Read more: The Craziest Military Machines Invented By The Third Reich With the adoption of SOS, the world moved on, but for ...

you probably remember ads for “The Instructograph,” a mechanical device for learning Morse code. [Our Own Devices] has an ancient specimen of the machine and shows us how it works in the video ...

In short, it’s a life-saving device that emits an S.O.S. signal in Morse code over both the AM and FM bands. The device uses five 555 timers to get the job done, each of them dedicated to a ...