The SolarAid solar-powered hearing aid has two things going for it: it is solar-powered and at under $100 it is incredibly cheap. That amount might stretch the resources of people in Botswana where it was originally created by Godisa Technologies, but it is a lot less than conventional battery-powered alternatives. The other benefit of a solar-powered hearing aid is that it can be used where hearing aid batteries are not readily accessible; environmentally-friendly with a humanitarian edge. The solar batteries need to be recharged every four to six days. [via Ubergizmo]