Start with a Kit

• The folks at Sol Ideas have put together a kit that allows you to bypass one of the trickier steps but still lets you assemble the cell yourself. It's a small unit, about 4 inches per side, and so it's perfect for science fair projects or classroom demonstrations. The conductive material on most solar cells is titanium oxide, and the kit comes with glass precoated with the material. You'll need to get some fresh berries to crush to make your own dye to stain the conductive side and some graphite to rub the non-conductive side. When the cell is assembled, you can measure the output with a micro ammeter.
  
  

Go it Alone

• If you want every part of the process to be your own, you can buy a piece of copper flashing from the hardware store and combine it with some household materials to make your own electricity-generating solar cell. Heat the copper over an electric stove element to create the conductive layer, in this case, copper oxide. The heating creates a colorful layer of cuprous oxide topped with a dark layer of cupric oxide. After the copper cooks for about 30 minutes, turn off the stove and let the copper cool slowly. The black, cupric oxide will mostly flake off during the cooling as the copper shrinks faster than the black coating. Any remaining black that covers your brightly colored cuprous oxide beneath can be gently removed with sandpaper.
  
  Put the coated piece of copper and a new, uncoated sheet in a plastic bottle. Cut a 1 liter bottle in half so you have a large opening, like that of an open jar. Place both pieces of copper in the bottle, hook a micro ammeter to the copper pieces with alligator clip leads, positive to the coated piece and negative to the clean sheet. Add a little salt water to the bottle, head out in the sun and watch the meter jump to life with electricity.
  
  

Get Creative

• If you really want to go all Survivor Man, head to your local doughnut shop. Blake Farrow, a Canadian scientist, says all you need to make a simple cell is a doughnut, a couple of small pieces of glass, a pencil and some tea, plus a few incidentals. After you've finished your tea and doughnut breakfast, use the leftovers to coat a piece of glass, first with the powdered sugar, then with drops of tea. Tea stains the white sugar so that it can absorb light. Rub a pencil over a second piece of glass to make a counter electrode.
  
  Before you sandwich the two together, boost your conductivity with an electrolyte solution. Farrow drops iodine water purification tablets into a cup of grain alcohol and uses a dropper to wet the tea-stained and sugared glass. Hold the two electrodes together with some clips, and head out in the sun to see how you did. Attach leads from a standard voltmeter to the cell, and you should see an appreciable jump in current.