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
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
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
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