You will need
  • Aluminium pin, copper pin, transistor, water, salt, copper wire, aluminum foil.
Take an aluminium or iron pin and insert it into the tree, insert deeply to the pin went through the bark and through at an impressive distance penetrated into the barrel. Then, insert the copper pin into the ground approximately 30 inches. If not insert one pin into the tree, and then electricity will be more. The voltage between the pins will be approximately 1 volt.
Take a silicon or a germanium transistor and open it up, but will not damage the crystal inside the case. Connect the wires to any of the transitions, the emitter-base or collector-base. On a Sunny day, opening the transistor can replace the photocell, between the wires will appear the voltage 0.1 to 0.2 volts. Several transistors can assemble the battery, but collecting it, all the transistors need to choose one specific transition.
Take several glasses and fill them with salt solution. Next, take a few lengths of copper wire and wrap one end of each cut aluminum foil. Connect the beakers with a solution of wire segments to one glass, the wire was placed bare end and the other wrapped in foil. Voltage depends on the number of cups.