Bobby Lindsey (left), of Louisville, Ky., and Wesley Bornor, of Plymouth, Mich., work on their idea for a sensor for a refrigerator that measures volume of liquids and report those levels to a smart phone on Friday, April 10, 2015. Around 300 makers, engineers, designers and techies participated in a free 24-hour Hackathon at GE’s FirstBuild microfactory in Louisville, Ky., on April 10 through April 11. A total of $60,000 in cash prizes and hardware were available to winners. FirstBuild is a physical and online microfactory that uses small batch production to manufacture new appliances at a much faster speed and with less risk. FirstBuild leverages the maker movement, a largely growing co-creation ideology that allows ideas for new appliances to come from anyone, anywhere, anytime.