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 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 ( 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 I 2 C Module Accelerometer / Magnetometer 2 PWM Channels Speaker, Servo Control 2+ Output Compare Timer Channels Compass polling, LCD strobe

PIC24FJ256GA Bit Architecture 16 MIPS CPU speed 256KB Flash 16KB RAM Memory Disk Drive File System Library Support 4 UART Modules 3 I 2 C 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 to 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 Pelican 1150 Case – Inside dimensions 8-3/8" x 5-7/8" x 3-11/16" – Outside dimensions 9-1/4" x 7-9/16" x 4- 3/8" – 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