11 wireless sensor networks (wsn) cpu group progress presentation almir davis yong zhang halligan...
TRANSCRIPT
11
Wireless Sensor Networks (WSN)
CPU GroupProgress Presentation Almir DavisYong Zhang
Halligan Hall 03/17/2005
22
Agenda
Sensor Card Diagram
Choosing Power Supply
CPU Design Progress
CPU New Features
Questions from the Proposal Presentation
Current Questions
33
WSN Block Diagram
TRANCEIVERCPU
BASE STATIONFIXED LINE NETWORK
WIRELESS SENSOR
NETWORK
SENSOR CARD
TRANCEIVERCPU
SENSOR CARD
TR
AN
CE
IVE
RC
PUS
EN
SO
R C
AR
D
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Sensor Card
CPU
TIO SIO
I/O to WSN
A/D
Display and debug
interfaceTranceiver Controller
Sensor Controller
MEMCore logic
Power Control
TRANCEIVER
BATTERY
DC-DC
RADIO SENSOR
55
Types of Chemical Weapons
Nerve Agents– Nerve agents attack the bodies nervous system. Nerve agents causse
breathing difficulties, convulsions, paralysis, and death. Nerve agents can be inhaled or absorbed through the skin. Symptoms of nerve agent poisoning include runny nose, tightness of chest, difficulty breathing, excessive sweating, nausea, vomiting dimness of vision, pinpointing of the pupils, convulsion, and death.
Blister Agents– Blister agents attack the lungs, eyes, and skin. They blister both skin and
mucous membranes. Blood Agents
– Blood agents interfere with the bodies ability to absorb oxygen. The victim dies because the body tissues are starved of oxygen. Blood agents cause headaches, vertigo, and nausea before death.
Choking Agents– Choking agents attack the lungs, causing them to fill with fluid. Choking
agents are detected by their smell and their irritancy. The victim suffocates by drowning in his own body fluid. Choking agents cause coughing, choking, tightness of the chest, nasea, headache, and watering of the eyes.
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Common Chemical Weapons
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Choosing power supplies
AA Batteries– Capacity: 650mAh ~ 3135mAh
Button Cells– Capacity: 45mAh ~ 500mAh
88
AA Batteries
Alkaline AA batteries – most common AA battery type. – Pre-charged to 1.5 Volt.– Unsteady voltage. – Capacity: 2,700 to 3,135 mAh. Most AA Alkaline cells offer a
capacity of 2,850 mAh. The expensive Energizer e2 alkaline offer 3,135 mAh and the cheapest cells offer 2,700 mAh, all pretty much alike at low drains. (That's why Consumer Report's testing suggested to get whatever's cheapest).
– Shelf life: some current premium brands exceed 6 years.
99
AA Batteries
Lithium AA batteries– Premium AA battery type. – Pre-charged to 1.5 Volt. – Constant 1.5 Volt over their life. – Capacity: premium brand Lithium AA cells offer around 3,000
mAh, the same as Alkaline.– Shelf life up to ten years, and a longer lifetime than an alkaline
battery. Also retain much better capacity in low temperature (less than 25 °C) than alkaline batteries
– Disadvantage: expensive compared to Alkaline.
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Rechargeable AA batteries – Ni-Cd, Nickel-Cadmium: Capacity: 650 to 1,000 mAh – Ni-MH, Nickel-Metal Hydride: Capacity: 1,350 to 2,500
mAh
AA Batteries
1111
Low Battery Warning Circuit
What would be required is a circuit that constantly monitors the battery voltage, and if it reaches a magic low-point, it gives a signal to CPU. Then the CPU will command the transceiver to send a low battery warning to the base station.
Such a circuit would have to be micro-powered; that is, it draws next to nothing from the battery itself, so it may be left in the circuit continuously without adversely affecting battery reserve.
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CPU Block Diagram
CPU
SENSOR 2
SENSOR 1
TRANSCEIVER
READY1
DATA1
READY2
DATA2
CLOCK RESET
RX_CTRL[1:0]
DATA_IN
TX_CTRL[1:0]
DATA_OUT
ADDR[2:0] RCV_DATA[8:0]
9
DV
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CPU Features Cut-through data path Aggregation of Sensors’ packets Selection of Sensors’ packets “Sleep” cycles, RX “Active cycles”, TX “Active cycles” In-Band Hot reset Support for downstream traffic
– CPU configuration registers programmable wirelessly– Operating system instruction set support– “Send to” node selection capability– “Receive from” node selection capability
Node ID wireless reprogram option Event-Based Queries and Lifetime-Based Queries support
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Transmit Cut-Through Data Path
SENSORTRANSCEIVER
NID[2:0](ADDR[2:0]) RCV_DATA[8:0]
9
DV
Data[5:0]Sync
bit
CPU
Data[5:0]SIDNID[2:0]
Data[5:0]SIDNID[2:0]
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Receive Cut-Through Data Path
SENSORTRANSCEIVER
NID[2:0](ADDR[2:0]) RCV_DATA[8:0]
9
DV
CPU
Data[5:0]NID[2:0]
Data[5:0]Sync NID[2:0]
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Aggregation of Sensors’ packets
SENSOR
TRANSCEIVER
NID[2:0](ADDR[2:0])
CPU
SENSOR
Data1[5:0]SIDNID[2:0] Data2[5:0]SIZE
Data1[5:0]SIDNID[2:0] Data2[5:0]SIZE
Data1[5:0]Sync
bit
Data2[5:0]Sync
bit
Sync
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Selection of Sensors’ packets
SENSOR 1
TRANSCEIVER
NID[2:0](ADDR[2:0])
CPU
SENSOR 2
SIDNID[2:0] Data2[5:0]SIZE
SIDNID[2:0] Data2[5:0]SIZE
Data1[5:0]Sync
bit
Data2[5:0]Sync
bit
Sync
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CPU Configuration Register Access
SIDNID[2:0] Data2[5:0]SIZESync REG
REG_NO[2:0] REG_DATA[2:0]
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CPU Register Map
ADDR Function DATA[2:0] Description
000 NODE ID Data signifies the NODE ID (default value selected using jumpers)
001 TX MODE 100 – TX Cut-through (default)
001 – TX Aggregation
010 – Select (parameter A relevant)
111 – Select (parameter B relevant)
010 RX DUTY 000 – X sec ACTIVE Y sec SLEEP
001 – Z sec ACTIVE N sec SLEEP
….
011 TX DUTY Same as RX DUTY except it applies to transmitter
100 RECEIVER NID Send packets only to the node specified by these 3 bits (111 – reserved for broadcast, 000 – default value for base station)
101 BATTERY LIFE RO register (packet aimed for this register will trigger a transmit packet with BATTERY LIFE information
110 Reserved
111 Reserved
2020
Duty Cycles
RX Duty Cycle (For example: wake up every 30 s for 1 sec)
TX Duty Cycle – Sensor TX side and Transmitter TX side can be decoupled– Transmitter might be turned on only if sensor detects an important
information– Sensor TX side and Transmitter TX side can be turned on at the
same time regardless what data is being sampled
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In-Band Hot Reset
The way to reset the node wirelessly
HOT = 1 signifies the hot reset insertion
The entire packet after the preamble should be all 1’s (packet includes only 1 DATA[5:0] word)
If HOT = 1 but the packet has some 0’s drop the packet - no reset
SIDNID[2:0] Data2[5:0]SIZESync REGHOT
2222
Support for downstream traffic
Capability to program the node from the base station or any other node
Capability to receive OS instructions and digest them
Node recognition capability– “Send to” node selection capability– “Receive from” node selection capability
SENSOR ID
SENDERNID[2:0]
Data1[5:0]SIZESync REGHOTRECEIVER
NID[2:0]Data2[5:0]
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Node ID wireless reprogram option
Node ID is programmed using jumpers (problem: cannot go into the bird’s nest to switch jumpers’ values) or using the default factory setting or using EPROM (EEPROM) etc…
Solution: Wireless ability to reprogram the default value
SENSOR ID
SENDERNID[2:0]
Data1[5:0]SIZESync REGHOTRECEIVER
NID[2:0]Data2[5:0]
Default value
Config reg
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Event-Based Queries support
Event-Based Query is the way to program the node to send the data acquired only if the programmed parameters are met
– ON EVENT bird-detect (loc)SELECT AVG (light), AVG (temp), event.locFROM sensors AS s WHERE dist (s.loc, event.loc)SAMPLE INTERVAL 2 s for 10 s
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Lifetime-Based Queries support
Lifetime-Based Query is the way for user to program the query duration in days, weeks or months.
– SELECT nodeid, accel– FROM sensors– LIFETIME 30 days
(Note: we do not plan to have day/month/year precision but rather permanent sampling, no sampling, even-based sampling, short-period sampling)
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Questions from the Proposal Presentation (1)
Internal tri-state buffer use?– Internal tri-state buffers is not planned to be used. We plan to
use simple multiplexers instead.
If receiver is asleep how are you going to get the data?– We will have to make sure that the receiver is awake at the
right point of time (synchronization needed, programmability support provided by our CPU)
How do you distinguish 2 sensors if you use the same 3-bit addr for both?
– Sensor ID field is used to distinguish among sensors.
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Questions from the Proposal Presentation (2)
How do you decide whether to send data or not?– Configuration registers provide the ability to decide the
operational mode. They will drive decisions when to sample/send data.
Run the CPU fast, sample quick, power down, go to sleep in between samples. Saves Power!
– We will research more on this one. At this point we are not sure that with the faster clock we will save power.
Is there a common power source between CPU/sensors/transceiver?
– Yes and most likely it will be 2 AA batteries.
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