Restaurant Ordering System

1. Restaurant Ordering System Group 15 Dustin Selvey Joel Ingram April 28, 2006

2. 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.

3. 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

4. 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

5. Design - Software

9. Testing - Software • Test Hardware • Old Pentium III • Gentoo Linux • 256 MB RAM • Very acceptable speed results • A commercial product would have much better performance

10. Testing - Software

11. 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

12. Communication Link - Software • Database buffer method • - Requires more CPU power • - Constant database activity • + Modular • + Cost Effective • Satisfies Goals

13. Hardware Concepts The design of an ultra-long range and low power pager system

14. Features - Hardware • Automatic server paging system increases efficiency by immediately and accurately alerting servers to an order’s completion • Up to 250 pagers are supported on a single transmitter • Transmitter communicates with the server through a serial link

15. 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

16. Linx 418MHz (1/4 wave) 50 ohm antenna ReceiverSchematic Linx 418MHz Long Range RF Receiver 3v dc supply From 2x AAA batteries Microchip Pic16F688 With built-in EUSART 65 mA dc vibrator

17. 3v dc supply from commercial adapter Variable resistor to comply with FCC regulations Linx 418 MHz (1/2 wave) 50 ohm antenna Max232 chip converts RS232 to 3v signal RS232 from Computer Linx 418Mhz Long Range RF Transmitter

18. 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.

19. Testing - Hardware • Input voltage ranges were tested • Battery life was theoretically calculated and then proven • Range was tested in various environments

20. 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).

21. 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….)

22. 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.

23. 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

24. 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

25. Antenna Considerations ½ Wave Antenna ¼ Wave Antenna Grounded Plane Antenna Best RF Reception Great reception with perpendicular grounding plane; decent otherwise Good reception with perpendicular grounding plane; bad otherwise Large, 7” Small, 1.6” Very small, internal Chosen for transmitter Chosen for receiver with 1”x1” grounding plane

26. 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 don’t know about them could hurt you!

27. 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

28. 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)