• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
CAPE Buoy
 

CAPE Buoy

on

  • 1,746 views

University of Louisiana at Lafayette Senior Design Project

University of Louisiana at Lafayette Senior Design Project

Statistics

Views

Total Views
1,746
Views on SlideShare
1,739
Embed Views
7

Actions

Likes
1
Downloads
11
Comments
0

2 Embeds 7

http://mtnbikingmanimal.blogspot.com 5
http://www.slideshare.net 2

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

CAPE Buoy CAPE Buoy Presentation Transcript

  • Members: John DeBlanc Elias Ellsworth Peter Bankole Luis Chinchilla Mentors: Nick Pugh Mark Fenstermaker Satellite Communications Buoy Senior Design II Fall 2008
  • Outline
    • Introduction
    • Purpose
    • Functional Specifications
    • High Level Block Diagram
    • Introduction to Buoy System Model
    • Satellite Access Scheme
    • Data Budget
    • Sensor Subsystem
    • Link Budget
    • Communications Subsystem
    • Power Budget
    • Power Subsystem
    • Onboard Computer
    • Mechanical Subsystem
    • Summary
    • Acknowledgments
  • Introduction
    • This design project will develop a satellite communications buoy.
    • This buoy will communicate with a Low Earth Orbiting (LEO) CubeSat; namely, the C.A.P.E. II
    • This project will combine the desirable features of satellite communications and low power requirements for future buoys and other remote applications.
  • Purpose
    • Gather environmental data and then upload it to the C.A.P.E. II.
    • Demonstrate the usefulness of CubeSats in the area of data collection and forwarding.
    • Create a new arena for opportunities and applications within the CubeSat community.
    • Open doors for future University of Louisiana at Lafayette senior design teams that could develop other terrestrial applications with satellite link functionality.
  • Functional Specifications Environment Large Body Of Water Potentially Harsh Weather Buoy Compatible w/ Naval Academy Buoy On-board GPS Receiver Memory > 100 Megabits Data Interface (I2C) Low Cost 4) Sunlight 1) Environmental Data 2) Location 3) Time 5) Satellite Commands Inputs 1) 145MHz and/or 435MHz Transmission Frequency 2) Sufficient Transmission Power To Close Link With CAPE2 3) Transmit Location, Time, and Environmental Data Outputs Power System Solar/Batteries
  • High Level Block Diagram TX TX RX RX Sensors GPS PIC External Memory Solar Cells Batteries Power System TNC Radio Mechanical PVC Structure
  • Buoy System Model Data Budget How much data is collected? Comm. Budget How much signal is needed? Power Budget How much power is required?
  • Satellite Access Scheme Beacon Buoy “ Aloha?” Beacon "aloha" every 4 minutes. If acknowledged by satellite, upload weather data. Wait 24 hours until next satellite contact attempt. Satellite
    • The buoy will measure 8 environmental variables plus GPS location and time
    • If the buoy measures these variables 24 times a day, we collect about 1.4kilobytes
    Data Budget
    • Anemometer
    • Compass
    • Water Temp
    • Humidity
    Sensors
    • Wind Vane
    • Air Temp
    • Pressure
    • Salinity
    • The wind speed would be detected using
    • 3 cups anemometer assembly and
    • a 0H090U Hall Effect Transistor
    • The 3 cups anemometer assembly as a magnet in its center. The magnets would be used to detect the rotations of the cups.
    • Calculation
    • v(m/s) = 2*pi*f ( r )
    • r = radius from center of shaft to
    • center of cups.
    • r = 0.053mm
    • v = velocity in meters/sec
    Anemometer
    • The wind vane includes a 5k Dual Wiper
    • Potentiometer which uses a 540 degree
    • format and analog input range – 0 to 5V
    • It would also include a tail and a pointer that would point in the direction of the wind. The Tail and the pointer will help rotate the potentiometer to the direction of the wind.
    • A 3 Axis digital Compass (TTL) is used
    • to orient the wind direction to its true
    • north
    Wind Vane
    • Features:
    • - Azimuth
    • - Inclination (Pitch and Roll)
    • - 3 Axis magnetic sensors from Honeywell
    • - 3 Axis Accelerometers(G) from ST Microelectronics
    • - 24 bit differential Analog to Digital Converter from Analog Devices
    • - Four sentence formats for data parsing
    • - Tera Terminal software for COM
    • - Multiple baud rate(4800, 9600, 14400, 192000, 38400, 57600, 115200)
    • - Built in Temperature Sensor (-40C to 85C) for compass board
    (0S500-T) 3 Axis Compass (TTL)
    • A DS1621 DIP Temperature Sensor
    • is used to determine the air temperature sensor. It ranges from -55C to 125C and it uses I2C communication bus to communicate with a data handling system
    • The DS1621 is placed inside a non- conducting epoxy for the water temperature Sensor
    Air / Water Temperature Sensor
    • The humidity of the air would be detected using dry and wet bulb thermometers
    • The humidity is calculated based on a comparison between the wet bulb temperature and the dry bulb temperature. This method is used for some psychrometers.
    Humidity Sensor
    • The MPX4115AP Pressure Sensor would be
    • used to measure air pressure. It ranges from
    • 15 to 115kpa
    • A 0.17 ID, 0.25 OD POLYETH TUBE would used as an atmospheric vent
    Pressure Sensor
    • Requires two electrodes mounted
    • inside PVC
    • Uses IRF7831 MOSFET Switch to
    • turn on sensors
    • MAX4372 Op. Amplifier for voltage
    • Output: 0 to 5v range for ADC
    • conversion
    • The salinity would be determined by
    • finding a relationship between the
    • voltages and salinity through a graph.
    • A mathematical formula would be
    • derived from the graph because the
    • voltages are proportional to the
    • salinity
    Salinity Sensor
  • Link Budget
  • Communications – Link Testing ¼ Wave Antenna – 6W TX Power Naval Academy LEO PCSAT Antenna Polarization
  • Low power 3V Radio Handheld Radio Picopacket TNC-X Communications - Radio
  • Power Budget
    • How did we go about designing the Power Subsystem?
    Total System Power Units Amount Total Onboard Computer Power PER DAY Watt-hours 0.3685176 Total Communication Power PER DAY Watt-hours 3.7863978 Total GPS Power PER DAY Watt-Hours 0.48 Total Sensor Power PER DAY Watt-Hours 0.1277 General System Power PER DAY Watt-hours 4.7626154
  • Power – Power Subsystem
    • Batteries vs. Solar Panels + Batteries:
      • Batteries have a limited lifetime.
      • Solar panels will provide a longer lifetime to batteries to satisfy the buoy’s power needs.
    • Sealed Lead Acid Battery
      • Poor weight-to-energy density
      • Inexpensive
      • Low-self discharge
      • Multiple Solar Panels
        • Collect as much sunlight as possible
  • Power – Experiments
    • Peak Power Point
      • Use solar panels efficiently
      • Different Peak Power Points
          • Generic vs. Atlantic
          • Which one is better?
    Generic Atlantic
  • Power – Experiments Generic Atlantic Typical Voltage Volts 14.75 Typical Current Amps 0.09499 Typical Power Watts 1.40110 Time In Sun Per Day Hours 3.3 Power Per Day / Panel 1 (Direct Sunlight) AH 0.313467 Power Per Day / Panel 1 (Direct Sunlight) WH 4.62363825 Indirect Sunlight Percentage % 20.00% Power Per Day / Panel 2 (Indirect Sunlight) AH 0.0626934 Power Per Day / Panel 2 (Indirect Sunlight) WH 0.92472765 Indirect Sunlight Percentage % 20.00% Power Per Day / Panel 3 (Indirect Sunlight) AH 0.0626934 Power Per Day / Panel 3 (Indirect Sunlight) WH 0.92472765 Indirect Sunlight Percentage % 10.00% Power Per Day / Panel 4 (Indirect Sunlight) AH 0.0313467 Power Per Day / Panel 4 (Indirect Sunlight) WH 0.462363825 Total Power Generated Per Day (Amp-hours) AH 0.362054385 Total Power Generated Per Day (Watt-hours) WH 5.340302179 Typical Voltage Volts 12.65 Typical Current Amps 0.06235 Typical Power Watts 0.78873 Time In Sun Per Day Hours 3.3 Power Per Day / Panel 1 (Direct Sunlight) AH 0.205755 Power Per Day / Panel 1 (Direct Sunlight) WH 2.60280075 Indirect Sunlight Percentage % 20.00% Power Per Day / Panel 2 (Indirect Sunlight) AH 0.041151 Power Per Day / Panel 2 (Indirect Sunlight) WH 0.52056015 Indirect Sunlight Percentage % 20.00% Power Per Day / Panel 3 (Indirect Sunlight) AH 0.041151 Power Per Day / Panel 3 (Indirect Sunlight) WH 0.52056015 Indirect Sunlight Percentage % 10.00% Power Per Day / Panel 4 (Indirect Sunlight) AH 0.0205755 Power Per Day / Panel 4 (Indirect Sunlight) WH 0.260280075 Total Power Generated Per Day (Amp-hours) AH 0.237647025 Total Power Generated Per Day (Watt-hours) WH 3.006234866
  • Power – Regulating Power
    • Step-down voltage : 12 V to 5 V
    • Linear Regulator vs. Switching Regulators:
    • Linear :
    • Take the difference between input and output voltages.
      • Difference voltage is converted into thermal energy  Wasted as heat
      • Efficiencies: 14% to 40%
    • Switching :
    • Takes small amounts of energy from input voltage and moves it to output.
      • Relatively small energy loss.
      • Efficiencies: 70% to 85%
      • Conclusion :
        • Switching Regulator Efficiency > Linear Regulator Efficiency.
  • Power – System Features
    • -Controlled Solar Charging
    • -Prevent solar panels from overcharging batteries
    • -Using a MOSFET as a switch between solar panels and batteries
    • -Microcontroller will open / close switch depending on battery charge
    • -Control Other Subsystem’s Power
    • - Some components will not be used all the time.
    • - Use of MOSFETs as switches to selectively power buoy components
    • -Watchdog Timer
    • -Resets the Microcontroller
    • -Momentarily cuts the power to the Microcontroller and Subsystems
    • -Reset a latch up condition
    Battery D G Solar Panel S
  • Power – Final Calculations
    • Despite conservative assumptions about sunshine per day and system inefficiencies this power system design exceeds the buoy's power requirements.
    Total System Power Units Amount General System Power PER DAY Watt-hours 4.7626154 Solar Power Harnessed PER DAY Watt-hours 5.340302179 Surplus Power From Sun Watt-hours 0.577686779
  • Onboard Computer Coordinating the Subsystems Sensors Power Comm Satellite Communications Weather Buoy
  • The Buoy State Machine
  • Data Gathering State Fetch current data from the environmental sensors and GPS
    • struct ENVIRONS* GetEnvirons();
    • Pressure (kPa), Humidity (%), Air Temperature (degrees),
    • Water Temperature (degrees), Salinity (mg/L),
    • Wind Speed (mph), and Wind Direction (N,S,W,E,NE,NW,SE,SW)
    • struct GPS* GetGPS();
    • Time , Longitude , and Latitude
  • Aloha State Attempt to contact satellite Acknowledged Not Acknowledged
  • Data Tx State Upload environmental data to satellite [Buoy Address],[Date],[Time],[Latitude],[Longitude],A[Air Temperature],W[Water Temperature],H[Humidity],WS[Wind Speed],WD[Wind Direction],S[Salinity] 03,101809,053021.32,2501.23.N,9002.18.W,A088,W084,H060,WS015,WDNW,S32
  • Wait Short State Waiting between data gathering and alohas 60 Minutes 4 Minutes
  • Wait Long State Waiting while accumulating a 24 hour data set 60 Minutes 24 Hours
  • Power Management State Disable Solar Charging Enable Solar Charging Low Power Mode Cease Activity Until Voltage >= 12.4 100% Charge 80% Charge 30% Charge Regulate System Voltage
  • Mechanical - Construction Bending PVC for Solar Panel Mounts Final Result
  • Mechanical Antenna Solar Panels 3 ft Discus Aluminum Struts Payload
  • Mechanical - Stability Test Insert Video Here
  • Sensors Physical Mount
  • Summary
  • Acknowledgements
    • Special Thanks to:
      • Nick Pugh
      • Mark Fenstermaker
      • Fenstermaker and Associates
      • Dr. Zhongqi Pan
  • Questions ?
  • Appendix
    • Satellite Data Transmission
    • Salinity Testing Schematic
    • Power Subsystem Schematic
    • Sensors Subsystem Schematic
    • Main Board Schematic
    • Angle of Incidence
    • Buoy System Model Spreadsheet
    • Communication Subsystem Schematic
    • TNC - X Schematic
  •  
  • Satellite Data Transmission
  • Satellite Data Transmission
  • Satellite Data Transmission
  • Satellite Data Transmission
  • Satellite Data Transmission
  • Satellite Data Transmission
  • Satellite Data Transmission
  • Salinity Testing Schematic
  • Power Subsystem Schematic
  • Sensors Subsystem Schematic
  • Sensors Subsystem Schematic
  • Main Board Schematic
  • TNC- X Schematic
  • Angle of Incidence
  • Buoy System Model
  • Buoy System Model
  • Buoy System Model
  • Buoy System Model
  • Buoy System Model
  • Buoy System Model
  • Buoy System Model
  • Buoy System Model
  • Buoy System Model
  • Communications Subsystem Schematic
  • Transistors
    • Bipolar Junction Transistors vs. Field Effect Transistors:
    • BJT :
    • Works by injecting electrons into the “Base”
        • Trigger that turns the transistor on / off
        • Thus, they require current to flow in order to keep transistor working
    • FET :
    • Voltage applied to the Gate controls the current flowing in the Source-Drain channel
      • No more current is needed to keep transistor closed for the duration of time needed
      • Conclusion :
        • BJTs are current-controlled valves & FETs are voltage-controlled valves.
        • Loss in power of a FET < Loss in power of a BJT.
  • Transistors
    • Bipolar Junction Transistors vs. Field Effect Transistors:
      • Conclusion :
        • BJTs are current-controlled valves & FETs are voltage-controlled valves.
        • Loss in power of a FET < Loss in power of a BJT.
  • Regulators
    • Linear Regulator vs. Switching Regulators:
    • Linear :
    • Take the difference between input and output voltages.
      • Difference voltage is converted into thermal energy  Wasted as heat
      • Efficiencies: 14% to 40%
    • Switching :
    • Takes small amounts of energy from input voltage and moves it to output.
      • Relatively small energy loss.
      • Efficiencies: 70% to 85%
      • Conclusion :
        • Switching Regulator Efficiency > Linear Regulator Efficiency.
  • Solar Panel Efficiency
  • Voltage Scalar
  • S D G V GS MOSFET as a Switch
    • -Regions of Operation:
    • -Cutoff Region
    • -Triode Region
    • -Saturation Region
    • -For a Switch: Cutoff and Triode Regions are utilized.
    • -Cutoff occurs when  V GS < V T
    • - Device is turned off
    • -Triode occurs when  V GS > V T and V DS < V GS – V T
    • -Device is turned on
    • -V T is the Threshold voltage
    • -Established during device fabrication
    • -Typically lies between 0.5 V – 1.0 V
    • -MOSFET acts as a linear device:
    • -Linear resistor whose resistance can be modulated by changing V GS .
    V DS Solar Panels Driver
  • High-Side Driver
    • -Essentially a specialized power amplifier
    • -Connected Between:
    • -Output of a Power Supply Controller  Microcontroller
    • -Power Switch it is driving  MOSFET
    Solar Panels Driver PIC S D G V GS
  • Charging Batteries