Saad Bhamla, an undergraduate in Mumbai, India, has invented a do-it-yourself hearing aid made from inexpensive, easy-to-find parts. “At bulk rates, Bhamla says, it would cost just under $1 to make,” reports Science Magazine. “But anyone with the freely available blueprints and a soldering iron can make their own for not much more — maybe $15 or $20, Bhamla says.” From…