Smart sensor architecture 2006

1 © 2006 Nokia S mart S ensor Architecture.ppt / 2006-03-10 / IJ

Smart Sensor Architecture

Smart Sensor System Architecture in Mimosa project

Iiro Jantunen / Nokia Research Center

Tutorial Ambient Intelligence,

Toulouse, March 10, 2006


Contents

•What is a smart sensor system?

• Transducer, analog electronics, ADC , digital electronics

•Open architecture for smart sensors• BluLite

• Public S S I protocol

• nanoUDP/nanoIP networking

• O pen API:s for developing applications for using smart sensors

•Mimosa architecture for smart sensors• Wired & wireless BluLite or R FID connection

• Many sensors in many devices over many radio technologies


From sensors to smart sensors

S ensor

Active sensor (S T 3-axis accelerometer)Wireless smart sensor

Passive sensor (photodiode)


Smart Sensor Systems

• C ombine functions of sensors and interfaces

• S ensing

• Amplification

• S ignal conditioning

• AD conversion

• Bus interfacing

• Include higher level functions

• S elf-testing

• Auto-calibration

• Data processing and evaluation

• C ontext awareness

• C ommunications

• Modularity and/or integration

• Transducer• physical reality → electrical

measurable

• Amplifier & filtering• sensor impedance, signal strength

and quality

• Analog-digital conversion

• Microcontroller / DS P / AS IC• Digital signal processing

• C ommunications to outside world

• Networking• S erial interface (US B, S PI, MMC )

• R adio interface (optional)


Transducer

• C onverts between physical properties

• The resulting property can be

• E lectrical capacitance

• C urrent

• Voltage

• Optical power

• E lectrical measurand needs an amplifier/filtering circuit to provide electrical power, impedance etc.

• O ptical measurand needs a optoelectrical transducer with the same properties

R eluctance, optoelectronic, ultrasonic, radar

Displacement, position, proximity

Tuned laser & optoelectronic

G as concentration

OptoelectronicR adiation

C apacitiveS ound, pressure

C lock signalTime

G PSLocation

R esistive, capacitiveHumidity

PiezoresistiveForce

Pressure differenceF low

Piezoelectric, capacitiveAcceleration

Typical/common

techniques

Measurement


Non-ideal behavior of sensors

S tore value and correctTemp. dependence of sensitivity

S tore value and correctTemperature dependence of offset

F ilterModifyUnsuitable frequency response

R educe power useIncrease coolingS elf-heating

BufferUnsuitable output impedance

AmplifyIncreaseLow sensibility

AmplifyIncreaseLow resolution

PredictableHysteresis

S tore value and correctC alibrateC ross-sensitivity to temp and strain

R educeNonrepeatability

Auto-rangeTime dependence of sensitivity

Auto-zeroMinimizeTime dependence of offset

C alibrate/reduceC alibrateOffset

C ompensateMinimizeDrift

R educeC onsistentNonlinearity

MC U/DS PS ensor InterfaceS ensor DesignC haracteristic

From R . F rank: Understanding Smart S ensors , 2n ed.,


Amplifying and analog filtering of sensor output

Issues:

• S ignal conditioning

• S ignal transmission

• Data display

• O perating life

• C alibration

• Impedance of sensor and system

• S upply voltage

• Frequency response

• F iltering

• Amplifier provides signal strength and sensor impedance

• F iltering needed to suppress noise

• If needed, quite complex functions can be done with analog electronics, but many functions are better done in digital electronics

• easier

• cheaper

• need less room


Analog-digital conversion (ADC)

• The measurement must usually be changed to digital form for

• further processing and calculations

• storing to memory

• sending the data

• or just an economical reason

• ADC often included in MC U:s, e.g. MS P430F1xx

• Is the resolution (8 or 12-bit) enough?

Issues:

• S ample rate

• R esolution (8, 12, 16-bit)

• Accuracy

• Power consumption

• Price


Digital signal processing

• More complex signal processing

• summing many sensors (e.g. 3-axis accelerometers)

• pattern recognition, e.g. step counters, speech recognition

• C an be done in

• AS IC , for cheap mass-production

• DS P, for high-speed number crunching

• MC U (microcontroller), medium level calculations, control software

Issues:

• F ixed-point vs. floating-point DS P

• Data precision

• S peed

• Power usage

• Price

• Internal ADC

• Need for flexible programming: MC U vs. DS P

• Programming languages: Assembly vs. C /C ++ or J ava


Microcontroller

• S oftware controlling a smart sensor system, e.g.

• measurements• communications• data memory• real time clock

• Usually includes • ADC (DAC )• timers• serial ports (S PI, I2C , UAR T)• flash memory

• Power-efficient, cheap, flexible• Also called MC U or µC

MS P430F169 by Texas Instruments

• Low supply-voltage 1.8 - 3.6 V • Ultra-low power consumption:

• Active: 330 µA at 1 MHz, 2.2 V• S tandby: 1.1 µA• Off (R AM retention): 0.2 µA

• Wake-up from standby in less than 6 µs • 16-Bit R IS C , 125-ns instruction cycle• Program memory 60 kB (flash), R AM 2048 B• 8-channel 12-Bit ADC with internal reference,

sample-and-hold and autoscan• Dual channel 12-Bit DAC with synchronization • 16-Bit Timer_ A & Timer_ B with 3/7 C C R• On-chip comparator • 2 serial interfaces: UAR T or S PI or I2C ™• S upply voltage supervisor/monitor• Brownout detector • Bootstrap loader • S erial onboard programming


Networking sensors over radio

GPRS/3Gnetwork

Internet

C ellular

GPRS/3GnetworkGPRS/3Gnetwork

InternetInternet

C ellular

RFIDRFID

UWB

Bluetooth

Low E ndWLAN


BluLite (or Bluetooth Low End Extension)

• Low E nd E xtension for Bluetooth is designed• to complement Bluetooth by creating a wireless solution that• allows small devices that are limited in battery power, size, weight and cost to have a wireless

connection with mobile terminals• without adding yet another radio to mobile terminals (as Z igBee)

• Optimized for irregular data exchange between Bluetooth enabled mobile terminals and button cell batter powered small devices

• C oncept assumes two device classes• Dual-mode (Bluetooth 1.2 with Low E nd mode) for terminals• S tand-alone (Low E nd mode alone) for sensors and enhancements

CommonHost

IF

Dual-mode device (i.e. terminal) Stand-alone device(e.g. 3D accelometer node)

BluetoothBB/MAC

LEE MAC/(BB)Common

RFSensorASIC

LEEASIC

Stand-alone device(e.g. fitness gadget)

SensorASIC

LEEASIC


BluLite radio

2400 2401 2402 2403 2481 2482 24832480

Bluetooth channelsChannels of theproposed system

IEEE 802.11b channelin North America and Europe

2403 2406 2433 2436 248124782463 2466

One default initialization channel, non-overlapping with Bluetooth

Two secondary initialization channels, for jamming resistance

24 Unicast channels for user data

MHz

MHz

Low End Extension channels


BluLite radio parameters with 1 Mbps

•Physical bit rate 1 Mbps

•Frequency band 2.4 G Hz (IS M band)

•Duplex TDD

•C o-existence of multiple devices• C onnection setup channel C S MA

• Data delivery F DMA

•J amming avoidance FDMA

•PDU payload• Byte aligned, variable length, max 255 bytes

•Bit rate excluding PHY and MAC overheads

• Uni-directional with AR Q , max 890 kbps

• Bi-directional with AR Q , max 2 x 471 kbps


Basic functions of BluLite radio

1. ADVE RTIS E : Makes the local device visible and connectable to all remote devices within reach. Low-power protocols optimized for this state. A possibility for an application dependent trade-off between connection set-up delay and the power consumption.

2. S C AN: R eturns the addresses and short description of the advertising remote devises within reach.

3. C ONNE C T: E stablishes a point-to-point connection with an advertising remote device. 4. C ONNE C TE D: Provides point-to-point bi-directional data delivery with error detection,

AR Q, segmentation, role switch and a low-activity mode. An evolution path to point-to-multipoint, requiring additions only in master capable devices.

OFF IDLE

CONNECT

SCAN

ADVERTISE

CONNECTED


Symbian

POP

1. Host (N6630)

M-API

Applicationspace

SSI (Client)

SSI (virtualServer)

CommunicationLayer (U-ULIF)

RFID (front end)

Sensors

Digital sensormanagement

(memory map)

RFID Sensor

2. SEMBO

CART

SPI

SSI server

UART SPI/IIC DA

3. Sensor-HW

MSP430

FPGA

5. RF-module

Radio BBs

Device drivers

MCU

ADC DAC

SPI

4. LOCOS

1.

SSI server

UART SPI/IIC DA

2. Sensor-HW

MSP430

M-SPI

FPGA

BT LEE

4. LEE ASIC

Radio sensor node

1.3.

ULIFDevice drivers

M-SPI

nanoIP

Symbian

POP

1. Host (N6630)

M-API

Applicationspace

SSI (Client)SSI (Client)

SSI (virtualServer)

SSI (virtualServer)

CommunicationLayer (U-ULIF)

RFID (front end)

Sensors

Digital sensormanagement

(memory map)

RFID Sensor

2. SEMBO

CART

SPI

SSI server

UART SPI/IIC DA

3. Sensor-HW

MSP430

FPGA

5. RF-module

Radio BBs

Device drivers

MCU

ADC DAC

SPI

4. LOCOS

1.

SSI server

UART SPI/IIC DA

2. Sensor-HW

MSP430

M-SPI

FPGA

BT LEE

4. LEE ASIC

Radio sensor node

1.3.

ULIFDevice drivers

M-SPI

nanoIP

SSI server

UART SPI/IIC DA

2. Sensor-HW

MSP430

M-SPI

FPGA

BT LEE

4. LEE ASIC4. LEE ASIC

Radio sensor node

1.3.

ULIFDevice drivers

M-SPI

nanoIP

Mimosa Architecture

Internet

Back-end server

UMTSG PR S


Simple Sensor Interface (SSI) protocol

• A simple protocol for reading smart sensors over, e.g., BT LE E

• Also provided for R FID sensor tags • Memory map of sensor data on

• C ompatible with IS O 18000-4

• S upport for multiple sensors on multiple devices

• S upport for data polling or streaming

• Developed in co-operation withS uunto, Vaisala, Mermit, C E A-LE TI, O ulu University and Ionific

• Development of the specification keeps backward compatibility (v0.4-)

• For specifications, source code and discussion forum, visit http://ssi-protocol.net

• C lient-server architecture

• Terminal has client software

• S ensor unit has server software

• C lient can

• poll sensors

• ask the server (Observer) to stream data to client (Listener)

• read and modify the configuration of the server

• C ommands have two forms

• C apital letter (“N”), no checksum

• Low case (“n”), the payload has a C R C checksum


SSI v1.0 command base

Free data

E rror

S treaming data

Read data

C onfiguration

S ensor discovery

F ree data for custom purposes⇮0x46 / 0x66F / f

E rror messages⇮0x45 / 0x65E / e

S ensor listener created→0x4A / 0x6AJ / j

R equest sensor listener←0x4C / 0x6CL / l

Delete sensor observer→0x4B / 0x6BK / k

S ensor observer created←0x59 / 0x79Y / y

C reate sensor observer→0x4F / 0x6FO / o

S ensor data response with one byte status field←0x44 / 0x64D / d

S ensor data response←0x56 / 0x76V / v

R equest sensor data→0x52 / 0x72R / r

S et configuration data for a sensor→0x53 / 0x73S / s

C onfiguration data response←0x58 / 0x78X / x

G et configuration data for a sensor→0x47 / 0x67G / g

R eset S S I device→0x5A / 0x7AZ / z

Discovery reply←0x4E / 0x6EN / n

Discover sensors→0x43 / 0x63C / c

Query reply←0x41 / 0x61A / a

Query→0x51 / 0x71Q / q

DescriptionDir.C ommand


Example SSI command: Discovery reply

• S ensor device answers to Discovery command sent by a mobile terminal

• Discovery R eply message contains information about one or more sensors.

• The device answers with its address, command name (N or n) and sensor data

• E ach sensor is identified with• S ensor Id – 2bytes

• Description – 16 byte AS C II

• Unit – 8 byte AS C II

• Type – 1 byte

• S caler - signed 1 byte

• Min – minimum sensor reading value

• Max – maximum sensor reading value

• The reply can carry either one sensor per N command or many depending on buffer size

• UAR T or nanoIP frame provides the information about the length of a single message

Client Server

C

. . .

Terminal Sensor unit

N (sensor info )

N (sensor info )

Addr N/n

1 1

Sensor Id 1

2

Sensor desc.

16

Unit

8

Type Scaler

1 1

. . .MIn Max

44


nanoIP networking

• An open-source networking architecture

• Minimal overheads

• Wireless networking

• Local addressing

• NanoIP makes use of the MAC address of underlying network technology rather than IP addresses

• Used with nanoUDP (User Datagram Protocol) or nanoTC P (Transmission C ontrol Protocol)

• nanoUDP does not provide reliability or ordering

• nanoTC P provides retransmissions and flow control

• Mimosa uses nanoUDP

• http://www.cwc.oulu.fi/nanoip/

ULIF (BluLiteMAC )

nanoIP

nanoUDP

S S I


Open source SSI/nanoIP implementation

• S S I v0.4 over nanoUDP/nanoIPprovided by O ulu University

• S S I v1.0 (nanoUDP/nanoIP) being finalized by Nokia R esearch C enter, will be open source

• Works over BluLite (Bluetooth LE E )

• 1 byte protocol type (nanoIP)

• 4 bytes nanoUDP header

• 2 byte payload + C R C length

• 1 byte S ource port (40 for S S I)

• 1 byte Destination port (40 for S S I)

• n bytes

• S S I payload

• 2 bytes

• optional C R C checksum

Prtcol PayloadLenH LenL CRC

1 11 n 2

Source

1

Dest.

1


Mimosa API’s for 3 rd parties

MIMO S A Local C onnectivity Layer

MIMO S A S ensor Layer

MIMO S A C ontext Awareness Layer

MIMO S A Ambient User Interface Layer

LC _ API

S ensor_ API

C ontext_ API

UI_ API

Back-end server

Local MIMO S A S W ApplicationsIP

J ava & C ++ implementation


Sensor Management Board

• C ontrols the sensors (host)

• C ontrols the sensors and BTLE E (S ensor R adio Node)

• R eal time clock (with its own battery)

• C onnectors for• LOC OS and/or C AR T

• S ensor board (UAR T, S PI/I2C , general digital I/O , 8-channel analog)

• J TAG programming interface

• Debugging ports (UAR T)

• IR Q ports

• MC U runs S S I/nanoIP and device drivers for sensors


Sensor Management Board

• C ontrols the sensors (host)

• C ontrols the sensors and BTLE E (S ensor R adio Node)

• R eal time clock (with its own battery)

• C onnectors for• LOC OS and/or C AR T

• S ensor board (UAR T, S PI/I2C , general digital I/O , 8-channel analog)

• J TAG programming interface

• Debugging ports (UAR T)

• IR Q ports

• MC U runs S S I/nanoIP and device drivers for sensors

text

32.7

68 k

Hz

crys

tal

8 M

Hz

crys

tal

SEMBO

MCUMSP430F169

US

AR

T0

US

AR

T1

Deb

uggi

ng:

SP

I0 +

U

AR

T1

IRQ

sJT

AG

CA

RT

Real time clock

DS1305E

32.768 kHz crystal

3V BAT

SEPPO / SENSOR BOARD

LOCOS and / or CART

I2C

M-SPI

3.3 V POWER

UART

I2C

UART

3.3 V POWER

Ext

erna

lpo

wer

AD

C

DA

C

SPI

ANALOG

32.768 kHz clock

UART


Mimosa terminal

• Nokia 6630 phone as terminal

• Attached electronics (C AR T, LO C O S , S E MBO , R F) provide the Mimosa hardware functionality

• J ava software on N6630 will provide the user interface, context awareness, sensor management etc.

• LO C O S board as motherboard of attached electronics

• S E MBO provides local sensor control

• S E PPO (or other) sensor board connected to S E MBO with a standard interface

• R F part controlled with F PG A on LO C O S on baseband-module

• S eparate R F module

SEMBO

CART

SPI

SSI server

UART SPI/IIC DA

Sensor-HW

MSP430

FPGA

RF-module

Radio BBs

Device drivers

MCU

ADC DAC

SPI

LOCOSSEMBO

CART

SPI

SSI server

UART SPI/IIC DA

Sensor-HW

MSP430

FPGA

RF-module

Radio BBs

Device drivers

MCU

ADC DAC

SPI

SEMBO

CART

SPI

SSI server

UART SPI/IIC DA

Sensor-HW

MSP430

FPGA

RF-module

Radio BBs

Device drivers

MCU

ADC DAC

SPI

LOCOS


Mimosa terminal - 2

SEPPO

SEMBO

LOCOS

CART

Connection to RF board

Connection to phone


Sensor Radio Node

• S mart sensor which can be read over BT LE E connection

• E MMI board provides Bluetooth LE E for communications with mobile terminals

• S E MBO for controlling BT LE E , running the S S I server and sensor drivers

• LO C O S acts as motherboard

• S E PPO (or other) as sensor hardware board via standard connector

• UAR T

• S PI / I2C

• 8 analog channels

• 15 unspecified digital I/O pins

M-SPI

SSI server

UART SPID

A

Sensor-HW

MSP430

M-SPI

FPGA

BT LEE

LEE ASIC

Device drivers

LOCOS

SEMBO

EMMI

M-SPI

SSI server

UART SPID

A

Sensor-HW

MSP430

M-SPI

FPGA

BT LEE

LEE ASICLEE ASIC

Device drivers

LOCOS

SEMBO

EMMI


Sensor Radio Node - 2

LOCOS SEMBOEMMI

SEPPO


Sensors demonstrated on Mimosa platform

I2C

Amplified analog

Amplified analog

Amplified analog

Digital

Interface

Fraunhofer-IS IT, C E A-LE TI, S TMicroelectronics

G yroscope

F itness & healthFraunhofer-IS IT, C ardiplus, Åmic

Lactate, glucose

F itness & health, streaming data over S S I/nanoIP/BluLite

C ardiplusE C G

F itness & healthNokiaFat %

Weather station, S S I demonstration

Nokia, (S ensirion, Intersema)

Humidity, temperature, pressure

NotesProviderS ensor


Weather station

• Demonstration of S S I use

• Weather information: Temperature, Humidity / dew point, and Pressure

• Intersema MS 5534A pressure sensor

• Pressure range 300-1100 mbar

• Internal 15 Bit ADC

• 6 coeff. software compensation on-chip

• 3-wire serial interface

• 1 system clock line (32.768 kHz)

• 35 ms measurement time

• S ensirion S HT11 humidity sensor


Weather station

• Demonstration of S S I use

• Weather information: Temperature, Humidity / dew point, and Pressure

• Intersema MS 5534A pressure sensor

• S ensirion S HT11 humidity sensor

• Internal 14-bit ADC

• Fully calibrated

• Internal power regulation

• R ange

• Humidity 0 – 100 %

• Temperature -40 – 128°C

• 2-wire serial interface (not I2C )

• 11/55/210 ms for a 8/12/14bit measurement.


Fat percentage

• Actually measures body water content (TBW)

• From TBW, fat-% and dehydration (∆TBW) calculated

• 4-point measurement of impedance with 50 kHz signal

• Amplified analog output

• Low-noise OPA2350 two-channel

• Also used for 2-point measurement of surface impedance, G alvanic S kin R esponse (G S R )

• S kin stratum corneum humidity

• S tress measurement

AN

ALO

G IN

TE

RF

AC

E E

LEC

TR

ON

ICS E1

SIGNAL IN

E2M1

E3M2

E4SIGNAL OUT

C50KHZ

GND

+3.3V

FAT_CS

V_FAT

I_FAT

REF_FAT

AD

C

SE

MB

O

INT

ER

FA

CE


Lactate & glucose sensors

• Fraunhofer-Institut fürS iziliziumtechnologie (Itzehoe, G ermany) makes the sensor

• Åmic (Uppsala, S weden) makes a needle array to penetrate outer layer of skin

• Measures the lactate or glucose content of interstitial fluid

• Lactate and glucose sensors differ only on the enzyme used

• Amplified analog connection to S E MBO


RFID sensor tag

•Virtual server on the terminal device answers to the S ensor API when connecting to R FID sensors

•Virtual server translates the commands to the R FID reader to read a specified memory area of the tag

•0x53 (for AS C II “S ”) in address 0x0C (Tag memory layout) defines the memory layout to be S S I compliant

•Memory mapping designed for one or more sensors per tag

•Memory layout designed to be convenient for S S I use

User data (layout defined by S S I).0x12 –

Tag memory layout. This defines tag to be S S I compliant sensor.0x0C – 0x116

Tag hardware type0x0A – 0x0B

Tag manufacturer0x08 – 0x094

Tag ID0x00 – 0x078

FieldBytes


RFID memory mapping: Sensor data space

Optional configuration data or 2nd sensorn bytes0x3E –n

Not defined yet. Could be, e.g., time needed before sensor value is valid.

3 bSensor control0x3B – 0x3D

0x01Bits 0 – 7 will be written by the reader to request the tag to write the sensor data

1 bActivate sensor0x3A

4

0x00000064Maximum value the sensor can provide.4 b HEXMaximum value0x36 – 0x39

0x00000000Minimum value the sensor can provide.4 b HEXMinimum value0x32 – 0x358

“C”Constant unit description. 8 b ASCIIUnit0x2A – 0x318

“Temperature”Constant sensor description16 b ASCIISensor description0x1A – 0x2916

For future use. Could be, e.g., number of sensors.

1 bEmpty0x19

0x01Sensor status. Bits 0 – 7 indicate if the sensor values are valid data (bit = 1) or not yet valid (bit = 0).

1 b HEXStatus0x18

0x001 b HEXMultiplier0x17

0x01Describes the type of the Sensor value (0x00 = float, 0x01 = signed integer…)

1 b HEXType 0x16

0x00000014Variable sensor value4 byte HEXSensor value0x12 – 0x15

8

ExampleDescriptionTypeField nameByte address


Questions & Answers

Date post:	19-May-2015
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Smart sensor architecture 2006

Technology