Transcript Midway Design Review

Midway Design Review
Team Vibraid
November 2013
Michael Balanov
(Mike) EE
Reona Otsuka
(Leo) EE
Vibraid
Spyridon Baltsavias
(Spiros) EE
Andrew Woo
(Andy) EE
Assistive technology for the deaf community
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Fact: Over 5% of the world’s population – 360 million people – has disabling hearing loss
Deaf/hard of hearing people have limited awareness of surroundings
High demand but production of hearing aids meets only 10% of global need
Currently deaf people have to use specific aids for different applications
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Expensive
Impractical
Vibraid: Vibration + Hearing Aid
• Convert sound to vibration
• Research shows haptic feedback usefulness
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Lip-reading, frequency detection
• Alert user of impending danger/sound source
• Enable tactile sound localization
Physical Design
• Waist Belt
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Intuitive polar representation
Horizontal orientation
Relatively minimum obstruction
Requirements Table
Specification
Value
Circumference
75-105cm (small-large)
Width
<10cm
Thickness
<2cm
Weight
<1kg
Previous Block Diagram
Revised Block Diagram
MDR Focus
4
4
4
8
4
4
variable
resistance
switch signal
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Main changes:
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No Arduino – hardware implementation
Filtering
No light output
variable
resistance
MDR Deliverables
• PDR proposal: Sound to Vibration & Light
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Demo time!
• Additional Deliverables: progress towards 2-way directionality
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Input Block:
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Andy: Microphone requirement testing
Spiros: Envelope Detector design
Processing & Motor Block
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Mike: Comparator logic & motor activation
Leo: Sensitivity logic & DC voltage testing
Input Block
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Purpose:
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Record sufficient sound data
Specification
Value
Pass it on for processing in a format suitable for
amplitude comparison
Detection
Directionality
4 directions
Detection frequency
range
100Hz to 10kHz, 90%
of time
Detection radius for
50dB-120dB sound
within frequency
range
>3m (10ft), 90% of
time
Microphone characteristics:
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4 omnidirectional microphones (Freetronics.com)
Vendor provided frequency response: 60Hz to
15kHz
2 outputs
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Requirements Table
AC audio voltage
“SPL” output DC voltage proportional to amplitude
Mics placed in 4 locations (right/0°, front/90°,
left/180°, back/270°)
Microphone Range Test (Voltages)
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Procedure:
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Measure “SPL” voltage of noise
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Range: 0.00V-0.08V, depending on environment
Measure “SPL” voltage of test-sound
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Computer-generated 440Hz tone
Sound directed towards front of microphone
Sound level from 3ft away: ~70dB (measured with dB meter application)
Determine maximum range for which voltage>noise+0.1V
Average Results:
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10ft detection: yes
15ft detection: no
Microphone Frequency Response
SPL Voltage Vs Frequency
2
1.8
1.6
SPL Voltage (V)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
2000
4000
6000
8000
Frequency (Hz)
10000
12000
14000
Microphone Sound Detection Test
(2 microphones)
Mic A
Radius R
15 in
Mic B
Corresponding angle for each microphone
90/270
135/315
Mic A
45/225
0/180
180/0
Mic B
225/45
270/90
315/135
Degree relative to Mic A/
Degree relative to Mic B
Mic SPL Voltage Reading for various angles
R = 10 inches
Mic #/Degree 0
45
90
135
180
1
0.33
1.49
2.82
1.36
2
1.61
1.47
2.23
3
1.22
1.52
2.87
4
1.52
225
270
315
0.88 1.40
1.01
1.39
1.83
1.30
0.85
1.41
1.31
1.47
1.06
1.52
1.34
1.28
1.52
2.42 1.60
0.83
0.53
1.21
0.88
Mic #/Degree 0
45
90
135
180
225
270
315
1
1.52
0.88 1.60
1.09
0.15
0.52
0.10
0.24
2
1.46
0.70
1.96
0.81
0.83
1.45
1.44
1.28
3
0.50
1.16
1.79
1.60
1.13
0.86 0.79
1.08
4
0.48 0.40 1.57
R = 15 inches
0.69 0.05
1.18
0.08 0.41
Example Mic comparison
Radius = 10 inches
2.87/1.21
(1)
1.47/0.88
(1)
1.06/1.52
Mic 1
(1)
(2)
(1)
(1)/(2)
1.52/1.52
(#) = Stronger Mic at
1.52/0.53 given location
Mic 2
(2)
1.34/2.42
1.22/0.83
(2)
1.28/1.60
Voltage output of Mic 1/
Voltage output of Mic 2
Test Conclusion and Evaluation
• Inconsistency across each microphone
• Unexpected spikes/drops of voltage in some angles
• Microphones are not completely omni-directional
• No simple relationship between distance and sound
amplitude
• Consider directional microphones
Input Block pt.2
• “SPL” output
Envelope Detector Design
Input – DC Block – Amplification
Amplification – Rectification– Smoothing
Processing Block
• Purpose:
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Receive sensitivity knob input to determine if
microphone input should be received
Receive microphone output in order to
compare amplitudes
Determine quadrant of incoming sound
Produce output signal with motor activation
information to be read by Output Block
Requirements Table
Specification
Value
Vibration
Directionality
Simultaneous
vibration in 2 adjacent
locations
Vibration response
time
<o.5sec
Processing Block Circuit
Comparator/Sensitivity Logic
DC testing
Input 1 (V) Input 2
(V)
Output
(V)
0.02
0.02
-0.91
0.02
2.43
-0.91
0.02
4.91
-0.91
2.43
0.02
4.33
2.43
2.43
-0.91
2.43
4.91
-0.93
4.91
0.02
4.33
4.91
2.4
4.33
4.91
4.91
-0.92
Output Block
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Purpose:
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Receives control signals from Processing block
Activates motors in appropriate location
Indicates relative sound amplitude
Motor characteristics
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“Coin” vibration motors, used in cellphones
Noticeable vibration on skin
Small voltage rating
2 motors per key location (front, back, sides)
Requirements Table
Specification
Value
Vibration
Directionality
Simultaneous
vibration in 2 adjacent
locations
Vibration to
corresponding
detection
99% of times
Vibration response
time
<o.5sec
Output Block Circuit
Input 1 (V)
Input 2 (V)
-0.91
-0.91
4.33
4.33
-0.91
4.33
-0.91
4.33
NAND output (V)
4.75
4.83
4.82
0.00
Inverter output (V)
0.01
0.01
0.01
4.91
Interface Block
• Purpose:
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Allow user customization for three features
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Microphone sensitivity
• Adjusts the threshold voltage for comparator block
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Frequency range detection
• Switches between 3 frequency filters and bypass
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Motor strength
• Modifies the motors strength according to user
preference b
• Method
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Potientiometers for tunable voltage divider
Switch to disconnect and reconnect to desired
circuit
Requirements Table
Specification
Value
Tunable sensitivity
Block-all till pass-all
Tunable frequency
detection
4 modes: full range,
100Hz to 4kHz, 4kHz
to 7kHz, 7kHz to
10kHz
Tunable motor
strength
No vibration (0V) to
Max supply (5V)
Output and Interface Potentiometers
Microphone sensitivity
Motor strength
Summary of Requirements
Specification
Value
Belt circumference
75-105cm (small-large)
Belt width
<10cm
Belt thickness
<2cm
Product weight
<1kg
Detection directionality
4 directions
Detection frequency range
100Hz to 10kHz, 90% of time
Detection radius for 50dB-120dB sound within frequency
range
>3m (10ft), 90% of time
Vibration response time
<o.5sec
Vibration directionality
Simultaneous vibration in 2 adjacent locations
Vibration to corresponding detection
99% of times
Vibration response time
<o.5sec
Tunable sensitivity
Block-all till pass-all
Tunable frequency detection
4 modes: full range, 100Hz to 4kHz, 4kHz to 7kHz, 7kHz to
10kHz
Tunable motor strength
No vibration (0V) to Max supply (5V)
Gantt chart
CDR Deliverables
• Goal: Demonstrate 4-way detection and vibration directionality
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Correct quadrant determination
Meet range, frequency specs
Implement working user interface
Prototype filter
Implement levels of motor activation
Portable power supply
Q&A
Power Specifications
Preliminary Cost Analysis
Pros and Cons of Design
• Pros
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Intuitive polar representation
Horizontal orientation
Adjustable
• Cons
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User may need to tuck in their shirt
Hand/clothing obstruction
"SPL" Voltage vs. Distance
3
SPL Voltage (V)
2.5
2
1.5
75dB voice, matching freq.
1
70dB tone, 440Hz
0.5
0
0
2
4
6
8
Distance (ft)
10
12
14
16