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Data Storage and Interaction using Magnetized Fabric
Justin Chan Shyam Gollakota
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PROJECT JACQUARD LILYPAD ARDUINO
Existing approaches Requires batteries
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Data Storage and Interaction using Magnetized Fabric Justin Chan - - PowerPoint PPT Presentation
Data Storage and Interaction using Magnetized Fabric Justin Chan - - PowerPoint PPT Presentation
Data Storage and Interaction using Magnetized Fabric Justin Chan Shyam Gollakota 1 Existing approaches PROJECT JACQUARD LILYPAD ARDUINO Requires batteries 2 Can we create a smart fabric design without any onboard electronics or
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Can we create a smart fabric design without any onboard electronics or batteries?
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WATERPROOF BATTERY-FREE
Smart fabrics without electronics
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CODES IMAGES Clothes with memory
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Interact with a smartphone in your pocket
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What are conductive threads used for?
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Key Observation
Leverage magnetic properties of conductive thread
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Smartphones have magnetometers
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Our Contributions
- First to harness the magnetic properties
- f conductive fabric for interaction
- Provide a detailed characterization of
magnetized fabric
- Build electronic-free data storage and
gesture recognition applications on fabric
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Characterization of magnetized fabric
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What do we care about?
- Embroidery style
- Decay over distance
- Decay over time
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20 40 60 80 100 1 2 3 4 5 6 7 8 Magnetic field strength (T) Noise Floor
Magnetic field strength (µT)
20 40 60 80 100
How does embroidery style afgect fjeld strength?
Denser styles have higher fjeld strength
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2.5cm
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How does fjeld strength decay over distance?
Works up to distances of 1 cm
10 20 30 40 50 60 5 10 15 20 Magnetic field strength (T) Distance from phone (mm) 2.5cm2 2.0cm2 1.5cm2
10 20 30 40 60 50 Magnetic field strength (µT) Distance from magnetometer (mm)
5 10 15 20
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10 20 30 40 50 60 1 2 3 4 5 6 Magnetic field strength (T) Days 2.5cm2 2.0cm2 1.5cm2
1 2 3 4 5 6 10 20 30 40 50 60
Magnetic field strength (µT)
Days
2.5cm2 2.0cm2 1.5cm2
How does fjeld strength decay over time?
28-36% decrease over a week
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Remagnetized
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GESTURE RECOGNITION EMBEDDING INVISIBLE IMAGES DATA STORAGE
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Unreadable on smartphones How do we tag clothing?
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> $500-$2000
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Reading and writing codes
Magnetometer
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5mm Guard band 2cm 1cm < $0.17
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Reading the tag on a smartphone
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Change in fjeld strength Hand wash 11% Machine wash 5% Drying 9% Ironing (160°C) 1%
How durable are our tags?
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Are our tags reprogrammable?
No degradation in fjeld strength
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5 10 15 20 25 30 35 40 45 1 2 3 4 5 6 7 8 9 10 Magnetic field strength (T) Tag ID Number
Magnetic field strength (µT)
1 2 3 4 5 6 7 8 9 10
Number of new magnetic codes
10 20 30 40
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Fashion accessories with memory
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EMBEDDING INVISIBLE IMAGES
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ENCODING DECODING
Drawing and reading images
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Magnetic fjeld strength (µT) 60 40 20
- 20
- 40
- 60
1.8cm 9cm
How small can each pixel be?
Smallest pixel size: 1.8 cm2
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9cm 9cm
Expressivity of images
225 ≈ 33 million possible images
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GESTURE RECOGNITION
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Smartphones in pockets
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Low-power IoT devices Power: 72µW Magnetometer Cost: $0.80
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Recognizing gestures
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X Y Z X Y Z X Y Z X Y Z X Y Z
X Y Z
UP LEFT CLICK BACK CLICK DOWN RIGHT
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Real time classifjer
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Actual Gesture Performed Gesture Classified 0.06 0.02 0.04 0.86 0.03 0.01 0.01 0.01 0.92 0.02 0.02 0.04 0.94 0.02 0.01 0.03 0.87 0.06 0.02 0.01 0.9 0.02 0.03 0.03 0.01 0.91 0.01 0.01 0.04 0.03 Back Click Click Right Left Down Up Up Down Left Right Click Back Click Not seen
Classifjer accuracy
7 users 20 repetitions 90.1% accuracy
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Custom designed textiles + a precise magnetic reader and writer
- Generate stronger fjelds
- Increase bit density
- Longer bit lifespan
How do we improve this?
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Conclusions
- Harness the magnetic properties of
conductive fabric for interaction
- Provide a detailed characterization of
magnetized fabric
- Build electronic-free data storage and
gesture recognition applications on fabric
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