Transcript Wild Life Audio Sensing

Wild Life Audio Sensing
ECE 445, Fall 2016
Group 33: Daniel Gunawan, Piotr Lukasiewicz
Mentor: Long Le
TA: Yuchen He
Introduction
• An audio sensing and recording system that records animal sounds
• Record animal sounds up to 8 kHz
• Detect sound long lasting
• Provide hardware for mentor’s software
• Implement more sophisticated programs as desired
Objectives
• An audio sensing system that lasts for at least 30 days
• System continuously in ‘on’ condition
• Powered by one or two D-cell batteries
• Only record sounds when detects animal sounds
• Otherwise, system in idle to save energy
System / Product Package
Design Modules
MCU
(Main Control Unit)
Controls system, receives data, records audio
Sensors
Captures audio, filters signal, sends signal to MCU
Power
Provides power to MCU and Sensor modules, protects battery,
.and regulates voltage supply
Design
Diagram
Sensor
Microphone
• Sparkfun Electret Microphone with preamp
• Capture audio
• Transmit analog signal to MCU
Sensor
Low-Pass Filter
• Cut off sound above 8,000 Hz frequency
• -3dB cut off occurs at specified frequency threshold
Sensor
Low-Pass Filter
Sensor
Low-Pass Filter
Bench Test Result
1
0.5
0
Db
-0.5
0
1000
2000
3000
4000
5000
-1
-1.5
-2
-2.5
-3
-3.5
Freq (Hz)
6000
7000
8000
9000
10000
MCU
Microprocessor
• Arduino Pro Mini 328 - 3.3V/8MHz
• Receive analog audio signal from Sensor module
• ADC (Analog to Digital Converter) converts analog signal to digital
• Program decides whether to record captured audio
• MCU conserves power by remaining in idle mode or not recording
• Audio recorded to SD card through interface
MCU
Microprocessor & SD Card Breakout
MCU
Testing & Result
• Test MCU and Sensors together
• Connect microphone, Arduino, and SD interface together
• Run basic sound detect and record program
• Open .Wav file on computer, and check if correct
Power
Overview
• Battery supplies power
• Undervoltage Lockout (UVLO) protects battery
• Boost Converter / Voltage regulator takes input battery voltage,
boosts it to 3.3 volts
• Battery charger charges one battery at a time, separate from system
Power
Block Diagram
Power
UVLO
• Receives voltage input from battery ranging from 2.5 to 1.9 volts
• Must cut off battery when battery voltage drops to around 2 volts
• Protects battery from damage
• Output matches input from 2+ volts, below output is 0
Power
UVLO
Power
UVLO
Simulation
Power
UVLO
Power
Bench Test
UVLO
Input (V)
Output (V)
2.399
2.399
2.350
2.350
2.300
2.299
2.250
2.250
2.200
2.200
2.150
2.149
2.100
2.100
2.050
2.049
2.00
2.000
1.99
0.036
1.95
0.036
1.90
0.036
1.85
0.036
1.80
0.038
Power Voltage Regulator
• Receives input voltage from 2.5 to 1.9 volts
• Boosts output voltage to 3.3 Volts
• SM and MCU require 3.3 volt power supply to function
• Must provide at least 46 mA to SM and MCU, as calculated earlier
• Must provide 3.3 volts
Power Voltage Regulator
Bench Test Result
Input Voltage (V)
Output Voltage (V)
Output Current (mA)
2.4
3.348
109.1
2.3
3.345
107.9
2.2
3.342
106.5
2.1
3.341
104.8
2.0
3.337
102.3
1.9
3.337
101.6
Power
Charger
• Charges one NiMH cell battery
• Separate from system, requires 5 volt supply
• Must provide at least 10 mA threshold current
Power
Charger
Bench test Result
Condition
Current through battery (A)
‘off’
2.364
‘on’
2.405
Differences
0.041
• When the system records sound, 10 mA threshold is required.
• Since 41 mA > 10 mA, the battery will be charged sufficient rate.
Power
Images
Rechargeable
NIMH battery
Charger
Boost converter /
voltage regulator
UVLO
Mentor Program Implementation
Processing algorithms can be organized into three subtasks:
• event detection
• event tracking
• logging / transmitting of audio events
The average possibilities of these 3 subtasks:
Event detection
10%
Event tracking
5%
Logging / transmitting of audio events
85%
Power Consumption
Parts
Power
Consumption
Symbol
Event detection:
0.1 (W+A+T) + 0.8 (A+T) + 0.1 (I+T) =
9.59 mA
audio processing
MIC
0.2 - 0.5 mA
OPA344 (Preamp)
0.3 mA
12-bit ADC
(on Microprocessor)
0.5 mA
Total
1.0 mA
Event tracking:
0.8 (A+T) + 0.2 (I+T) = 5.18 mA
T
uC module
Arduino Pro Mini
(active)
5 mA
A
Arduino Pro Mini
(idle)
0.9 mA
I
other
Writing to SD card
40 mA
W
Logging / transmitting of audio events
0.6 (A+T) + 0.4 (I+T) = 4.36 mA
Estimated average power consumption:
10% (9.59) + 5% (5.18) + 85% (4.36) =
4.924 mA
Conclusion
• Sensor and power tested and verified
• System will record when it detects sound
• MCU works as intended, recording audio to SD card
• Hardware can be used as Mentor desires
• Essentially blank slate for programs
• Future work: implement mentor’s codes to the Arduino