More Related Content Similar to Smart sensor architecture 2006 (20) Smart sensor architecture 20061. Smart Sensor Architecture
Smart Sensor System Architecture in Mimosa
project
Iiro Jantunen / Nokia Research Center
Tutorial Ambient Intelligence,
Toulouse, March 10, 2006
1
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
2. Contents
•What is a smart sensor system?
• Transducer, analog electronics, ADC , digital electronics
•O pen 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 F ID connection
• Many sensors in many devices over many radio technologies
2
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
3. From sensors to smart sensors
Passive sensor (photodiode)
S ensor
Active sensor (S T 3-axis accelerometer)
Wireless smart sensor
3
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
4. 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
4
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
• 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)
5. Transducer
• C onverts between physical
properties
Measurement
Typical/common
techniques
• The resulting property can be
Acceleration
Piezoelectric, capacitive
Displacement, position,
proximity
R eluctance,
optoelectronic, ultrasonic,
radar
• Voltage
F low
Pressure difference
• O ptical power
F orce
Piezoresistive
• E lectrical measurand needs an
amplifier/filtering circuit to provide
electrical power, impedance etc.
Humidity
R esistive, capacitive
Location
G PS
Time
C lock signal
• O ptical measurand needs a
optoelectrical transducer with the
same properties
S ound, pressure
C apacitive
R adiation
O ptoelectronic
G as concentration
Tuned laser &
optoelectronic
• E lectrical capacitance
• C urrent
5
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
6. Non-ideal behavior of sensors
C haracteristic
S ensor Design
Nonlinearity
C onsistent
R educe
Drift
Minimize
C ompensate
O ffset
S ensor Interface
C alibrate
Time dependence of offset
Minimize
C alibrate/reduce
Auto-zero
Time dependence of sensitivity
Nonrepeatability
MC U/DS P
Auto-range
R educe
C ross-sensitivity to temp and strain
C alibrate
Hysteresis
Predictable
Low resolution
Increase
Amplify
Low sensibility
Increase
S tore value and correct
Amplify
Unsuitable output impedance
Buffer
S elf-heating
Increase cooling
Unsuitable frequency response
Modify
R educe power use
F ilter
Temperature dependence of offset
S tore value and correct
Temp. dependence of sensitivity
S tore value and correct
F rom R . F rank: Understanding S mart S ensors, 2n ed.,
6
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
7. Amplifying and analog filtering of sensor output
• Amplifier provides signal strength and
sensor impedance
Issues:
• F iltering needed to suppress noise
• S ignal transmission
• If needed, quite complex functions
can be done with analog electronics,
but many functions are better done in
digital electronics
• Data display
• S ignal conditioning
• O perating life
• C alibration
• easier
• Impedance of sensor and system
• cheaper
• S upply voltage
• need less room
• F requency response
• F iltering
7
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
8. 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 P430F 1xx
• Is the resolution (8 or 12-bit) enough?
8
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
Issues:
• S ample rate
• R esolution (8, 12, 16-bit)
• Accuracy
• Power consumption
• Price
9. 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
Issues:
• F ixed-point vs. floating-point DS P
• Data precision
• S peed
• Power usage
• AS IC , for cheap mass-production
• Price
• DS P, for high-speed number
crunching
• Internal ADC
• MC U (microcontroller), medium level
calculations, control software
9
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
• Need for flexible programming: MC U
vs. DS P
• Programming languages: Assembly
vs. C /C ++ or J ava
10. 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
10
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
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
• O ff (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
• O n-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
11. Networking sensors over radio
RF ID
Internet
WL AN
L ow E nd
Bluetooth
UWB
11
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
C ellular
GPRS/3G
network
12. 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)
• O ptimized 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
Dual-mode device (i.e. terminal)
E
/(BB)
C
ommon LE MAC
C
ommon
Host
Bluetooth
RF
IF
BB/MAC
12
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
Stand-alone device
(e.g. 3D accelometer node)
S
ensor
AS
IC
LE
E
AS
IC
Stand-alone device
(e.g. fitness gadget)
S
ensor
AS
IC
LE
E
AS
IC
13. BluLite radio
Channels of the
proposed system
2401
2400
IEEE 802.11b channel
in North America and Europe
2402
2403
Bluetooth channels
2480
2481
2482
2483
MHz
Low End Extension channels
2403
2406
2433
2436
2463
2466
2478
2481 MHz
One default initialization channel, non-overlapping with Bluetooth
T secondary initialization channels, for jamming resistance
wo
24 Unicast channels for user data
13
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
14. BluLite radio parameters with 1 Mbps
•Physical bit rate 1 Mbps
•F requency 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 F DMA
•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
14
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
15. Basic functions of BluLite radio
ADVERTISE
OFF
IDLE
SCAN
CONNECTED
CONNECT
1.
2.
3.
4.
15
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.
S C AN: R eturns the addresses and short description of the advertising remote devises
within reach.
C ONNE C T: E stablishes a point-to-point connection with an advertising remote device.
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-tomultipoint, requiring additions only in master capable devices.
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
16. Mimosa Architecture
Radio sensor node
Back-end server
RFID Sensor
MSP430
4. LEE ASIC
SSI server
Sensors
nanoIP
Internet
FPGA
Digital sensor
management
(memory map)
D
M-SPI UART SPI/IIC
A
BT LEE
RFID (front end)
UMTS
G PR S
M-SPI
1.
3.
1. Host (N6630)
Application
space
M-API
SSI
SSI
(Client)
5. RF-module
1.
(virtual
Server)
4. LOCOS
2. SEMBO
MSP430
Communication
Layer (U-ULIF)
SSI server
Symbian
MCU
SPI
ADC
Device drivers
CART
FPGA
UART SPI/IIC D
A
DAC
Radio BBs
POP
SPI
3. Sensor-HW
16
© 2006 Nokia
Device drivers
ULIF
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
2. Sensor-HW
17. Simple Sensor Interface (SSI) protocol
• A simple protocol for reading smart
sensors over, e.g., BT LE E
• Also provided for R F ID 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 with
S uunto, Vaisala, Mermit, C E A-LE TI,
O ulu University and Ionific
• Development of the specification
keeps backward compatibility (v0.4-)
• F or specifications, source code and
discussion forum, visit
http://ssi-protocol.net
17
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
• C lient-server architecture
• Terminal has client software
• S ensor unit has server software
• C lient can
• poll sensors
• ask the server (O bserver) 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
18. SSI v1.0 command base
C ommand
Dir.
Description
Q /q
0x51 / 0x71
→
Q uery
A /a
0x41 / 0x61
←
Q uery reply
C /c
0x43 / 0x63
→
Discover sensors
N /n
0x4E / 0x6E
←
Discovery reply
Z /z
0x5A / 0x7A
→
R eset S S I device
G /g
0x47 / 0x67
→
G et configuration data for a sensor
X /x
0x58 / 0x78
←
C onfiguration data response
S /s
0x53 / 0x73
→
S et configuration data for a sensor
R /r
0x52 / 0x72
→
R equest sensor data
V /v
0x56 / 0x76
←
S ensor data response
D /d
0x44 / 0x64
←
S ensor data response with one byte status field
O /o
0x4F / 0x6F
→
C reate sensor observer
Y /y
0x59 / 0x79
←
S ensor observer created
K /k
0x4B / 0x6B
→
Delete sensor observer
L /l
0x4C / 0x6C
←
R equest sensor listener
J /j
0x4A / 0x6A
→
S ensor listener created
E rror
E /e
0x45 / 0x65
⇮
E rror messages
F ree data
F /f
0x46 / 0x66
⇮
F ree data for custom purposes
S ensor discovery
C onfiguration
Read data
S treaming data
18
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
19. Example SSI command: Discovery reply
• S ensor device answers to Discovery
command sent by a mobile terminal
C
• Discovery R eply message contains
information about one or more sensors.
N (sensor info )
Client
Server
N (sensor info )
Terminal
• The device answers with its address,
command name (N or n) and sensor data
Sensor unit
. . .
• E ach sensor is identified with
• The reply can carry either one sensor per
N command or many depending on buffer
size
• S ensor Id – 2bytes
• Description – 16 byte AS C II
• Unit – 8 byte AS C II
• UAR T or nanoIP frame provides the
information about the length of a single
message
• Type – 1 byte
• S caler - signed 1 byte
• Min – minimum sensor reading value
• Max – maximum sensor reading value
1
Addr
19
1
N/n
© 2006 Nokia
2
Sensor Id 1
16
Sensor desc.
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
8
Unit
1
1
Type
Scaler
4
4
MIn
Max
. . .
20. nanoIP networking
• An open-source networking architecture
• Minimal overheads
• Wireless networking
SSI
• 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/
20
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
nanoUDP
nanoIP
ULIF (BluLite
MAC )
21. Open source SSI/nanoIP implementation
• S S I v0.4 over nanoUDP/nanoIP
provided by O ulu University
• 1 byte protocol type (nanoIP)
• 4 bytes nanoUDP header
• 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 )
• 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
1
1
1
1
Prtcol
21
1
LenH
LenL
Source
Dest.
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
n
Payload
2
CRC
22. Mimosa API’s for 3rd parties
Back-end server
IP
Local MIMO S A
S W Applications
UI_ API
C ontext_ API
J ava & C ++
implementation
MIMO S A Ambient
User Interface Layer
MIMO S A C ontext
Awareness Layer
S ensor_ API
MIMO S A
S ensor Layer
LC _ API
MIMO S A
Local C onnectivity Layer
22
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
23. 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
• LO C O S 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
23
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
24. Sensor Management Board
24
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
3.3 V POWER
UART
32.768 kHz clock
UART
I2C
SPI
ADC
DAC
32.768 kHz
crystal
IRQs
USART0
I2C
MCU
text
MSP430F169
JTAG
M-SPI
LOCOS
and / or
CART
UART
8 MHz
crystal
CART
USART1
External
power
• LO C O S 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
SEMBO
Debugging:
SPI0 +
UART1
• 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
32.768 kHz
crystal
3.3 V POWER
3V
BAT
ANALOG
Real time
clock
DS1305E
SEPPO /
SENSOR
BOARD
25. 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
25
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
RF-module
LOCOS
SEMBO
MSP430
ADC
SSI server
DAC
CART
Device drivers
MCU
SPI
UART
SPI/IIC
FPGA
D
A
Radio BBs
SPI
Sensor-HW
26. Mimosa terminal - 2
SEPPO
Connection
to RF board
SEMBO
LOCOS
CART
Connection
to phone
26
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
27. 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
LEE ASIC
SEMBO
MSP430
EMMI
SSI server
Device drivers
FPGA
M-SPI
UART
SPI
BT LEE
• 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
27
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
M-SPI
Sensor-HW
LOCOS
D
A
28. Sensor Radio Node - 2
SEPPO
EMMI
28
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
LOCOS
SEMBO
29. Sensors demonstrated on Mimosa platform
S ensor
Provider
Notes
Humidity,
temperature,
pressure
Digital
Nokia, (S ensirion,
Intersema)
Weather station,
S S I demonstration
F at %
Amplified
analog
Nokia
F itness & health
EC G
Amplified
analog
C ardiplus
F itness & health,
streaming data over
S S I/nanoIP/BluLite
Lactate,
glucose
Amplified
analog
F raunhofer-IS IT,
C ardiplus, Åmic
F itness & health
G yroscope
29
Interface
I2C
F raunhofer-IS IT, C E ALE TI, S TMicroelectronics
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
30. 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
30
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
31. 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
• F ully 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.
31
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
32. Fat percentage
• Actually measures body water content
(TBW)
• Amplified analog output
• Low-noise O PA2350 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
32
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
C50KHZ
V_FAT
ADC
• 4-point measurement of impedance
with 50 kHz signal
+3.3V
SEMBO
INTERFACE
• F rom TBW, fat-% and dehydration
(∆TBW) calculated
FAT_CS
I_FAT
REF_FAT
GND
ANALOG INTERFACE ELECTRONICS
SIGNAL IN
M1
M2
SIGNAL OUT
E1
E2
E3
E4
33. Lactate & glucose sensors
• F raunhofer-Institut für
S 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
33
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
34. RFID sensor tag
•V irtual server on the terminal device answers to the S ensor
API when connecting to R F ID sensors
•V irtual server translates the commands to the R F ID 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
Bytes
Field
8
0x00 – 0x07
Tag ID
4
0x08 – 0x09
Tag manufacturer
0x0A – 0x0B
Tag hardware type
0x0C – 0x11
Tag memory layout. This defines tag to be S S I compliant sensor.
0x12 –
User data (layout defined by S S I).
6
34
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
35. RFID memory mapping: Sensor data space
Byte address
Field name
Type
Description
Example
0x12 – 0x15
Sensor value
4 byte HEX
Variable sensor value
0x00000014
0x16
Type
1 b HEX
Describes the type of the Sensor value
(0x00 = float, 0x01 = signed integer…)
0x01
0x17
Multiplier
1 b HEX
0x18
Status
1 b HEX
Sensor status. Bits 0 – 7 indicate if the
sensor values are valid data (bit = 1) or
not yet valid (bit = 0).
0x19
Empty
1b
For future use. Could be, e.g., number of
sensors.
16
0x1A – 0x29
Sensor description
16 b ASCII
Constant sensor description
“Temperature”
8
0x2A – 0x31
Unit
8 b ASCII
Constant unit description.
“C”
0x32 – 0x35
Minimum value
4 b HEX
Minimum value the sensor can provide.
0x00000000
0x36 – 0x39
Maximum value
4 b HEX
Maximum value the sensor can provide.
0x00000064
0x3A
Activate sensor
1b
Bits 0 – 7 will be written by the reader to
request the tag to write the sensor data
0x01
0x3B – 0x3D
Sensor control
3b
Not defined yet. Could be, e.g., time
needed before sensor value is valid.
n bytes
Optional configuration data or 2nd sensor
8
8
4
n
0x3E –
35
© 2006 Nokia
S mart S ens or Architecture.ppt / 2006-03-10 / IJ
0x00
0x01
Editor's Notes Issues:
Cost
Size, weight
Power use
Self-testing, self-calibration
Wired/wireless communication
Stand-alone components are far away from ideal characteristics desired for measurements.
Cost: Only a few cents extra for a BT chip
Power usage: 10% of a BT chip
Low End Extension (LEE) of Bluetooth is the technology to solve a simple mismatch. There are several small devices that could add value by having wireless radio connection to mobile terminal but cannot bear the power consumption and cost associated to Bluetooth. However, the mobile terminals will have Bluetooth as the short-range wireless solution. Bluetooth LEE tackles the mismatch by introducing minor additions to the Bluetooth chip in the mobile terminals that allows designs that will produce major saving in power consumption and cost in the chips embedded into small devices. Examples of the small devices include wireless sensors, toys, wireless pens etc
Instead of replacing the existing wired connections with the wireless as targeted by Bluetooth, the BluLite targets to provide new connections between the Bluetooth enabled mobile phones and the devices that cannot bare the additional price and/or power consumption of the Bluetooth radio but could benefit from the connectivity. Further, the target use scenarios require some processing in the device connected to the mobile phone and there is not necessary line-of-sight connection. Thus, IRDA and RFID solutions do not meet the requirements. The following categorization highlights the BluLite use cases.
IrDa fails to meet the link distance, the power consumption and the pointing criteria. Furthermore, the current co-existence of IrDa and Bluetooth is not a cost- and size-efficient solution for mobile terminals.
ZigBee would result in a considerable cost and size penalty to the mobile terminals since it results in yet another radio alongside Bluetooth. It’s as complex as Bluetooth and the power-efficient protocols are limited to home and industrial automation use.
RFID is difficult to benchmark due to the plurality of RFID technologies. The RFID technologies that feature the essence of the technology, passive tag, would either fail in link distance, voice support and in cost increase in mobile terminal.
Bluetooth technology is limited by its peak and average power consumption, cost, piconet topology, and connection set-up times. The consensus is that Bluetooth technology cannot be scaled down to the appropriate power and cost levels for small peripherals just by applying advanced implementation techniques. Rather, the specification needs to be changed in some areas to account for the mismatch in design requirements of small peripherals and mobile terminals.
The MIMOSA sensor architecture is defined to be modular, freely scalable and has open interfaces for third parties through open Simple Sensor Interface (SSI) protocol. Plug-in type implementation of sensors using SSI is the key to modularity. Using SSI system will detect what sensors are available regardless their location in terminal, in RFID tag, or in sensor radio node. This modular architecture is shown here. The Sensor API on the host device will keep a list of available sensors and provide functions for accessing the sensors, be they local (connected directly to the host device) or remote (RFID or BT LEE connected).
NanoIP, which stands for the nano Internet Protocol, is a concept that was created to bring Internet-like networking services to embedded and sensor devices, without the overhead of TCP/IP. NanoIP was designed with minimal overheads, wireless networking, and local addressing in mind.
The protocol actually consists of two transport techniques, nanoUDP, which is an unreliable simple transport, and nanoTCP, which provides retransmissions and flow control. A socket-compatible API is provided which makes the use of the protocols very similar to that of IP protocols. The only difference is in addressing and the port range. NanoIP makes use of the MAC address of underlying network technology rather than IP addresses, which are not needed for local networks. The port range is 8-bits, 256 ports each for source and destination. In addition to nanoIP itself, a range of compact application protocols have been developed, such as nHTTP and nPing.