1. NFC-WISP: A Sensing and
Computationally Enhanced Near-Field
RFID Platform
Disney Research, Pittsburgh†
University of Washington‡
Yi (Eve) Zhao†‡, Joshua R. Smith‡, and Alanson P. Sample†

2. Traditional NFC Applications
Secure Payment Access Control
Information RetrievalItem Tracking
2
Tap to
exchange
ID

3. What else we can do with NFC?
3
It’s not only about the ID anymore…

4. Pushing beyond “tap to activate”
User Interfaces
(Antenna modification)
N. Marquardt, etc, “Rethinking RFID:
Awareness and control for
interaction with RFID systems”,
SIGCHI ’2010. 4
Battery-free
human-to-computer
interaction device

5. Pushing beyond “tap to activate”
Implantable Sensing－
Glucose monitoring
(Fully custom ASIC)
A. Dehennis, etc, “A Near-Field-Communication (NFC)
Enabled Wireless Fluorimeter for Fully Implantable
Biosensing Applications,” IEEE International Solid-State
Circuits Conference, 2013
5
Sense without
wires and battery
Expensive long
IC design cycles

6. Unique Features of NFC
6
Implanted SensorsUser Interfaces
• Wireless power transfer
• Ultra-low power communication
• Simple architecture & cheap

7. Motivation
• Challenges
For research & fast prototyping
– High barrier to entry
– Expensive custom IC design cycles
7
Researchers
IC Design
• Opportunity
– Ubiquitous handheld readers
– Pervasive NFC tags

8. Motivation
8
Tools to explore next generation of
Near-Field RFID
before IC design
Sensors & Interface
Research area
…

9. NFC-WISP
• Fully programmable
（protocol & application）
• Passive(without battery) /
Semi-passive(battery assistant) /
Active(battery powered)
• Wireless charging
• Design for easy integration of
peripherals and testing
• Build-in Sensors & User interface
• ISO-14443 Type-B protocol
Near-Field Communication - Wireless Identification and Sensing Platform
9

10. • MSP430
Hardware Overview
10
Top
view
• User interface：
Buttons & LEDs
E-ink display
Bottom
view
• Energy Storage：
Ceramic cap
Battery / Super cap
• Header:
ADC , SPI, UART, I2 C
2.5V Supply
Real time clock
Rectified DC voltages
Test points
• Sensor & Memory
3D Accelerometer
2MB FRAM
Thin-Film Li-lon
battery

11. System Architecture
11
ISO 14443 Type B
ISO 14443 Type A
ISO 15393
Rectified
voltage monitor
& Li-ion battery management
Q ≈ 20 Optional

12. Challenge 1: Clock and Data Recovery
• Signal amplitude and Bit-width vary with distance
and load
• 10% AM modulation
Microcontroller
(MSP430)
Low Pass Filter
Low Power Wake Up
High Speed Threshold
Baseband
Downlink
Baseband
Uplink
Data
Wakeup
Modulator Envelope Detection
RFInput
13.56MHz
Crystal
Bit Line
Bit Line Reference

13. Challenge 1: Clock and Data Recovery
• Signal amplitude and Bit-width vary with distance
and load
• 10% AM modulation depth
Envelope of received signal
Bit-line
Bit-line
Reference
Data
“b000..”
Data
“b11”
13

14. Challenge 2: RF bandwidth
Power harvesting efficiency
v.s.
Communication bandwidth
(ISO 14443 Type B require 847.5kHz)
Q=f0f2-f1
14

15. Challenge 3: Power Management
15
MSP430 start up
Rectified
Voltage
（V）
4.2
2.7
1.8
5.6
Item Operation Voltage
Li-ion battery 2.7~4.2 V
E-ink 2.3~3.6 V
MSP430 1.8~3.6 V
Others 2.0~6 V
MSP430 powered off
Max Voltage
Disconnect battery
Connect battery
Regulated voltage
2.5V

16. Challenge 4： Firmware
• Low power
• Software defined NFC
protocol
• Easily extendable
16

17. How about its performance?
17

18. Performance: Reading Distance
Category Mode Reader Type
Tx Power
(mW)
Distance
(cm)
Read
Distance
Passive
TI TRF7970AEVM 200 3
Nexus 5 <200 0.5
Semi-
Passive/Active
TI TRF7970AEVM 200 11.5
Nexus 5 <200 1.2
Limited by
• Up-link （tag to reader）
• Protocol
18

19. Performance: Energy Harvesting
• Limited by
– Antenna design (Q)
– Bandwidth of analog front end
– Max Battery charging current
Category Mode Reader Type
Charging
Current
(mA)
Charge hours for
10mAh battery
(20% loss)
Extra
harvested
current
Sleep mode
TI TRF7970AEVM 4 3
Nexus 5 1.9 6.3
NFC Reading
mode
TI TRF7970AEVM 3.7 3.2
Nexus 5 1.6 7.2
19

20. Category Current/Power Duration
Sleep Mode
(disable FRAM)
9.7uA
Sleep Mode
(Enable FRAM)
12.7uA
Demodulation
(REQB command)
2.6uJ 783uS
Modulation
(ATQB command)
11.4uJ 1.6ms
Single read of Accelerometer 267nJ 45us
Single read of Temperature
sensor (ADC)
369nJ 94us
Temperature sensing and
E-ink updates 1 line
3.6mJ 0.57s
E-ink Update 1 frame 8.4mJ 0.57s
E-ink Update 4 frames 9.72mJ 0.98s
Performance: Energy Consumption
Estimate power
consumption
for your
applications
20

21. NFC-WISP vs.
UHF WISP
Feature NFC-WISP UHF WISP
Physical layer Near-field (13.56MHz) Far-field (915MHz)
Harvestable Power ~10mW ~0.010mW
Reading Range 0.03m 8.0m
Mode Passive or Semi-passive Passive
Protocol ISO 14443 Type B EPC Gen 2 (18000-6c)
MCU MSP430F5310 MSPFR5969
Memory 2MB external FRAM
+ 32KB FLASH + 2k RAM
64K FRAM +
2K SRAM
Feature Ultra low power sensing &
display
Ultra low power sensing
21

22. What can you do with an NFC-WISP?
Lots…
22

23. Application – Display tag
• Secondary screen for smart phone
NFC-WISP with 2.7” E-ink display
• Energy Neutral
• Dense energy storage needed
(battery or super cap)
23
NFC-WISP with 2.0” E-ink display
• Also Energy Neutral
• >300uF
(Without battery or super cap)
Protected
logo
Protected
logo
Protected
logo

24. Does NFC-WISP only work when
tapping onto the reader?
24
No

25. Application – Data logger with
Display for Cold Chain Monitoring
25
Vaccine Food/Drink
…
Transportation

26. Application – Data logger with
Display
Cold Chain Monitoring
Simulation
• NFC-WISP in Active Mode
（with battery）
• Sensing
– Temperature
– Orientation
– Movement state
• Real time display state on
E-ink （without reader）
• Read historical sensing
data with NFC reader
26
Motion

27. A B C D E F G
A: Moving milk box
B: Carry and put it into
fridge
D: Heat box up
E,F: Change orientation
G: Read data with NFC
reader
Temperature & motion logging
27

28. Application – Wireless Charging
Tx Power:
1 Watt
Combine NFC RFID with wireless power
– A4WP (Rezence) (13.56MHz)
– Magnetic coupled resonance
28
Tx Power:
1 Watt

29. NFC-WISP is Open Source!!
• http://nfc-wisp.wikispaces.com/
Wiki & Forums Source Code
(BSD license)
Hardware CAD files
(Schematics, layout & Gerbers)
…as of today
29

30. Future Work
• Dynamically optimize power
harvesting efficiency
• Sensing enhanced cell-phone with
NFC-WISP
• Implement more NFC protocols
• Explore more NFC application
30

31. Thank you & questions?
31

32. Backup slides start
32

33. … and more 33

34. Challenge 3: Power Management
34
5.6
C) Falling Edge: Disconnect Battery
(Passive Operation Only)
B) Rising Edge: Supervisor Enable
(regular & battery controller)
A) Over-Voltage Protection @ 5.6V
D) Falling Edge: Warning
(min voltage for E-ink)
E) Falling Edge: Supervisor Disable
(system power down)
4.2
2.7
2.3
1.8
RectifiedVoltage(V)
Time
Linear
Regulator
(2.5V)
Optional
(Thin Film Battery
or Super Capacitor)
Charge
Controller
Supervisor
Low Voltage
Warning
(2.3V)
NFC-WISP
Digital Core
Voltage
Measurement
Circuit
Full Wave
Rectifier
(3 Stage)
VRegulated
VRectified
Supervisor
Rising – 4.2V
Falling – 1.8V
Enable
VRectified
RFInput

35. 35