Transcript PPTX - Purdue College of Engineering

Dan Chambers, Josh Marchi, Jeff King, Paul Rosenberger
 “Reverse Geocache” Box
 Locked box that will only open after one or more pre-
determined GPS locations have been visited
 Directs user to next location by GPS coordinates or
text displayed on LCD, or by an LED compass
 Route stored on microSD card located inside the box,
able to be reprogrammed by PC
 RFID “master key” to allow access to box without
finishing puzzle
 An ability to obtain and decode global positioning data in
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order to verify if current location matches pre-determined
desired location.
An ability to utilize accelerometer and magnetometer data
to determine a compass heading with tilt compensation.
An ability to access and interpret files located on a microSD
card.
An ability to display information to the user via an LCD
display.
An ability to identify an RFID tag using an RFID reader.
 Computation
 GPS Coordinate analysis, tilt compensation calculations
 Communication
 Interact with GPS, RFID, Compass, LCD in a timely
fashion
 Battery Powered Device
 Low power usage / rechargeable battery
 Packaging
 Compact, “personal-sized” box
 Compass heading / tilt compensation (polled)
 Floating point values, trig functions required (lookup
table)
 GPS coordinate analysis (1Hz)
 Distance from target
 SD card file system, interface library
 Large amount of Flash/SRAM
 Receive data from a variety of sensors/modules
 GPS, RFID, Accelerometer/Magnetometer
 Read data from MicroSD card
 Output audio to speaker
 Control servo locking mechanism
 LCD Display
 Parallel GPIO / shift register (6 - 12 GPIO pins)
 LED compass ring
 Shift registers (2 GPIO pins)
 1-2 Pushbuttons (GPIO)
 3 UART Modules
 GPS, RFID, Debug
 1 SPI Module
 MicroSD interface
 1 I2C Module
 Accelerometer / Magnetometer
 2 PWM Channels
 Speaker, Servo Control
 2+ Output Compare Timer Channels
 Compass polling, LCD strobe
 PIC24FJ256GA106
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16 Bit Architecture
16 MIPS CPU speed
256KB Flash
16KB RAM
Memory Disk Drive File
System Library Support
4 UART Modules
3 I2C Modules
3 SPI Modules
64 Total Pins
 GPS Module
 RFID Receiver
 Digital Compass
 Accelerometer/Magnetometer
 Serial to USB Bridge
 Debug
 Trimble Copernicus II
 Time to first lock: 38 sec
 Dual serial ports
 Reconfigurable UART
rates
 Position Accuracy:
<2.5 m 50%, <5 m 90%
 LSM303DLH
 +- 2/4/8 g Accelerometer
 +-1.3 to +- 8.1 gauss
Magnetometer
 I2C Serial Out
 Excellent application
notes for tilt
compensation
 Battery powered device
 Lithium-Ion Polymer single cell battery (3.7 VDC)
 3300 mAh
 Multiple operating voltages
 Micro, GPS, MicroSD, Compass (3.3V)
 LCD, RFID (5V)
 Two converters be used to regulate both voltage levels.
 Must be rechargable
 MAX1555 USB battery charger IC will be used
 Allows charging through USB or additional DC source
 Highly durable
 Easy to carry
 Relatively small in size
 Should be able to receive GPS signal from within the box
through an antenna
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Pelican 1150 Case
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Inside dimensions 8-3/8" x 5-7/8" x 3-11/16"
Outside dimensions 9-1/4" x 7-9/16" x 43/8"
Lid Depth 3/4"
 Most expensive: GPS receiver - $80
 RFID kit - $50
 Digital Compass - $30
 GPS, RFID, and Compass initially include breakout
boards, which increase their cost
 Box should not exceed $300
 Box made without breakout boards would cost less
than $225