Cheap DIY High Impedance Earphones

Crystal radios can feel magical, given their ability to tune in audio from distant stations with nothing but the energy from the radio signal itself. However, to achieve this feat, they typically rely on a high-impedance earphone to produce an audible sound with very little current. These earphones are hard …read more

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How Early Radio Receivers Worked

If you’ve ever built a crystal radio, there’s something magical about being able to pull voices and music from far away out of thin air. If you haven’t built one, maybe you should while there’s still something on the AM band. Of course, nowadays the equivalent might an SDR. But …read more

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Hackaday Podcast 070: Memory Bump, Strontium Rain, Sentient Solder Smoke, and Botting Browsers

Hackaday editors Elliot Williams and Mike Szczys bubble sort a sample set of amazing hacks from the past week. Who has even used the smart chip from an old credit card as a functional component in their own circuit? This guy. There’s something scientifically devious about the way solder smoke …read more

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Credit Card Chip Used To Make Crystal Radio

Perhaps the simplest radio one can build is the crystal radio. Using a diode as a detector, the design generally uses less than 10 components and no battery, getting its power to run from the radio signal itself. [Billy Cheung] decided to build a crystal radio using a rather unconventional …read more

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