Print and assemble this fascinating scientific instrument that you can use to detect the presence and magnitude of an electric charge. In addition to your printed parts, all you need is a glass jar, some aluminum foil and some glue. The only tools you need are a sharp knife and a straigt edge (although a file or sandpaper might come in handy).
Check out construction details with this YouTube video  then visit http://PrintableScience.com for an ongoing forum and complete information.