Saturday, September 17, 2011


  • Solar cells
    • Function: Produce a current through coiled COPPER WIRE, to spin a shaft with MAGNETS on it to wind up a SPRING.
    • Constraints
      • Need to pick a cell which either independently, or wired together, puts out proper voltage for arduino and minimal switching. Also charge battery(s) to operate through night.
      • mA: sufficient to charge battery to ideal capacity for night operation (mA * 6 hours?)
    • Possibilities (
      • 1V 415mA 60mm x 60mm x 2.8mm $3.90 25+ $3.60
      • 2V 80mA 58mm diameter circle $1.90 25+ $1.70
      • 9V 70mA 85mm x 69mm x 2.5mm $6.90 25+ $6.40
  • Batteries:
  • Magnets:
    • Function
      • Day: respond to current in coil to rotate shaft, winding up spring
      • Night: produce current in coil, winding
    • Constraints
      • size, power (n48? n52?) volume of magnet * strength would presumably affect how much charge is created, or how much the shaft spins in response to the current.
    • Possibilities
  • Spiral Torsion Spring
  • Arduino
    • Function
      • Night: sense body/movement/heat(pick 1) below widget
        • IF true, THEN close switch, completing circuit, providing power to actuate pawl to release so that ratcheted spring can unwind X seconds, spinning shaft, producing current in coil
      • Day: sense voltage from solar cell
        • IF V < min. operating voltage + 1, THEN flip (H-switch?) switching power circuit from solar cell to battery

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