The Sunstrap

The idea:
Manufacture a neckstrap that absorbs power from the sun and converts that energy into a trickle charge for rechargeable batteries.

How:
Wire forty–eight, 4–volt, 100 microamp solar cells onto a neckstrap in parallel with twenty 0.4–volt, 1.8 milliamp solar cells to provide a trickle charge to a pair of rechargeable AAA batteries. Depending on the limitations of the circuitry and the aesthetic of a rough draft, I may include foldable solar cells.

The Process

Specifications

• Weight: The entire strap, including a pair of 900mAh, AAA batteries weighs 56.69 grams (2.0 ounces)
• Spacing: Each "Solar Chip" is spaced at about 15mm (6/10ths of an inch) from each other
• Voltage: Under direct artificial light, The Sunstrap yields about 4.0 volts of DC power; under fluorescent light, about 2.1 volts; and, under room lighting, only about 0.6 volts
• Length: The length of the strap from the entry point on the right side of the pendant to the entry point on the left side is 35 INCHES. (This measurement was taken along the inner periphery of the Solar Chips.)
• A 1N4004 diode was placed at the battery level to avoid having the batteries reverse charge current under low light conditions.
• Strap:
• Pendant:
• Measurements
  • Chip: x × x
  • Pendant: x × x

Datasheets

• Clare CPC1824 (pdf)
• OSRAM BPW 34 (pdf)

todo (sunstrap)
. clear up synopsis
. spec sheet for the CPC1824
. discuss the design and building of my own parts control boards
. discuss etching my own boards
. put up the eagle sketches . add spec sheets for all parts . put up the images.