Appropriate technologies able to be easily and economically constructed from readily available materials by local craftspeople have a central role in the alleviation of poverty in the developing world. However, research and development of these technologies are generally apportioned relatively modest support by the developed world's institutions, in part because the operation of many of these appropriate technologies is dependent on relatively well-understood science accessible even to introductory college physics students. This paper describes a project-based assignment used to capitalize on this opportunity to motivate students to learn physics by offering them a chance to make concrete contributions to the optimization of appropriate technologies for sustainable development.