Presentation on theme: "Restaurant Ordering System Group 15 Dustin Selvey Joel Ingram April 28, 2006."— Presentation transcript:
Restaurant Ordering System Group 15 Dustin Selvey Joel Ingram April 28, 2006
Introduction Our Restaurant Point Of Sales (POS) system provides a cost effective solution to managing orders, revenue and inventory. The software is complemented with our own cheap and ultra-long range pager system for automatic notification upon order completion.
Features – Software Web server application – why? – Cost effective – Support for any number of workstations – No setup needed for workstations; only a web browser is required – Statistics and current status can be easily viewed remotely – Change service type to remote Open source languages and operating system for server eliminates any licensing costs
Features – Software Tracks food orders from the servers to the kitchen Tracks inventory and statistics Automatically updates revenue and cash flow Manager can access and view status of the restaurant remotely Very generic and modular
Design - Software Server/Database Maintain order database Track inventory Waitress Stations (2-3) Input orders Change orders View order status Kitchen View orders Update order status Electronic Pager Automatically pages waitress upon completion of order Cashiers Station Complete orders / Issue receipts Office View all other nodes View statistics View inventory
Communication Link - Software Simple Linux binary to write characters to a serial port. Database buffer method Two main scripts – Fill database – Read database and transmit Both run as simple cron operations
Communication Link - Software Database buffer method - Requires more CPU power - Constant database activity + Modular + Cost Effective Satisfies Goals
Hardware Concepts The design of an ultra-long range and low power pager system
Features - Hardware Automatic server paging system increases efficiency by immediately and accurately alerting servers to an orders completion Up to 250 pagers are supported on a single transmitter Transmitter communicates with the server through a serial link
Features – Hardware Range coverage of a typical restaurant Battery lifetime of at least one week Small aesthetically pleasing design Programmable addresses allow for easy replacement
Linx 418MHz Long Range RF Receiver Microchip Pic16F688 With built-in EUSART Linx 418MHz (1/4 wave) 50 ohm antenna 3v dc supply From 2x AAA batteries 65 mA dc vibrator Receiver Schematic
RS232 from Computer Max232 chip converts RS232 to 3v signal Linx 418Mhz Long Range RF Transmitter Linx 418 MHz (1/2 wave) 50 ohm antenna 3v dc supply from commercial adapter Variable resistor to comply with FCC regulations
Advanced Design Features To maximize range we use odd parity and start characters for each command To maximize battery life we implemented two separate sleep commands – Sleep Pic – Sleep Receiver To make the pagers easily replaceable we store addresses in flash memory for convenient changes.
Testing - Hardware Input voltage ranges were tested Battery life was theoretically calculated and then proven Range was tested in various environments
Results of Testing Using a half wave antenna will increase the transmission strength by 10db (or 10 times) vs. an unmatched antenna Using a grounded plane at least 3 inches in diameter will increase the transmission strength by an additional 3db (or 2 times).
Results of Testing The input voltage must be between 2.9 and 3.6 volts with no more than 20mV of noise Must be placed at least 6 inches clear of sources of interference (computer, cordless phone, kitchen appliances, etc….)
Results of Testing In an open environment the maximum operating range is 1000 feet. With the transmitter in the senior design lab, reception was strong throughout the south side of the building and intermittent just outside the brick walls.
Results of Testing Theoretical Battery Lifetime – 22 days from Alkaline batteries – 28 days from lithium batteries – 39 days from lithium batteries when the pager is turned off at night Actual Battery Lifetime – Lithium batteries installed on prototype ~March 20 are still powering the receiver at full voltage as of April 26
Results of Testing Limitations of Receiver – Nickel Metal Hydride batteries WILL NOT WORK! – Alkaline batteries are o.k. but NOT recommended Speed Limitations – Maximum transmission: 55.6 kbits/second – Minimum transmission: 300 bits/second Lower transmission speeds reduce both power and range
Antenna Considerations ½ Wave Antenna¼ Wave AntennaGrounded Plane Antenna Large, 7Small, 1.6Very small, internal Best RF ReceptionGreat reception with perpendicular grounding plane; decent otherwise Good reception with perpendicular grounding plane; bad otherwise Chosen for transmitter Chosen for receiver with 1x1 grounding plane
Results of Testing Important Antenna Lessons Learned… – Many structures and traces used within our PCB are antennas – As much as possible we would like to eliminate the use of these structures and traces – If we cannot eliminate them, we must minimize their radiation efficiency – Always look at your design from an antenna point of view – Remember your electronic systems are antennas, and what you dont know about them could hurt you!
Looking Towards the Future… Advanced statistics and inventory tracking Needs to be fully tested in an actual restaurant Built-in rechargeable units to each pager Needs to be verified compliant to FCC Part 15 Class B emission requirements before going commercial
THE END We want to thank the following people for their help throughout our project… Abraham Rozental Alex Spector Andrew Bean Linx Technology (design help) Microchip (free samples)