Slingshot is a water purification device created by inventor Dean Kamen. Powered by a Stirling engine running on a combustible fuel source, it claims to be able to produce drinking water from almost any source by means of vapor compression distillation, requires no filters, and can operate using cow dung as fuel. The name of the machine is a reference to the slingshot used by David to defeat Goliath. Technical characteristics In his TEDMED 2010 presentation, Kamen announced several goals for and characteristics of the machine: five years of operation without overhaul or maintenance use less than a kilowatt of power (lower than the power consumption of a microwave oven) generate 1000 litres of pure water/day, enough for 100 people for hygiene and cooking meets the U.S. pharmacopoeic standard for water for injections requires no pre-treatment, pipelines, engineers, consumables (osmosis membranes, charcoal, etc.), or installation permits History Kamen came to develop the device on the basis of statistics that showed lack of access to clean water as a public health crisis. Statistics from the World Health Organization show that there are 900 million people worldwide without a readily available supply of drinking water and that some 3.5 million people die annually because of diseases resulting from the consumption of unsanitary water. Despite the fact that over two-thirds of the Earth's surface is covered with water, only 1% of it is potable. Kamen sought to develop a technology that would transform the 97% of water that is undrinkable into water that can be used and consumed on the spot, readily and inexpensively. The device takes contaminated water and runs it through a vapor compression distiller that produces clean water, producing 250 gallons daily (~946 litres), enough for 100 people. The test devices have been used with "anything that looks wet", including polluted river water, saline ocean water and raw sewage. In a demonstration at a technology conference in October 2004, Kamen ran his own urine through the machine and drank the clean water that came out. Kamen built two machines — a power generator that would output one kilowatt from "anything that burns", and the water distiller, which uses the electricity. In 2005, the power generator was tested for six months in a village in Bangladesh and generated enough electricity to light 70 energy-efficient light bulbs. The hand-made prototype cost each. By the end of 2005, a team of 200 at