This filter lets you take pictures of the sun with any smartphone. Couldn't find solar glasses? Just print this thing so that you can still watch the eclipse.

Printing instructions and hardware links:
https://docs.google.com/document/d/1xRNrDGiOnvNecDEPBr6inkmVVydfFzhNrlUu_bi1Dag/edit?usp=sharing

Sorry for separating the links into a google doc, but Thingiverse tampers with some links causing them to not work correctly.