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Photonics module planning

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Guy Fraser edited this page Jul 28, 2017 · 13 revisions

Risks

  • Hyperspectral camera could be prohibitively expensive
  • Heliotrope could be unreliable
  • Heliotrope motors might consume far too much power
  • Hermetic sealing means there's no easy way to vent excess heat

Casing

Must be hermetically sealed with space for silica gel bag.

  • Optically transparent dome
    • Hydrophobic coating on outside
    • Must be lightweight (for drone use) but strong enough to withstand hailstone or similar impacts
  • White ASA plastic sheath (affix dome to base)
    • Rubber seal at bottom, presses down on dome lip
    • Some slots cut in it for sensors on outer rim
    • Might have some solar cells?
  • White ASA plastic base
    • Rubber seal at top, dome lip rests on it
    • Wires need routing through bottom to module below; must be hermetically sealed

PCBs

  • Outer rim - a ring around the inside of the dome
    • Contains fixed-position sensors (which must be long-term UV stable)
  • Heliotropic platter - circular disc that sits on top of heliotrope
    • Possibly aluminium
    • Solar cells and some sensors on top
    • Circuitry for camera underneath + more solar cells
  • Camera board
    • hyperspectral camera
    • possibly FPGA on reverse?)
  • Heliotrope controller - controls stepper motors; might be merge in to platter

Harvesting

  • Solar cells on heliotropic platter
  • Potentially solar cells on plastic sheath
  • Potentially any inactive LEDs and sensors
  • Potentially peltier/seebeck device (if required for cooling module, when not in use)

Mechanical

The heliotrope consists of three motors (pan, tilt, pedestal) to rotate the platter that is fixed on top of it:

  • Pan: 360º – maybe little more?
    • Must not continually rotate; prevent wires over-twisting
  • Tilt: -45º to +90º
    • -45º to 0º – angle main solar cells at sky
    • 0º – resting position; horizontal
    • 0º to 90º – for camera work
  • Pedestal: 0mm to ??mm
    • 0mm – platter level with outer rim; camera in rest position; protects from longterm UV
    • ??mm - camera has clear view of horizon

If optional lenses are implemented, additional motors will be required for those.

If zoom feature is implemented, one tiny motor will be required for that.

Components

Outer rim top:

  • fire detection (flagrometer)
  • lightning detection (fulmenometer)
  • detonation detection (bhangmeter)
  • could detection (oktameter)
  • Rainlight sensor
  • Ambient/UV
  • UVA/UVB
  • LEDs: IR, Vis

Outer rim bottom:

  • Micro UX2 connector

Heliotropic platter top:

  • 2-4 x solar cells
  • 3 x directional light sensors? (to allow auto-adjust when solar harvesting)
  • pyranometer (GHI)

Heliotropic platter bottom:

  • Connector for camera board
  • Possibly heliotrope controller (see later)?
  • Possibly interim energy storage?

Camera board front:

  • Hyperspectral camera
    • diluculumphotometer (twilight photometer)
    • heliophotometer -- potentially a separate sensor on outer rim?
    • heliospectrometer
    • infragrammeter
    • nitorometer
    • thermograph
    • sunphotometer / Solar Spectral Flux Radiometer
  • pyrheliometer (DNI with collimator)
  • Rangefinder

Camera board back:

  • Possibly FPGA?
  • Connector socket?

Heliotrope controller:

  • Might be merged in to platter (bottom side)?
  • 3+ Stepper motor controllers (at least 12 wires)
  • Probably want optical feedback for micro-adjustments whilst solar harvesting
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