Thomas Edison is perhaps one of the most famous inventors in the world, ever. One of his marque inventions, the phonograph, came from side note discoveries as he was working on projects both to improve the telegraph (at the time a mature technology) and the telephone (at the time an infant technology not yet mass produced).
It was through Edison's quest to produce a verbal telegraph (a telephone concept) that he and his research group had been testing and working with numerous materials that would transfer the vibrations of the human voice. In an almost playful exercise, they felt vibrations on a stretched material and thought to put a needle on the back of it and have it scratch on coated paper. They reversed the rotation of the paper and crudely they heard the voice recorded and played back. This discovery went without much priority for almost a year before competitive efforts in Europe pushed Edison and his team to create the first phonograph using metal needles and metal foil.
They "cobbled" together this product out of research on carbon needles, metal foils, scratch recording and mechanical rotators all from R&D in other efforts. The first invention to make Edison famous was an accidental product of other pursuits and a repurposing of research, thoughts and creative drive for other products.
The electric light bulb came much later in his fame.
We know that tinkering is often encouraged with software and Internet companies but often discouraged with
manufacturing companies. We need to get back to the roots of invention. For all you would be inventors - tinker away. Remember Edison, one of the most famous inventors in history, had neither a formal education and no formal technical training. He had passion, drive, commitment and a whole lot of smarts.