The humble clock radio hit the scene shortly after the war, but as we can see from this self-explanatory drawing in the November 1940 issue of Popular Mechanics, one John L. Story of Washington, D.C., had come up with the idea. He mounted a small toggle switch on the back of a wind-up alarm clock not unlike the one shown at left, still available on Amazon.

When this type of clock rings, the key for winding the clock unwinds.  The switch is carefully placed so that the unwinding key trips it, turning on the radio or other small appliance.  For students interested in the history of technology, this would be an interesting science fair project to duplicate Story’s invention and answer the question, “what is the simplest clock radio?”