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Micro Weather Systems - MWS

GOOD MORNING !

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Micro Weather Systems - MWS

Who Are We?

•Clint Lee

•John Crankshaw

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Micro Weather Systems - MWS

Why are we here?

Contracted by Design Co, Ltd.

Of 

San Diego

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Micro Weather Systems - MWS

What are we doing?

Designing and Manufacturing a

Compact – Low Cost – Rugged

Weather Station

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Design Goals and Constraints

•Compact

•Easily Installed

•Extended Deployment – 90 to 120 Days

•Low Cost

•Rugged

Weather Station Requirements:

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Weather Station

• Atmospheric Pressure

• Temperature

• Relative Humidity

• Wind Speed

• Wind Direction

• Rain Fall

What Weather inputs do we monitor?

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Conceptual Diagrams

12'’

4'’

Solar Panel

0.5'’

2'’

Drain Hole

Vent Slits

12'’

4'’

Solar 

Panel

Rain Funnel

Rain Tipping

Bucket

2'’

Drain

Batteries

Flex Sensors

PCB

PressureSensor 

Humidity and

Temp Sensor 

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Functional Diagram

Sensirion SHT15 Humidity

and Temperature Sensor 

Digital 2-wire serial

interface.

Supply Voltage: 2.4V-5.5V

Supply Current(Avg): 28µA

Wind Sensor 

(Flex Sensors)

Differential voltage output

Supply Voltage: 3VSupply Current: TBD

Rain Sensor 

(Tipping Bucket)

Output TBD

Supply Voltage: TBD

Supply Current: TBD

IC Sensors Model 1451

pressure sensor.

Differential voltage output.Supply Voltage: 3V-12V

Supply Current: 0.6mA

 A/D Converter Processing Unit

Memory

Serial I/O

Solarbotics SCC3766

Solar Cells x 3

6.7V @ 30mA

NiMH 1.2V ‘AA’ cell

batteries

3 in series.

RS-232

Interface

MCU: ATmega644P

Dallas Maxim DS1302

Real-Time Clock

Digital 1-wire serial

interface

Supply Voltage: 3V

Supply Current: 200nA

Citizen

CFS206

32.768kHz

Crystal

External Flash Memory

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Accomplishments

Completed Tasks in Weather Station Project

•MCU Selection – ATMEL ATMEGA644P

•Serial Flash Programming via SPI bus.

•Schematic Capture of MCU sub-system

•Initial proto-board layout of MCU sub-system

Micro-controller Activities

Sensor Activity

•Temp & Humidity PCA designed and Fab’d

•Pressure Sensor PCA designed and Fab’d

•Wind Sensor Mock up and Calibration Testing

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Microcontroller-Schematic

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Microcontroller-Layout

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Proto-Type MCU

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Wind Sensor Testing

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Sensor Update

Pressure Sensor PCA Temp & Humidity PCA

Solar Cell Assembly

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Project Timeline

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Budget Update

Original Budget

Commercially Available Parts:Temperature and Humidity sensor $ 28.95Pressure sensor $ 23.40Real-Time clock $ 4.13Crystals $ 0.28Flex sensors $ 64.75MCU $ 7.76Flash memory $ 3.48Instrumentation amplifiers $ 9.30Solar array $ 22.00Batteries $ 27.00

 Assorted resistors and capacitors $ 5.00Fabricated Parts:

Plastics (wind sensor) $ 5.00Plastics (rain sensor) $ 5.00

 Assorted parts $ 10.00Housing:

PVC $ 10.00Silicone sealant $ 5.00

Total:$ 231.05

Current Expenditures

Commercially Available Parts:Temperature and Humidity sensor $ 28.95Pressure sensor $ 23.40Real-Time clock x 2 $ 8.26Crystals x 2 $ 0.56Flex sensors x 5 $ 64.75MCU $ 7.76Flash memory $ 3.48Instrumentation amplifiers $ 0.00Solar array $ 10.99Batteries $ 0.00

 Assorted resistors and capacitors $ 0.00Fabricated Parts:

Plastics (wind sensor) $ 2.00Plastics (rain sensor) $ 0.00

 Assorted parts $ 10.00Housing:

PVC $ 0.00Silicone sealant $ 0.00

Total: $ 160.15

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Development Activities

Current Project Development Activities

Micro-controller development activities

Sensor development activities

•MCU – Serial Interface code

•MCU – RTC Interface code

•MCU – Temp & Humidity code

•Tipping Bucket sensor implementation – Hall-Effect

•Wind Speed Sensor  – calibration and implementation

•Pressure Sensor amplifier circuit

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Conclusion

12'’

4'’

Solar 

Panel

Rain Funnel

Rain Tipping

Bucket

2'’

Drain

Batteries

Flex Sensors

PCB

Pressure

Sensor 

Humidity andTemp Sensor 

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Micro Weather Systems - MWS

Question and Answers

Further Inquiries can be made by emailing:

Clint Lee clee@mws.sdsu.edu

John Crankshaw  jcrankshaw@mws.sdsu.edu

Or Visit our Website:

http://mws.sdsu.edu

Thank You For Your Time!