Can’tTouchThisK

SM

Ham

mer

Jun Wei ChuahShihong Ng

Ming Yang Koh

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?