Transcript Sensor specification

Sensor specification
Sensor Network Group
Sensor Specification
• Constraints of tiny sensors
– Power: For survival and sensing.
– Computation: Application and data
aggregation strategies drive the
computational requirements
– Sensor: Different types of sensors like
temperature, pressure, humidity, light, sound,
acceleration, magnetic field etc.
– Communication: Range and noise in media
are the major factor.
Sensor Specification
• Our choice of sensor is SMART Dust. But,
SMART Dust is not yet available in the market
and not yet in a position to use for our research
about Sensor Network.
• In this presentation, we will discuss about the
alternatives available with the requirements
mentioned in the last slide. Mostly it is the
research done for developing Commercial ofthe-shelf (COTS) Dust, which can be described
as a test bed for SMART Dust for immediate
unavailability of SMART Dust in market.
Sensor Specification
• Power:
– Lithium Battery:
• Conforms to RF chip requirement of 3 v of portable
power source (i.e., high energy density)
• Doesn’t have high current capacity.
– Nickel-metal hybrid batteries:
• Output 260 times more than lithium.
• Voltage regulator require additional power to run,
added noise to the system & add extra component
Sensor Specification
• Computation:
– Important features of microprocessor to be
choosen
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Power
Memory size
Fast re-programmability
A/D channel
A 3 v operating supply
Sensor Specification
Atmel AVR
Microchip
AT90LS8535
PIC16F877
MC68H(R)C Strong
Thumb
908JL3
AT91M404
Flash
memory (k)
4
8 x 14
4
External
memory
Endurance
1k
1k
10 k
N/A
MIPS/mA
1.25 (min)
1.66 (prelim)
0.1(typical)
0.6
A/D channel
8 (10 bit)
no
2.7-5.5v
35
8 (10 bit)
yes
2.0-5.5v
40
12 (8 bit)
yes
2.7-3.3v
23
0
Yes
2.7-3.6v
100
IAP
Operating v
I/O pins
Sensor Specification
• Strong thumb is the processor of choice.
• Strong Arm is a little variation to Strong
Thumb, but with all the properties
compared, Strong Thumb is considered as
a better fit as a processor for our Sensor
Network application.
Sensor Specification
• Sensors
– Two major groups:
• Weather monitor
• Motion detector
– Most of them have voltage range of 2.7v-5.5v
– Current consumption 600 micro-Amp other
than light sensor & humidity sensors (200)
– Temperature dependence is negligible for
most of them.
Sensor Specification
• Communication:
– Types are
• Acoustic
• RF
• Optical
– Our choice of communication is RF. Reasons
are well described in earlier presentations.
Sensor Specification
– Available RF communications:
• Bluetooth
• RF monolithics
Sensor Specification
Thank You