The AM broadcast band doesn’t have a lot of mainstream programming on it across much of the United States today. That’s a shame because a lot of kids got their first taste of radio and electronics by building simple crystal radios. [Eric Wrobbel] has a well-done page discussing some of the crystal radio kits and toys that have been around.
[Eric] should know, as he’s written two books on toy crystal radios. The pictures range from a 1945-era “Easy Built Radio Kit” which looks like a piece of masonite with a coil, some Fahnestock clips, and a cat whisker, to a very slick looking Tinymite from 1949. Honestly, though, the one we really want is the X-50 Space Helmet Radio that comes in a box marked “For Young Moon Travelers.”
Continuing the space theme, there’s a picture of a radio built in a rocket by a Japanese company. Oddly enough, there was also a crystal radio made inside a pincushion that included a thimble and a tape measure. Presumably, you could listen to tunes while you mended a sock.
It makes us a little sad to think of the times we built crystal radios and strained to hear pop music, sports, or news. With all the options today, it hard to imagine a young person listening to a tinny earphone to some weak mono audio. On the other hand, there’s still something magic about building something simple that takes no power and can pull audio out of the air around us from relatively far away.
We wonder what counts as today’s crystal radio? Is a blinking LED on an Arduino? An IC-based FM radio receiver? A simple robot kit? Perhaps if we were making a crystal radio kit today, we’d pair it with a preassembled AM transmitter that could take a feed from a phone or other audio device. If you want to be super modern, why not 3D print the chassis?