a mobile sensor platform for indoor location-aware navigation by ryan patterson, l3d ura
Post on 20-Dec-2015
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TRANSCRIPT
Existing Technology
• Bluesoft, Inc. Wi-Fi Tags
• Mobile Phone Triangulation
• GPS (Global Positioning Satellites)
Method of Operation
Propagation Speed of Sound:
m/s
320 m/s 1049.6 feet/sec
)15.273(4441.402 Tc
Propagation Speed of RF:
c 2.998•108 m/s
983,571,058 feet/sec
Transmitter Development
3V Power Supply
(‘AA’ Batteries)
Ultrasound Transducers
(Transmitters)
Power Controlle
r
40 KHz High Precision Oscillator
12V, High Power Charge
Pump for Transmission
Transmission Control
Transmitter Development
Orange Trace shows Output to TransducersBlue Trace
shows Oscillator Digital Output
Receiver Development
3V Power Supply
(‘AA’ Batteries)
Third & Fourth Stage Amplification (Variable Gain, up
to 50)
5V Charge Pump for Power Supply
Analog DC
Voltage Converter
Low-Pass Filter (Gain 2), After Second
Stage
Signal Threshold Detection
First & Second Stage Amplification
(Gain 25)
Ultrasound Transducer (Receiver)
Receiver DevelopmentTransducer
Input1st & 2nd Stage
Amp (x25)Low-Pass Filter (x2)
3rd & 4th Stage Amp (x50)
Threshold Detector/Trigger
Amplitude Detection
Transducer Input (~3mV p-p); Transmitter within 5 feet
Attempt of High-Pass Filter
Orange is input; Blue is output
Receiver DevelopmentTransducer
Input1st & 2nd Stage
Amp (x25)Low-Pass Filter (x2)
3rd & 4th Stage Amp (x50)
Threshold Detector/Trigger
Amplitude Detection
Low-Pass Filter, no signal present (only noise); Orange
is input, Blue is output
Low-Pass Filter, weak signal present; Orange is
input, Blue is output
Receiver DevelopmentTransducer
Input1st & 2nd Stage
Amp (x25)Low-Pass Filter (x2)
3rd & 4th Stage Amp (x50)
Threshold Detector/Trigger
Amplitude Detection
Low-Pass Filter, weak signal present; Orange is
input, Blue is output
Output to microcontroller upon detection of signal
Receiver DevelopmentTransducer
Input1st & 2nd Stage
Amp (x25)Low-Pass Filter (x2)
3rd & 4th Stage Amp (x50)
Threshold Detector/Trigger
Amplitude Detection
4th Stage output; No signal (only noise); Full gain (x1250), Magenta is output, Green is trigger Threshold
4th Stage output; No signal (only noise); Attenuated gain (x800), Magenta is output, Green is trigger Threshold
Range TestingDistance (Feet) Receiver Signal Amplitude (V)
10 2.48 (Saturated)
20 2.48 (Saturated)
30 2.1
40 1.5
50 0.8
60 0.2
70 0.1
80 0.04
Amplitude as a function of Distance
0
0.5
1
1.5
2
2.5
3
10 20 30 40 50 60 70 80
Distange (Feet)
Am
pli
tud
e (
V)
Transmitter in windowsill