Reading Scientific American this morning I spied the innovation that won their annual World Changing Ideas Video Contest: the Leveraged Freedom Chair designed by MIT Mobility Lab.
It's a three-wheeled human-powered wheelchair that goes faster than normal and also navigates difficult terrain—rutted roads, cobblestones, trash-strewn slums. The genius resides in the vertical hand levers: Users simply grab higher or lower depending on how much torque or speed they need. It's like being able to change gears.
The drivetrain consists of common bicycle parts and so is "manufacturable and repairable anywhere in the developing world," according to MIT. Sometimes low-tech solutions are the most appropriate.