range of the device will intentionally be kept small in order to limit the number of units competing in the same area. We assume that the people carrying the units will move around and therefore the units will be able to compete with all other units in a finite amount of time. Therefore a good performing range will be maintained to a 40 ft. radius. Quantification Once the message has been successfully sent. The unit’s message length will be adjusted to achieve a balance of string size to transmission time. This data will be tabulated on a graph and used to set the delay for the device. The delay for the device will use the data from the graph of message length vs. transmission time to simulate channel competition on a computer. The random delay will be tuned by the simulation to find a maximum of throughput with a minimum of competition delays. This data will also be tabulated in graphic format to illustrate the role of channel competition in device functionality. The range for transmission will be tabulated by recording transmission times vs. distance between units and the output power of each unit trimmed to 40ft. Schedule Date Items to be Completed 2/14/00 Receive parts, read technical documents, design RF section of unit Discuss RF section of unit and the communications protocol, design the CPU to 2/18/00 RF interface 2/21/00 Programming; communications protocol, menu system, serial download 2/25/00 debugging and testing. 2/28/00 Debugging and testing 3/2/00 Simulation coding to achieve optimal exponential backoff delay 2/6/00 Debugging and testing Cost —Labor $30/hour x 2.5 x 100 hours/person x 2 people = $15,000 —Parts 2 Motorola HC08GP20 8-bit microcontrollers $20 2 2-line LCD displays $10 2 FSK modems 6 pushbuttons $10 Various op-amps, resistors, capacitors, wires, ribbon cables, sockets, and transistors $40 Total: $80 TOTAL: $15,080 Engineering Specifications Test We will test the resistors in the output section extensively to limit transmit power to the appropriate range.
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