{"id":43684,"date":"2020-06-03T07:29:46","date_gmt":"2020-06-03T11:29:46","guid":{"rendered":"https:\/\/swling.com\/blog\/?p=43684"},"modified":"2020-06-03T07:29:46","modified_gmt":"2020-06-03T11:29:46","slug":"credit-card-crystal-radio","status":"publish","type":"post","link":"https:\/\/swling.com\/blog\/2020\/06\/credit-card-crystal-radio\/","title":{"rendered":"Credit Card Crystal Radio"},"content":{"rendered":"

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Many thanks to SWLing Post<\/em> contributor, Paul Evans, who shares this article from Hackaday<\/a> that highlights a crystal radio built completely on a smart chip credit card by Billy Cheung.<\/p>\n

Hackaday<\/a> notes:<\/p>\n

This is possible because the smart chip on many credit cards contains a diode. It\u2019s then a simple matter of hooking up the right pads on the credit card to the rest of a crystal radio circuit, and you\u2019re all set. Of course, [Billy] goes the whole hog, building the entire radio on a single credit card. Other cards are cut up to create bobbins for winding coils to form a variable inductor, used to tune the radio. Doing this allows for a much cleaner, thinner design, rather than using a variable capacitor which is comparatively hard to find. Turning the dial allows stations to be tuned in, and with a high impedance earbud hooked up, you\u2019re listening to AM radio. Oh, and don\u2019t forget an antenna!<\/p><\/blockquote>\n

Cheung documented the whole process and even shares templates via links in the description of his YouTube video<\/a>.<\/p>\n