GPS Crop Dusting

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GPS Crop Dusting

• Laurel Steichen
• Gau Bodepudi
• Senior Design Final Presentation
• April 29, 2002

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Introduction

• Goal To track a crop dusting plane from a base
  station in real time utilizing a GPS satellite
  system and enable/disable its spraying
  capabilities based on the type of land it is
  flying above

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Introduction

• Applications
• Improve efficiency and allocation of spraying
  chemicals
• Can be extended to monitor and track multiple
  airplanes and manipulate specific functions
• Possible counter-measure to terrorism

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Original Design

• Through the GPS system, the base station will
  track the crop dusting plane in real time
• The land use of any given latitude and
  longitudinal position is coded into the software
• If the plane is above a crop zone area, then the
  sprayers are enabled

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Original Design

• If the plane is not above a crop zone area (ex.
  urban area or a body of water) the sprayers are
  disabled

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Our Project

• We preprogrammed a map matrix into the memory of
  a microcontroller (Motorola HC12) and made a
  serial connection to a portable GPS unit (Garmin
  12XL)
• The map is divided into spray and no-spray
  zones
• The microcontroller reads the current position
  from the Garmin unit

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Our Project...

• If the position is in a spray zone, then it
  powers a relay circuit

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Sub-Projects

• Communication with Garmin GPS 12XL
• Programming of HC12 Microcontroller
• Hardware simulation of the sprayer unit

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GPS
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Garmin GPS Unit

• Portable GPS system
• Displays current position, direction, altitude
  and speed
• Displays satellite positions and strength of
  satellite signal
• Has serial communications port to communicate
  with computer

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Communications
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Programming of Micro

• Map matrix was programmed into memory
• Took GPS system and recorded the latitude and
  longitude of four points that surrounded the
  university

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Programming of Micro

• Those four points used to make an enclosed grid
  --gt two possible areas inside or outside the
  grid

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Hardware simulation of Sprayer

• In order to turn on and off sprayer, 7 booms had
  to be turned on and off simultaneously
• After consulting with engineers from Raven
  Industries, we found that we could simulate the
  sprayer circuit control through a 12V relay
  circuit
• The output of the micro was 5V ? we needed to
  step up the voltage

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Hardware Simulation of Sprayer

• That was accomplished by using a common collector
  BJT configuration
• After the voltage is stepped up, it is fed into a
  reed relay

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Hardware Simulation of Sprayer
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Challenges

• Biggest challenge was the project change in the
  middle of the semester
• A lot of our work went into preparing for a
  completely software oriented project that used
  another GPS system
• Learning assembly
• Circuit worked in the lab, but not when testing
  it on the road

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Challenges

• Discrepancy between the position shown on the
  portable unit display and the position displayed
  on the hyperterminal of the computer that the GPS
  unit was connected up to
• not sure if our boundaries were correct and if we
  even crossed over when testing our circuit on the
  road

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Successes

• We successfully managed to complete the project
• It worked in the lab when we put the entire
  system together

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Recommendations

• This can be easily applied to a more
  sophisticated GPS system
• More versatile because different color coded maps
  can be easily loaded into the software
• Can be extended over a larger area as well
• Addition of a security system

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Questions?