April 3rd, 2008

April 3rd, 2008

WIRELESS AUTONOMOUS TRANSDUCER SYSTEMS

Sywert H. Brongersma

Unither Nanomedical & Telemedical Technology

April 3rd, 2008

3© Holst Centre

Holst Centre open innovation

Wireless Autonomous Transducer Solutions

IMEC

System-in-Foil Products and Production

TNO

Technology Integration

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April 3rd, 2008

4© Holst Centre

Medical & Lifestyle as an application driver

Wearability

Connectivity

Intelligence

Functionality

Autonomy

Implantability

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April 3rd, 2008

5© Holst Centre

Optimizing energy scavenging

Camel Fridge: medicine transportation

2mW 0.03mW/cm2

S10W

A10W

FrontEnd

20WDSP

20W

Radio20W

Micropower System - 100W

P20W

Thermal, Vibrational, RF, Light

NonElectrical

World

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6© Holst Centre

Physical sensing or actuating mechanismTransducer design & physics

Device physics inside nanowire,MEMS,…

Signal preconditioning: Amplification, buffering, actuator driving, …

Typically analog electronics

Interface between sensor and signal processing unitTypically ADC, DAC, or counter, pulse generator

Low-level signal processingSensor data calibration, data correction, compression

Transducer feedback and control loop

Algorithms for data interpretationPattern matching, sensor data fusion, classification

Data interpretationApplication software, diagnosis, …

Underlying technology to fabricate transducersMEMS, nanowire deposition, micro-optics, …

Application layer

Algorithmic layer

Processing layer

Interfacing layer

Signal conditioninglayer

Physical layer

Technology layer

Picture: P. Nair (Purdue Univ.)

An Integrated Approach is Key…

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7© Holst Centre

www.continuaalliance.org

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8© Holst Centre

2002: Portable they say…

Progress in ambulatory EEG…

2008

ULP biopotential read-out ASIC

3D-SiP layer integration

Formfactor 300 1 cm3

Low power <10mW

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April 3rd, 2008

9© Holst Centre

[ MIT Technology Review ]

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Patient Number

Se

con

ds

Aft

er E

lect

rog

rap

hic

O

ns

et

Automatic Detections" "Patient/Caregiver Pushbutton"Feature

Extractor

FeatureExtractor

EEG Channel 1

EEG Channel 21

Support-Vector

Machine

EEG Channel 2 ClassificationTemporalConstraint

FeatureExtractor

X1,1

X1,2

X1,3

X1,4

X2,1

X2,2

X2,3

X2,4

X21,1

X21,2

X21,3

X21,4

… to enable automated epileptic seizure detection

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10© Holst Centre

Power Consumption of 8-Channel EEG

Micro0.81mW

Radio2.40mW

EEG0.30mW

Total power consumption: 3.51mW

256 Hz

8 channels

Further reduction towards 100 W

Radio technology

Local processing to reduce transmission

DSP w. > 500 MOPs/mW required

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11© Holst Centre

In parallel: wireless ECG patch

Hybrid integrationElectronics integration on flex substrateTextile integration for stretchability

Flexible core partULP bio-potential read-out front endLow-power digital signal processing: TI MSP430 f1611Low-power radio link: Built on Nordic nRF24L01175mAh Li-ion battery

Band-aid integrationWire-free and easy to set-upFits any body shapes and electrode placement

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12© Holst Centre

Towards automated arrhythmia detection

99.5499.5410010099.9099.9099.90Se(% )

7.903.98-1.18-1.416.4510.8312.06Me (samples)

22.9719.4813.214.4413.9622.6132.33Sd (samples)

3542354236233623319431943194# annotations

TendTpeakQRSendQRSonPendPpeakPonParameters

99.5499.5410010099.9099.9099.90Se(% )

7.903.98-1.18-1.416.4510.8312.06Me (samples)

22.9719.4813.214.4413.9622.6132.33Sd (samples)

3542354236233623319431943194# annotations

TendTpeakQRSendQRSonPendPpeakPonParameters

For 90 nm technology:

DSP Active power consumption 6mW + Duty cycle 1%

Average power consumption 60W

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April 3rd, 2008

13© Holst Centre

And also: body temperature… on flex & SpO2 autonomously

Commercial SpO2 sensor integrated

with WATS sensor node

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14© Holst Centre

Multi sensor node approach very powerful

ECG, respiration

EMG

EEG, EOG

SpO2

Temperature

Activity monitoring

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15© Holst Centre

Multi-sensor body area network for complex health issues

Star network with 3 slaves2 channels EEG (F2/A1 and C2/A1)2 channels EOG1 channel EMG

TDMA MAC protocol

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16© Holst Centre

Wireless Sleep Monitoring

Sleep apnea prevalence

Europe: 4% male population, 2% female population

USA: 10% population

Narcolepsy prevalence 1 in 1359

Dramatic socio-economic consequences

Current sleep monitoring systems

Expensive, non-natural environment

Wired systems: cumbersome, noisy, hinder mobility

Wireless sleep staging system

Pre-screening in home environment

Ambulatory and comfort

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17© Holst Centre

Preliminary clinical evaluation

Unither Nanomedical & Telemedical Technology

April 3rd, 2008

18© Holst Centre

Monitoring emotions

psycho-physiological response to external stimuli

Emotional response

ANS

Homeostasis…

CNS

Control behaviorInfo processing

…

Vocal system

Speech…

Emotional response is one of many reasons for

changes in ANS, CNS and vocal system

Need for integration of multi-modalities

Need to isolate emotion response

Ultra-low-power wireless sensor network

as enabling technology

Test environment

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19© Holst Centre

Application 1: Biofeedback and emotion control

ECG, Respiration

Temperature, GSR

Back muscle stiffness

Emotionclassification

FeedbackVisualAuditivePharmaceutical

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20© Holst Centre

Application 2: monitoring acceptance of drug treatment

Hospital analysis

WB

AN

: U

LP U

WB

for

15.

14a

stan

dard

Net

wor

k (s

ecur

ity,

priv

acy,

rel

iabi

lity)

Continuous monitoring from home

Unither Nanomedical & Telemedical Technology

April 3rd, 2008

21© Holst Centre

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Feature 1

Fea

ture

2

First prototype of emotion monitor

Emotion

Cla

ssifi

er

ECG

GSR

Temp

Respiration

MeanMean 1st diff

MeanMean 1st diff

Mean

MeanMean 1st diff

Emotion

HR + filter

analysis

Filter

Filter

RR + filter

FFT

Cla

ssifi

er

ECG

GSR

Temp

Respiration

MeanMean 1st diff

MeanMean 1st diff

Mean

MeanMean 1st diff

Emotion

HR + filter

analysis

Filter

Filter

RR + filter

FFT

Fisher mapping:

Clustering of emosion

Error rate: ~40%

Interpretation• Error rate estimated using leave-one-out

cross-validation on a very reduced data

set• Risk of over-fitting

Check on new data set !

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April 3rd, 2008

22© Holst Centre

Trend towards the future:

Truly Unobtrusive Monitoring Solutions

with ever increasing sensor functionality

On-board power scavengingLow power sensors & actuators

* Sweat, Saliva, Breath Lactate, Urea, Glucose, Oxygen, Acetone

* Polerized dipole moleculesNO2, CO, Ethanol, Amines

* Redox moleculesAmmonia, NO2, H2S, COx)

* Volatile organic compounds Benzene, Alkanes, Ethanol

read-out circuitry radio dsp