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Design, Modeling, and Capacity Planning for Micro-Solar Power Sensor Networks. Jay Taneja , JaeinJeong , and David Culler Computer Science Division, UC Berkeley IPSN/SPOTS 2008 Presenter: SY. Outline. Introduction Micro-Solar Planning Model And System Design Node And Network Design - PowerPoint PPT Presentation
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Network and Systems Laboratorynslab.ee.ntu.edu.tw
Design, Modeling, and Capacity Planning for Micro-Solar Power Sensor Networks
Jay Taneja, JaeinJeong, and David CullerComputer Science Division, UC Berkeley
IPSN/SPOTS 2008
Presenter: SY
Network and Systems Laboratorynslab.ee.ntu.edu.tw
OutlineIntroductionMicro-Solar Planning Model And System
DesignNode And Network DesignEvaluationConclusion
Network and Systems Laboratorynslab.ee.ntu.edu.tw
MotivationThey have a project – HydroWatch
Study hydrological cycles in forest watersheds
Sense temperature, humidity, and light
Forest environmentWant to design a device
Sense and transfer dataSolar powered
Infinite power lifetime
Network and Systems Laboratorynslab.ee.ntu.edu.tw
About This PaperShow how they develop the micro-solar
power subsystem -- systematicallyModeling DesignEvaluation
System design experience sharingReal deployment evaluation
Network and Systems Laboratorynslab.ee.ntu.edu.tw
The ChallengesCapacity Planning
Infinite power lifetime
Mechanical DesignWeatherproof with Correctly Exposed Sensors
Incorporating off-the-shelf and custom-built pieces
Network and Systems Laboratorynslab.ee.ntu.edu.tw
OutlineIntroductionMicro-Solar Planning Model And System
DesignNode And Network DesignEvaluationConclusion
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Storage Charge-Discharge 72:1120:1240:11:1All Ideal Components 48:1Half Hour of Exposure Per Day
Micro-Solar Planning Model
Regulator EfficienciesE in : E out
66%
2%
60%
50%
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Application LoadStarting point for capacity planningMost time is spent sleeping (~20 uA) with short
active periods (~20 mA)
Device Average CurrentSensors 9 uA (550 uA at 1.67% DC)Radio 0.206 mA (20.6 mA at 1% DC)MCU 9.6 uA (2.4 mA at 0.4% DC)Quiescent 15 uATotal 0.24 mA (supply voltage 3.3V
79.2mWh)
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Energy StorageType Lead
AcidNiCad NiMH Li-ion Superca
pOperating
Voltage Range5.0-6.1V 0.8-1.35V 0.9-1.4V 3.0-4.2V 2.2-3.0V*
Volume Energy Density
67 Wh/L 102 Wh/L 282 Wh/L 389 Wh/L 5.73 Wh/L
Charge/Discharge Efficiency
70-92% 70-90% 66% 99.9% 97-98%
Self-discharge (Per Month)
3-20% 10% 30% <10% 5.9%/day
Charging Method
Trickle Trickle/Pulse
Trickle/Pulse
Pulse Pulse
Est. Lifetime (79.2 mWh/day)
98.5 days 33.3 days (2)
75.8 days (2) 35.4 days 3.8 daysStraightforward charging logic
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Solar PanelSolar cells composition
In serial and parallel
The panel characterized by its IV curveOpen-circuit voltage, short-circuit current, and
maximum power point
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Solar PanelImportant parameters
IV and PV CurvesPhysical Dimensions
MPP: 3.11 Volts
They choose – Silicon Solar #16530 (4V-100mA)
Network and Systems Laboratorynslab.ee.ntu.edu.tw
RegulatorsRegulators are “glue” matching primary
components50-70% efficiency for typical sensornet load
rangeInput regulator
Regulates voltage from solar panel to batteryCan be obviated by matching panel directly to
storageOutput Regulator
Regulates mote voltageProvides stability for sensor readingsModel estimates that load requires 28 minutes of
sunlight
Network and Systems Laboratorynslab.ee.ntu.edu.tw
OutlineIntroductionMicro-Solar Planning Model And System
DesignNode And Network DesignEvaluationConclusion
Network and Systems Laboratorynslab.ee.ntu.edu.tw
HydroWatch Weather Node
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Mechanical ConsiderationsEnclosure design is often application-driven
Sensor exposureWaterproofingEase-of-DeploymentRF in forestInternal mechanicals
Temp / RH Sensor TSR, PAR Sensors
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Network Architecture
Used Arch Rock Primer Pack for multi-hop network stack, database for stored readings, and web-based network health diagnosis
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Forest Deployment
Network and Systems Laboratorynslab.ee.ntu.edu.tw
OutlineIntroductionMicro-Solar Planning Model And System
DesignNode And Network DesignEvaluationConclusion
Network and Systems Laboratorynslab.ee.ntu.edu.tw
The Urban Neighborhood20 Nodes for 5 Days
Mounted on house, around trees, and on roof
Meant to emulate forest floor conditions
Important for systematic approach -- provided validation of model
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Urban Neighborhood Energy Harvested
Every node received enough sunlight
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Three Nodes, Three Solar Inputs
Network and Systems Laboratorynslab.ee.ntu.edu.tw
The Forest Watershed19 Nodes for over a MonthMounted on 4-ft stakes throughout the area
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Forest Watershed Site
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Forest Watershed Energy HarvestedWatershed
Most nodes struggle to
harvest sunlight
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Three Nodes at the Watershed
Network and Systems Laboratorynslab.ee.ntu.edu.tw
Reflected Light
Though only minimally, a cloudy day helps a sun-starved node harvest solar energy.
Sunny
Overcast
Overcast
Sunny
Network and Systems Laboratorynslab.ee.ntu.edu.tw
ConclusionAlways surprises in real environmentReliability is important real application
But difficult to achieveIn their work
Systematic approach resulted in 97% collection of an unprecedented spatiotemporal data set
System design experience sharing
