Instead of buying an eco-calculator water powered and run your old, slow to decompose in a landfill, you could make your own. It seems a lot to be green, convert your items to more environmentally friendly at something, instead of replacing the gadgets you already own. Thank you to a tutorial, you can easily your own earth-friendly calculators.

The tools you will need a calculator, carbon or copper rod son, a piece of 1 by 1 inch aluminum foil, a small cylindrical container, the son of two 3-inch, multi-purpose pliers include a glue gun. The materials are quite simple, nothing that you can not get from your local hardware store. I think it works like any other machines powered by water. You just need to be sure to fill the battery with water if necessary.