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Restaurant Ordering System

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Our Restaurant Point Of Sales (POS) system provides a cost effective solution to ... 65 mA dc vibrator. Receiver. Schematic. RS232 from Computer ... – PowerPoint PPT presentation

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Title: 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
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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 orders 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
Microchip Pic16F688 With built-in EUSART
3v dc supply From 2x AAA batteries
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 1x1 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 dont 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)
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