Kamen has worked a lot on a project involving Stirling engine designs. It tries to create two machines: one that would generate power, and the Slingshot that would be a water purification system. He hopes the project will help improve living standards in developing countries. Kamen has a patent on his water purifier, and other patents pending. In 2014, the film "SlingShot" was released, which showed Kamen's quest to use his machine to fix the world's water crisis.