Web site created by Donato Borello, Amsal Karic, and Randal C. Nelson

-Final Product-

The end of the semester brought a bit of a rush as the teams worked to complete and assemble the different components. Despite our efforts at modularization, a considerable amount of back and forth interaction between the teams was needed as various constraints that were not obvious at the outset became manifest. In retrospect, effective communication within and between teams was one of the greatest challenges we encountered.

The most notable emergent constraint was the limitations of the photocells, which do not deliver anything approaching the rated power and voltage in ordinary lighting conditions. The ratings are derived from ideal, direct solar models, which we never actually observed in the field. Since we wanted the device to harvest energy in ambient room lighting, we ended having to deal with power and current levels three orders of magnitude below initial good-case estimates. Most of the components we first envisioned using would not operate at the power levels available, even to store up energy for later use, forcing a complete redesign. The power and electronics teams ended up working as a unit to resolve these issues.

Final assembly was rushed. Properly sealing the artifact required a series of operations where sealing materials had to cure several hours at a number of separate stages. Rather than commit to a poor final product, the working components were assembled dry, and delivered to professor Nelson who had time to carry out final fitting and sealing of the artifact.

The four teams and group contributions were:

  • Housing -- Durable copper-aluminum alloy metal box with transparent ports, and internal structures for housing and mounting the electrical and optical components. Details.
  • Electronics -- A very low power draw (2 micro-Amp average) LED blinker circuit connected to... Details.
  • Power -- a photocell array that gathers ambient light energy and stores exess in a large (10V, 1F) ultracapacitor for dark operation Details.
  • Treasure -- A magnification system with a fractional millimeter font text image and circuit schematic describing the artifact and its provenance. Details.

Below are some pictures of the artifact and its components. Click on any of the images for a larger view.

The assembled aluminum-bronze encased artifact. Visible are the solar panel window with protective glass covering, circular side openings to illuminate the contained image, and the magnifier viewport on the end.

The individual components that were assembled to make the artifact. The circuit board and the LED holder subassemblies have already been put together.

The partially assembled artifact with bottom panel removed. Note the aluminum structure holding the loupe magnifier and printed image. The circuit board and the ultracapacitor are also shown. The LED and the solar panels are already installed.

Detail of the soldered circuit board.

Another stage in the assembly. The circuit board has been installed and partially embedded in paraffin wax. The next step is to make solder connections between the board and the LED, solar cells, and Ultracapacitor.

The micro-printed "Information Treasure" placed beneath the magnifier. The yellow glass protects the printing from the fading effects of blue and ultraviolet light.

Components of the optical assembly for viewing the micro-printed image.