team project presentation, april 11, 2007
TRANSCRIPT
Can’tTouchThisK
SM
Ham
mer
Jun Wei ChuahShihong Ng
Ming Yang Koh
Project Concept/Motivation
•Concept: •This project will act as deterrence against laptop thefts, providing the owner a greater degree of security.•The prototype integrates off-the-shelf embedded components, such as motion-sensing accelerometer, buzzer, RFID reader and tags for passive activation of the device and the Tmote Sensor.
•Motivation:•A laptop owner today is unable to leave his/her laptop unattended without risk of the laptop being stolen.•Using our prototype system, an alarm will be activated if the laptop is being handled by unauthorized personnel.
Competitive Analysis:
Caveo Anti-Theft PC Card:http://caveo.com/products/anti-theft.htm
•The product works by sensing motion and emitting an alarm when its moved.•Our product will automatically activate the lock when it does not sense the user’s presence
Kensingstone Cable Lock:http://us.kensington.com/html/11179.html
•The product works by physically locking the laptop to a secure object. •Our product requires less user input and is a smaller and lighter solution.
Requirements:
•Functional Requirements:•Detects the presence of the user when in range and disarms the device.•Arms the device when user is out of range.•Allows software arming and disarming of device.•Detects movement of laptop when armed and sounds alarm accordingly.
•Non-functional Requirements:•Reliability: When armed, the device will detect significant movement and sound the alarm. •Usability: The device will require minimal user input after installation.•Threshold: Non-extended small movements will be tolerated by the system. •Timing: The alarm will trigger within 5 seconds of detection of motion.
Technical Specifications:Microcontroller: Moteiv “Tmote Sky”http://www.moteiv.com/products/tmotesky.php
Buzzer: Generic “Buzzer”http://export.farnell.com/jsp/endecaSearch/partDetail.jsp?sku=1192515
$2.50 ea
Motion sensor: Freescale “MMA7260QT Accelerometer” http://www.freescale.com/files/sensors/doc/data_sheet/MMA7260QT.pdf
$5.68 ea
Rechargeable battery : Generic “3V Rechargeable Lithium Battery”http://www.action-electronics.com/batcomp.htm
Quote pending
Wireless keycard components: RFID Reader: Texas Instruments “Series 2000 Micro Reader RI-STU-MRD1”http://www.ti.com/rfid/docs/manuals/pdfSpecs/RI-STU-MRD1.pdf
Quote pending
RFID Tag: Texas Instruments “Card Transponder TRP-R4FF”http://www.ti.com/rfid/docs/manuals/pdfSpecs/TRP-R4FF.pdfQuote pending
Voltage step-up converter: Texas Instruments “TPS61027”http://focus.ti.com/docs/prod/folders/print/tps61027.html $3.15 ea
Architecture Block Diagram
State Chart for Laptop
State Chart for Microcontroller
State chart for RFID reader
Initreset
On
On
Off
Tag Found
Tag not found
Tag found
Tag not found
Tag fo
und
Tag
no
t fo
und
Initreset
Ringing
Buzzer on
Buzze
r Off
State chart for Buzzer
State chart for Accelerometer
Initreset
On
On
accelerometer
Off
acce
lerom
eter M
otion
sensin
g
List of Use Cases
Bootstrapping
Laptop
Microcontroller
Accelerometer
RFID reader
StartupStartup
Startup
Bootstrapping
TearDown
Laptop
Microcontroller
Accelerometer
RFID reader
Shutdown
TearDown
Shutdown
Shutdown
User leaves laptop User moves laptop
List of Use Cases (continued…)
RFID reader
Tag found
User moves laptop
disarm
RFID tag Microcontroller RFID reader
Tag not found
User leaves laptop
Arm
MicrocontrollerRFID tag
Start motion sensing
Accelerometer
Laptop
Start password screen
Motion sensed
Thief moves laptop
Microcontroller
Accelerometer Buzzer
Start
Laptop
Password entered
Off
Thief moves laptop User approaches
laptop
List of Use Cases (continued…)
RFID reader
Tag found
User approaches laptop
disarm
RFID tag Microcontroller
Laptop
Off password
screen
Risks
R1. Compatibility between RFID reader and Telos Motes R2. Compatibility between voltage regulator, RFID reader and
Telos Motes R3. Compatibility of rechargeable battery with rechargeable
mechanisms on Telos Motes R4. Real-world performance of RFID reader with respect to
range R5. Constraints with respect to the ports available on Telos
Motes R6. Difficulty in finding suitable algorithms differentiating
significant and non-significant movements R7. Usage under different laptop operating environments
Mitigation of Risks
Worst case usage of Zigbee protocol and Telos Motes for passive device (R1, R2, R4)
Requires device to always be plugged into laptop (R3)
Usage of 18-348 board to meet specific port requirements (R5)
Usage of multiplexers to meet port requirements (R5)
For worst case, any slight movement would trigger alarm (R6)
Requires Windows as main Operating System (R7)
Test Cases
Project Concept: Laptop Anti-theft Device Status Update:
Currently working on getting the RFID to communicate with the T-mote (certain voltage issues to sort out)
Desktop interface complete (with password screen) Project Test Cases (Testing the use cases):
Startup (Devices start up without errors) User moves laptop (Nothing should happen) User leaves laptop (Arming of device) Thief moves laptop (Alarm rings) User returns to laptop (Disarming of device) Shutdown (Devices shutdown properly)
Performance Tests Degree of movement
Important to distinguish between subtle movements and theft Test: Various movements around laptop, check correct
identification of theft Response time before buzzer sounds
When theft is detected, important to sound buzzer in a timely manner
Test: Move laptop in armed mode, check that buzzer sounds in no more than 500ms (500ms X 100m/10s = 5m)
Password security Password must be resistant to cracking Test: Look for loopholes in password system (some form of
white-box testing) RFID / Disarming range
User’s presence must be detected from a suitable distance Test: Tester moves into close proximity with the device (no more
than 50cm), check that user’s presence is detected
Testing Process
Usage of checklists for testing Useful for checking degree of movement and RFID range Useful for checking password security
Usage of software tools in testing Software timers for response time calculations (correlate
with hardware timers for accurate timings)
Testing under heavy conditions Testing RFID range in area with several RFID readers or
tags Testing with non-user RFID tags
Looking Ahead
Anticipated Difficulties Ambiguity with regards to significance of
movement RFID functionality still a blur, might switch to
Zigbee modules for authentication Thankfully, most of our test cases are pretty
straightforward Might include testing with errors to ensure
functionality Lessons learnt in testing
As mentioned before, degree of movement test is still rather shady
Difficult for author of code to check correctness (password security)
Questions? Anyone?
Status Update
Project Concept: Laptop Anti-theft Device Status Update (implementation):
Voltage incompatibility of RFID reader, as well as concerns with limited range of RFID
Using Zigbee protocol to communicate between t-motes
Achieved a satisfied level of sensitivity for device Status Update (testing):
Tested varying degrees of movement Tested range of Zigbee protocol
Experimentation plan Metrics:
Range of T-motes Sets distance at which we arm and
disarm the t-mote Degree of movement of accelerometer
Sets the degree movement to trigger off alarm
How to measure Conducted 40 trials for each metric
Measured # times in which device is constantly being armed/disarmed for 5 seconds at a particular distance
Measured # times in which alarm is sounded at the various movements
Initial data Almost every sudden movement
would cause alarm to ring Thief can steal laptop by moving it
away slowly Banging of lab table does not cause
alarm to sound off most of the times
Device will be in disarm mode constantly if user within 1.5 feet
Device will likely be in arm mode constantly if user is at 16 feet from device
% of times device was armed vs distance from device
0%
20%
40%
60%
80%
100%
Range of 1.5 feet Range of 16 feet
Distance from Device
% o
f tim
es d
evic
e w
as
arm
ed fo
r 5 s
econ
ds
% of times alarm sounded vs various degrees of movement
0%
20%
40%
60%
80%
100%
Banging of table (False positive)
Moving laptop aw aysteadily
(False negative)
Sudden movement oflaptop
Various movements
% o
f tim
es it
sou
nded
Looking forward
Lessons learnt: Subtleties in tinyOS,
Deluge library prevented buttons from working Using genericComm instead of which hpluart to send
packets Using Tosmsg->strength instead of Tosmsg->lqi
What is next? Receiving Tosmsg packets from PC Setting and testing with different mote IDs Analyze device for more appropriate sensitivities
to movements and range
Questions? Anyone?