ECE 256Wireless Network Communications

Pulse Event Targeting/Detection

Scott CovertJacob Cox

ECE 256Project Presentati on

ECE 256Wireless Network Communications

Outline

• Objective• Project Overview and Concept• Design• Work Completed• Challenges• Lessons Learned

ECE 256Wireless Network Communications

Objective• Develop a multihop wireless sensor network capable

of detecting sound and signaling base with a noise level and time of arrival (TOA). Use these values to triangulate the location of a one-time event.– Detect, Record, Multihop, Evaluate Data

ECE 256Wireless Network Communications

Tools

Leds

User Button

MicrophoneLight sensor

Reset Charging Indicator

Speaker

The Keychain Alarm...a 130db alarm One 12 volt battery included.

• CYGWIN• TinyOS• NesC

• MATLAB

ECE 256Wireless Network Communications

Multihop Wireless Sensor Network

ECE 256Wireless Network Communications

The Program

Cygwin

TinyOS NesCMake

Config. Module .H

IMAGE

ECE 256Wireless Network Communications

Main

MicDetectM

MicDriverlC

LedsC

VrcVrg

MicThreshold

MultiHopC

TimerMilliC()StdTimerC

MicInterupt

Microphone

MicControl(main)

DelugeC

SendInte

rcept

Rout

eSta

tistics

Rout

eCon

trol

StdC

ontro

l

StdControl

StdC

ontro

lStdControl

Split

Cont

rol

StdContro

l

Comm

StdControl

StdControl

StdTimer

RecordTimerMilliTimerMilliC() RecordTimerMilliC

Configuration

ECE 256Wireless Network Communications

Durham County Wildlife Club

ECE 256Wireless Network Communications

Durham County Wildlife Club

X3, y3X2, y2

X0, y0

X1, y1

a

b

ECE 256Wireless Network Communications

dBA Levels (Problem Discovered)

A = 20*log10(V2/V1) (dB)

http://www.mogami.com/e/cad/db.htmlSilex Sound Attenuation White Paper

Sound Tmote Output

One Meter 130 dB

4095

Car 80 dB

4095

Clap (1-10 Meter) 65 dB

4095

Whisper 20 dB 2900-3500

ECE 256Wireless Network Communications

Low dB Calibration

2800 3000 3200 3400 3600 3800 40000

10

20

30

40

50

60

70f(x) = 117.977188463172 ln(x) − 904.859808579803R² = 0.751086604957344

Calibration Data

ADC Reading (mV)

So

un

d L

evel

(d

B)

ADC to Decibel ConversionsADC Reading Decibel Level

2923 30

3251 60

3851 65

ECE 256Wireless Network Communications

Experimental ResultsLow dB Experimental Results

MOTE TOA SOA (ADC-mV) SOA (dB)1 27.344 3307 51.22592 27.344 3471 56.93633 27.297 3487 57.4789

TOA is Time of Arrival. SOA is Sound of Arrival. dB is the Decibel value of Sound.

Radius Ratio of motes 1 and 2 = 1.93 Radius Ratio of motes 1 and 3 = 2.05Mote 1 event distance: R1 = 1.93Mote 2 event distance: R2 = 1Mote 3 event distance: R3 = .94

Actual Distances were all 2.5 M.Error of 23% to 62%

x

ECE 256Wireless Network Communications

Challenges

• Tmote Invent Variability– Wind Sensitivity, Poor Quality Sensors

• New Programming Language & OS– NesC and TinyOS Learning Curve– Compile Times * time * time …

• Converting to Decibel– Clipping: 4095 (assumed mV) value as ceiling

ECE 256Wireless Network Communications

Lessons Learned

• Acoustic Event Targeting– Sensitive to equipment variability– Look for equipment with self-diagnostics

• Push to improve our programming skills• ECE 256 is Cool!