Bringing Safety and Security to Battery-less Smart Clothes Shilin - - PowerPoint PPT Presentation

Bringing Safety and Security to Battery-less Smart Clothes

Shilin Zhu Apr 2017

Questions To Be Answered

• Is the current user the secure owner of smart

cloth?

• Is the user having safe interaction with the

environment and other people?

Three Technical Questions

• How to sense the security and safety?
• Wireless, Computer Vision, Electrical, Pressure …
• How to actively react to danger by clothes?
• Display, Physical, Communication …
• How to make the cloth battery-less?
• Energy Harvesting: RF, Solar, Temperature, Motion, …

Is the current user the secure owner of smart cloth?

Distributed Capacitance / Impedance Across Body Motion and Deformation Tracking Sound Pattern Recognition Infrared Emission

Is the user having safe interaction with the environment and people?

Smart Pocket with Capacitance Monitoring and Light Sensing Pre-Collision System Body and External Pressure Monitoring Outdoor Traffic Safety Radiation Absorption (Asymmetric) Disabilities Guide and Track Appearance Adaptation (For Soldiers) Weather Forecasting Space Suit

How is such smart clothes made of?

Smart Conductive Textile Stretchable and Washable Electronics, Sensors and Display Communication Unit with Computing Unit Safety Reaction Components Attachments Tactile Motion Display Report Pressure Power Supply (Passive or Active)

What kind of designs do we need?

Distributed On-Body Capacitance, Shadows and Vital Signs Computing and Action Classification 360 Degree Environmental Learning and Strategy Reliable Cloth-Mobile and Cloth-Attachment Communication (e.g., cloth-watch) Overcome Frequent Interference on Clothes (environment or human) Signal Injection and Extraction on Clothes Sensor Distribution Based on Cloth Dynamics (stretchable, rigid, …)

Customized In-Cloth Smart Tag

Stretchable and Washable Tag

Capacitance Sensing (Similar as LiveTag) Antenna for BackScatter (Unique Frequency Point) OR Active Transceiver

3D Printed Inside Cloth with Conductive Textile Deformation Dependent Response Combined with Phased Array Cloth Dependent Response

Active Sensor Panel (e.g., PD, Sonar) Energy Harvesting Module Safety Reaction Module (e.g., LED, Stretchable Display)

Must do Both Active and Passive Ways

Smart Tag Reader (Frequency Sweeping)

In-Cloth Simple Controller with Energy Harvesting

Controller

Computing Passive for the Body Active for the Environment

Tag Returns Body Information Tag Returns Environment Information

Both Wireless (WiFi, mmWave, Visible Light) and Wired

Controller

Wired Conductive Fabrics Wireless Reader Channel Body Wireless Environment Channel Visible Light Wireless Channel Wireless Attachment Channel

On-Body and On-Cloth Safety and Security Network

Controller

Like a On-Body SDN Highly Connected Light-Weight Tags/Controller Tag Works Both Like an Integrated Sensor and a Router Safe? Safe? Safe? Safe? Safe? Safe? Safe? Safe? Safe? Safe? Secure?

NFC BackScatter

MIMO Patch Antenna NFC Coil Time Multiplexing and Pipelining BackScatter NFC Power Capacitance Sensing Tag No Longer Needed for Passive Sensing Microphone Pocket LED Energy Storage Magnetic Conductor Sensing Ultrasonic Sensor?

More on Pipelining

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Pipeline'Design'

Master/Slave'D'flip9flop,' controlling'module'selec>on'

Security and Safety Oriented Data Analysis

• Capacitance Tag: Body and Motion Monitoring
• Microphone: Human Talk, Car Engine
• MIMO Patch Antenna: Obstacle Detection
• Magnetic Coil: Conductors

Secure? Safe?

Power

• Cloth itself is Battery-less (Harvested from NFC since
• thers are too unreliable)
• Energy Storage System is used for Maintaining Power

Supply (Overcome NFC Coupling Dynamics when Smartphone is in the Pocket)

• Time Slot and Pipelining: Power and Latency Reduction
• We Simplify the Circuits used for Data Receiving (e.g.,

avoid using Micro-controllers) , mW Level (NFC provides W Level)

Two Modes

Active Mode: It works like a Smartphone-Powered Radar and Metal Detector - Safety Whether NFC has the ability to power the entire active system is a question. Passive Mode: It works like a Large Backscatter Device - Safety Environment must emit some signals that can be passively received.

This is still energy harvesting, the smartphone is powering the entire system. I do not know if the system drains the phone’s battery slow or quick. If quick, then it is worse than directly embedding a battery (Smartphone needs to do better things like phone calls).

Why Not Camera for now?

• Cannot be further made stretchable for now
• Need high resolution to do image recognition
• More Power Consuming
• Sending a 8MP image back through NFC is impossible

for safety applications, need to add a video streaming unit

• Won’t work during the night which is very important for

safety applications

Long-Wave Magnetic Field Sensing

Environment Conductive Objects (Object can be Passive) Other Non-Conductive Objects (Object must be Active)

Magnetic MIMO Beamforming: MagMIMO (MobiCom 2014, 1MHz) and MultiSpot (MobiCom 2015, 1MHz)

Existing Magnetic MIMO is Used For Wireless Charging, Not Sensing We also Need to Measure the Relative Motion (Tracking) to Do Classification They are Focusing on Circuits, Not Mag Field Formula

Magnetic Beamforming

Hbeam = ai ⋅e jθi ⋅ xi

{ }

i=1 n

∑

Hcoil ∝ Icoil

Frequency

• Rubee Uses 131 KHz
• Disney Research Uses 360 KHz - 50 m, Single Coil
• MagMIMO and MultiSpot Uses 1 MHz (Wireless

Charging)

Why Long Wave Magnetic Signals?

Behind the Obstacle Especially Steel (RF may get blocked) Ultra Low Power Reasonable For IoT Safety Issues Are Always Hidden Magnetic Field is Safer than Electrical Field Suitable For IoT Safety Apps e.g., Powder MultiPath-Free

Object - Object & Human-Human & Human-Object

3 Modes

Active Half-Active Half-Passive

Do We Need Magnetic Channel Estimation?

M1 M2

α1x

α 2x

Real(α1) Real(α 2) = Img(α1) Img(α 2) = M1 M 2

M1/M2 determined by pre-computation/pre-training, based on object classification? How M1/M2 changes with receivers at same location/angle? 2 Coils:

M1 M 2 = Z1

' − Z1

Z2

' − Z2

Zi

' = Vi / Ii

Simple Sim (Single Coil & a Metal)

Smart Pocket

• RF Solution: In-Pocket Antenna Connected to the

Cloth Antenna (Use WiFi?)

• Magnetic Solution: In-Pocket Magnetic Coil
• 2 Functions:
• Classification: User’s Own Hand OR Stranger’s Hand
• Track Things (Either Conductive Or Non-Conductive)

In the Pocket

Challenges

• Passive Ways are Limited to Conductor, Otherwise Need an Active Mag Tag

Powered by Battery or Energy Harvesting Attached to the Object

• Range, Antenna Size and Shape Dynamics, Magnetic Core
• Poor Directionality Unless MIMO
• Bandwidth is Limited
• Separate Multiple Signals (Multiplexing?)
• Magnetic Signal Modulation (Specific Time-Varying Magnetic Field)
• Receiver Side is Totally Unknown, Making Mutual Inductance Computation Very

Hard (Assume multiple M when Calculation? Beam Scanning Algo?)

• Unpredicted Environment Impact

Magnetic Signal Ad-Hoc Sensing

Tranceiver Passive Conductor Active Mag Tag Max Sensing Range Active Mag Tag & Router Active Mag Tag & Router Pocket Max Safety Range

Power

• Battery (can last for 5-25 years?)
• Energy Harvesting (Indoor: WiFi,

NFC, Magnetic; Outdoor: Solar, NFC, Magnetic

• Battery Fabrication: Flexible

Printed Battery may be Used since RuBee does not Require Much Power One-Time Recharging for Several Years?

Antenna

• Self Magnetic Loop Antenna
• Without Steel Magnetic Core? Should be Easy to

Be Printed

• Make Attached Conductor as Antenna (e.g.,

Human Body, Steel, …)

• How to Sense the Direction of Magnetic Source?

And Distance?

Range

• Limited: Maximum 20 meters (in air, maybe),

Otherwise We need Higher Power?

• Could we Use Multiple Objects to Do Ad-Hoc

Magnetic Transmission (e.g., Act as Routers as well)?

Thanks