About 20 million people in developing countries need wheelchairs, but only 1% have them. And that's just the beginning of the problem: Even if those in need had wheelchairs, the probably would work on the rutted and rocky roads that they live with.
So Amos Winter, a PhD student in mechanical engineering at MIT, designed a solution. His Leveraged Freedom Chair is small enough to be used indoors, but it's also kitted with a pair of levers that allows the user to apply extra force to the wheels, and off-road like an ATV. "It is strong and stable in African terrain, and you can travel long distances and uphill without using too much energy," says one of the users, Abdullah Munish, a Tanzanian spinal injury survivor. "I would say that we have [a] life saver ... I just call it my little angel machine."
To adjust to rougher terrain, all a user has to do is move her hands along the length o the levers—thus creating more force and torque at the wheels. The wheelchair can move across almost any surface, even sand. And when they aren't needed indoors, they can simply be removed.
Perhaps more importantly, the wheelchair isn't hard to make, requiring only cheap, off-the-shelve parts, such as bike gears.
Winter has been refining the design, in real-world tests conducted in East Africa, funded by a $50,000 grant from the Inter-American Development Bank (IADB). After making the chair even more compact and light, he'll begin training local manufacturers to mass produce the design. With a few tools, each one should be able to produce as many as 1,000 units a month.