Ranking a site with widgets but no content

I'm building out some widget based sites that solve simple problems (think compound interest calculator, md5 hashing etc). These pages won't have much content on them. So I'm wondering how this will affect my ability to rank well.

My understanding is that Google is smart enough to understand based on time on site and other characteristics if your widget is relevant or not despite the lack of content to parse. Is there anything special I can do to optimize these pages for SEO?