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Center for Wearable Sensors
A Jacobs School of Engineering Agile Center
Joseph Wang, DirectorPatrick Mercier, Co-Director
Wearables: an exciting high-growth market
Source: Transparency Market Research
Industrial
Infotainment
Fitness
Medical
3 billion wearables
shipped by 2025*
*IDTechEx 2015 Report
Why aren’t we there now?
3
Our Mission:
Address these issues through innovative cross-disciplinary research
Battery Life:
Need ultra-low-power
and/or energy harvesting to
minimize re-charging
Utility:
Need to develop sensors
that are actually useful
Size & Usability:
Need to develop sensors
that are small & seamlessly
integrated into daily life
Why UCSD:
Our Defining Unique Capabilities
4
Ultra-low-power
bioelectronicse.g., world-record lowest-power
wireless biosensors (<1nW)
New & unique
wearable biosensorse.g., non-invasive electrochemical
glucose sensors
Best-in-class
bioenergy harvestinge.g., biofuel cells operating from
human perspirationLED “OFF” LED “ON”
Watch “OFF” Watch “ON”
A B
C
LED “OFF” LED “ON”
Anatomically
compliant electronicse.g., flexible & stretchable sensors
Why San Diego?
San Diego is a hub for wireless and biotech
UCSD is top-ranked in:Engineering | Medicine | Visual Arts & Design
5
We already have the right mix of ingredients…
Let’s take wearable technologies to the next level
Center Research Structure
New sensor
technologies (e.g., electrochemical
sensors)
New fabrication and
integration technologies (e.g., flexible electronics)
Ultra-low-power
bioelectronics(e.g., sub-nW front-ends)
Bio-energy
harvesting(e.g., glucose
biofuel cells)
Demonstration of novel
energy-autonomous
sensor systems
Data fusion &
machine learning
R&D: Jacobs School of Engineering (ECE, Nano, Bio, CSE)
Validation of utility: School of Medicine, VA Hospital, Scripps, Salk Institute, etc.
Social acceptance: Department of Visual Arts
Core
research
thrusts
Enabling
platform
technologies
Deliverables
F O U N D A T I O N
Trained students
in this area
Nano-
engineering
School of
Medicine
Visual
Arts
Interdisciplinary collaborative structure
7
Electrical
Engineering
Bio
Engineering
Computer
Science
Qualcomm
Institute
Institute for
Engineering
in Medicine
Center for
Wireless
Comms.
Design Lab/
CogSci
Jacobs School
of Engineering
Centers and
Institutes
Departments
and Schools
Grand Challenges
NON-INVASIVE LAB-ON-A-BODY
SELF-POWERED SENSORS
NANO-PHARMACY ON-A-CHIP
SELF-PROPELLED
MICROLABS•Photovoltaic
•Thermoelectric
•Battery
•Biofuel Cell
•Integrated epidermal
energy harvesting
Strain
ECG
pH/Na+/K+
Alcohol
Lactate
Glucose
Detailed diagnostics
and drug delivery
under the skin
Micromachine-based platforms
Representative CWS project:A wireless (saliva) sensor in a mouthguard
Health applications
9
Size can be further
DECREASED
with more integration
Fitness applicationsMeasure Lactic Acid for
Stress / Exertion
Measures Uric Acid for Hyperuricemia
J. Kim, S. Imani, W. R. de Araujo, J. Warchall, G. Valdés-Ramírez, T. R.L.C. Paixão, P.P. Mercier, J. Wang, “Wearable
salivary uric acid mouthguard biosensor with integrated wireless electronics,” Biosensors & Bioelectronics, 2015.
Representative CWS project:
Harvesting energy from sweat
Lactate
Pyruvate O2
H2O
A
B C
LED “OFF” LED “ON”
Watch “OFF” Watch “ON”
A B
C
LED “OFF” LED “ON”
J. Wenzhao, X. Wang, S. Imani, A.J. Bandodkar, J. Ramirez, P.P. Mercier, J. Wang, “Wearable textiles
biofuel cells for powering electronics,”Journal of Materials Chemistry A, 2, pp. 18184-18189, 2014.
CWS: a world leader in glucose sensing
11
Non-invasive
glucose tattoo
Implantable
glucose monitor
Directions: Paintable Glucose Sensors
CWS: a world leader in soft electronics
12
Building systems that comply with
smooth curvilinear human anatomy
CWS: a world leader in non-contact
electrophysiological sensing
EEG alpha and eye blink activity recorded
on the occipital lobe over haired skull
ECG Motion Compensation
Enabled through hardware/
software co-optimizations
EEG Through Hair
Walking
Sitting
J.-H. Lin, H. Liu, C.-H. Liu, P. Lam, G.-Y. Pan, H. Zhaung, I. Kang, P.P. Mercier, C.-K. Cheng, “An Interdigitated Non-Contact ECG
Electrode for Impedance Compensation and Signal Restoration,” in Proc. IEEE Biomedical Circuits and Systems Conference, Oct. 2015.
Chi, Y.M.; Yu-Te Wang; Yijun Wang; Maier, C.; Tzyy-Ping Jung; Cauwenberghs, G., "Dry and Noncontact EEG Sensors for Mobile Brain–
Computer Interfaces," in Neural Systems and Rehabilitation Engineering, IEEE Transactions on , vol.20, no.2, pp.228-235, March 2012.
Low-power body area networks
14
Conventional e-field
human body
communications (eHBC)
Proposed magnetic field human
body communications (mHBC)
Upwards of 70dB improved path loss
compared to Bluetooth
J. Park and P.P. Mercier, “Magnetic Human Body Communication,” in Proc. IEEE Engineering in Medicine and Biology Conference (EMBC), Aug. 2015.
Why aren’t we there now?
15
Our Mission:
Address these issues through innovative cross-disciplinary research
Battery Life:
Need ultra-low-power
and/or energy harvesting to
minimize re-charging
Utility:
Need to develop sensors
that are actually useful
Size & Usability:
Need to develop sensors
that are small & seamlessly
integrated into daily life
Harvesting energy from the human body
16
Respiration (~100nW)
(U. Wisconsin-Madison)
Nanogenerator (~1mW)
(Georgia Tech)
Leg motion (~10W)
(Bionic Power)
Biofuel cell (~100μW)
(UCSD)
Heel strike (~1W)
(MIT)Thermoelectric (~100μW)
(MIT)
Lactate
Pyruvate O2
H2O
A
B C
A (New) energy harvesting source:
inside the inner-ear
17
Challenge: anatomically-miniaturized electrodes
limit extractable power to ~2nW
Yes we can!Chip implementation details:
18
Technology 0.18 µm CMOS
Supply 0.8 - 1.1 V
Charge-pump 1.4 - 2.2 V
Radio data rate 0.1 - 10 Mbps
Chip-on board small enough to
fit in the human mastoid cavityP.P. Mercier, A.C Lysaght, S. Bandyopadhyay, A.P. Chandrakasan, and K.M. Stankovic, “Energy extraction from the
biologic battery in the inner ear,” Nature Biotechnology (Cover Article), vol. 30, no. 12, pp 1240-1243, Dec. 2012.
Endoelectronics chip:
EP harvester architecture
VINVEP
P.P. Mercier, A.C Lysaght, S. Bandyopadhyay, A.P. Chandrakasan, and K.M. Stankovic, “Energy extraction from the
biologic battery in the inner ear,” Nature Biotechnology (Cover Article), vol. 30, no. 12, pp 1240-1243, Dec. 2012.
Transmitter duty-cycled power
comparison
20
Average power @ 1 packet/min: 78 pW
62 pJ/bit
P.P. Mercier, S. Bandyopadhyay, A.C. Lysaght, K.M. Stankovic, A.P. Chandrakasan, “A Sub-nW 2.4 GHz Transmitter for Low Data-Rate Sensing Applications,” IEEE
Journal of Solid-State Circuits (JSSC), vol.49, no.7, pp.1463-1474, July 2014.
Clinical guinea pig experiments - setup
21
Surgery performed by Andrew
Lysaght at the Massachusetts
Eye and Ear Infirmary
(not to scale)
High-impedance
multimeter
(to measure VDD)
Clinical guinea pig experiments - results
22
First demonstration of an electronic system sustaining
itself from a mammalian electrochemical potential!
Wireless start-up Self-sustaining supply
P.P. Mercier, A.C Lysaght, S. Bandyopadhyay, A.P. Chandrakasan, and K.M. Stankovic, “Energy extraction from the
biologic battery in the inner ear,” Nature Biotechnology (Cover Article), vol. 30, no. 12, pp 1240-1243, Dec. 2012.
Applications this can enable:
slowly-varying bio systems
• Do not require rapid sensing
• Suitable for energy-buffering architectures
• Possible to source energy & sense at the same time
Temperature Hydration/lactate Blood sugarGlobal dopamine
concentrations
Energy harvesting directions
24
Ambient RF
Blood pressure
Low-leakage electronics and
energy buffering architectures
can make intermittent energy
harvesting sources useable in a
wider range of applications
Nanogenerator implant
(Georgia Tech)
0.1 W – 1mW
0.1 – 10 mW
? W
Energy storage
Challenge: Security
• Next-generation wearable and IoT applications
will be enabled via ultra-low-power
implementations
• Challenge: how do we secure the data from
these designs at ultra-low-powers?
25
Whoever solves the security problem will win the IoT market
EEMS Lab Acknowledgements
26
