SafeGuard: Anti-Theft/Reminder TransmitterGroup: #3

Carson HammoserPeter Lin

Albert UangSamuel Wong

The Problem

• Lost and Forgotten Items– Lost Property Office of Transport for London 130 000

items between April 2003 and March 2004– 11300 Laptops, 31400 PDA’s, 200 000 Cell phones

Left in the backs of cabs

• Security– 5035 Pickpocket crimes in London Underground

• Keeping Track of Kids and Pets– 58200 Child Abductions in US

Solution

• A tracking device that warns the user when things are left behind or move too far away

• Able to track multiple items

• Able to recognize each item

Proposed Product: The SafeGuard

• Wireless electronic tether

• Tracks multiple objects on one transmitter

• Audio warning when items are out of range

• Programmable Identification of Item

System Overview

System Overview:

• User places RF tags on selected items– Clip to your Cell

phone/PDA– Slip into your wallet /

jacket pocket– Place In glasses Case– Place in

backpack/briefcase

System Overview:

• User carries an RF Receiver

• LCD Display• Piezoelectric Buzzer• Joystick Interface• Activate/Sleep/

Deactivate

Insert Receiver Picture

Transmitter SoftwareUser Turns on Tag

Initialization

Set CC1000 transmission frequency,

transmission mode

Initialize the uC USART mode and

baud rate

Transmit a square pulse

Transmitter Hardware

• Atmel ATTiny2313

• Chipcon CC1000 Transceiver– Low Current Consumption– Small

• Antennae Design

ATTiny2313

• Larger File Size• SRAM• Watchdog Timer• UART• Small package• SPI

CC1000

• Operating Frequency• Configuration

– SmartRF Studio

Antennae Design

Antennae Design

Antennae Design

Antennae Rx Tx RangeNo Antennae N/A 5~7m

Wire Whip Rx and Tx 4~7m

Helical Wire Rx and Tx 5~8m

Slotted Rx 7m~9m

Slotted Tx and Rx 9m +Trapezoidal Patch Rx 7m~9mTrapezoidal Patch Tx and Rx 9m +

Antennae Design

Antennae Body EffectsNo Antennae Highly Sensitive. Signal periodic

Wire Whip Highly Sensitive. Inaccurate Results.

Helical Wire Highly Sensitive. Signal periodic

Slotted Very Resilient. Consistent quality signal.

Trapezoidal Patch Very Resilient. Consistent quality signal.

ActivateMode

Set K = 0D_ k = 0

D_ k = 1 ?

Poll Tag kperiod ally

Deactivate?

Sleep?

Tag in range

K ++

K = 4

Reactivate ?

BuzzerLight

DeactivateTag I

D_ k = 1

Sleep for 5 minutes

Y

Y

Y

Y

Y

Y

N

N

N

N

N

EnableInterrupts

Set upParameters

Start

Initialization

Rename? Rename Tag

N

N

Y

SelectTag k D_k = 0

K=0

Receiver Hardware

• ATMega32• LINX RXM-900-HP-II• LCD• Joystick

ATMega32L

• Low Current Consumption• RISC Architecture• 32K Flash Memory• 1024 Bytes EEPROM• 3 Counters• Programmable Serial UART• Input Capture• 3 External Interrupts

LINX RXM-900-HP-II

• Programmable Carrier Frequencies

• Direct Serial Interface

• No External RF Components

• No Tuning Required

• Easy Usage

LCD

• Standard Hitachi HD44780 Driver• Small compact size• ~2mA consumption• Command Set

Instruction Code

RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

Clear display 0 0 0 0 0 0 0 0 0 1

Cursor home 0 0 0 0 0 0 0 0 1 *

Entry mode set 0 0 0 0 0 0 0 1 I/D S

Display On/Off control 0 0 0 0 0 0 1 D C B

Cursor/display shift 0 0 0 0 0 1 S/C R/L * *

Function set 0 0 0 0 1 DL N F * *

Set CGRAM address 0 0 0 1 CGRAM address

Set DDRAM address 0 0 1 DDRAM address

Read busy-flag and address counter

0 1 BF CGRAM / DDRAM address

Write to CGRAM or DDRAM 1 0 write data

Read from CGRAM or DDRAM 1 1 read data

Joystick

• Low amounts of board real-estate• Multidirectional Usage• Intuitive User Interface• De-bouncing

Receiver Scheme

• Timer Interrupt Polls

• Receives a Constant Pulse

• Interrupt

• Input Capture

• Checks Pulse Width

• Changes Frequencies

Batteries

• 2032• 2477

• Good Supply Voltage• Low Battery Profile• Reasonable Supply

Curve• mAh

Problems and Solutions

• ATTiny12• Antennas and attenuation• RF Boards – Current Draw• Initialization of the CC1000• Soldering the CC1000• Doesn’t flash with components connected• LCD Initialization failure• LCD Buffer Circuit

Things to Complete/Further Work

• Build multiple transmitters

• Utilize a CDMA scheme to increase resilience to noise and free up channels

• Implement a sleep/watchdog timer

• Minimize package

Budget

Update Budget

Prototype Tx and Rx

CDN $230

Custom Boards

CDN $120

SMD parts

CDN $60

Case

CDN $20

Total CostCDN $530

Personal Reflections

• NEVER try to fabricate your own boards for RF

• Avoid prototyping with surface mounts

• Multiply projected timelines by 4 as opposed to 2

• The best place to crash is the Sunny room

Conclusion

• Good experience taking a project from scratch to close to completion

• Learned to deal with group dynamics

• Sleep is an option not a necessity

Thank You

Questions

References• “Lost and Found.com: The Internet Lost and Found,” [Online Document]

Available: http://www.internetlostandfound.com/• “Lost Property Office - Statistics,” [Online document]

Available: http://www.tfl.gov.uk/tfl/ph_lost-stats.shtml • “Survey: Thousands Leave Laptops, Mobiles in Cabs,” Jan. 24, 2005 [Online document]

Available: http://edition.cnn.com/2005/TECH/ptech/01/24/taxis.lost.reut/index.html• “New Tube Crackdown Puts Pickpockets on the Run,” [Online document]

Available: http://tube.tfl.gov.uk/content/pressreleases/0110/29.asp• “1551KGY” Image. http://www.hammondmfg.com/1551K2B.jpg• Smith, Kent (RFM). “Antennas for Low Power Applications”. Feb 8, 2005. www.rfm.com/corp/appdata/antenna.pdf • “Atmel SOIC” http://sub.chipdoc.ru/im/atmel/avr/2313_p.gif• “Atmel TQFP” http://www.epsilon.com.pl/img/at90s8515_tqfp2b_250.jpg • “TPA Navigation Tact Switch” http://www.ittcannon.com/media/pdf/catalogs/tpa.pdf • “HP Tx and Rx” http://www.linxtechnologies.com/index.php?

section=products&category=rf_modules&subcategory=hp-3_series• “Peter Ouwehand.“How to control a HD44780-based Character-LCD. 2005.

http://home.iae.nl/users/pouweha/lcd/lcd0.shtml • “2032” http://rocky.digikey.com/WebLib/Panasonic/Web%20Photos/CR2032.jpg