Friends and family are mourning the death of an Oakland product designer who collapsed and died while riding an electric skateboard in San Francisco, three weeks before the expected birth of his first child. Schnakenberg, a Pittsburgh native, was co-founder and design director at Sollega, Inc., where he helped design the solar equipment that the company manufactures, said chief executive Elie Rothschild. Schnakenberg also founded an Oakland consultancy, Infinite Collective, where he designed several products, including an electric skateboard and bike.