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How to Make a Crystal Radio – No Batteries, No External Power (2015) [video]
- MrXOR 8y agoFor Crystal Radio Lover: Foxhole radio (https://en.wikipedia.org/wiki/Foxhole_radio https://en.wikipedia.org/wiki/Foxhole_radio) How to Make a Foxhole Radio: https://www.youtube.com/watch?v=skKmwT0EccE https://www.youtube.com/watch?v=skKmwT0EccE
- brightball 8y agoI’ve been wondering how to do that for years! Thanks!
- 13of40 8y agoI read about, but never tried, an even more primitive diode for this: Burn sulfur on the end of a fine copper wire, then touch it to a piece of lead. Seems like you could do something with iron pyrite, too, but I can't remember the details. I'm sure they came up with a ton of these in the early 20th century that never made it into mass production. Edit: https://books.google.com/books?id=S1QyAQAAMAAJ&pg=PA46&lpg=PA46&dq=copper+wire+sulfur+lead+rectifier&source=bl&ots=VTJNHvvCGm&sig=roNipTzMhsT-Fv3o5HrtNN_IFF8&hl=en&sa=X&ved=2ahUKEwjR6s7-hsnfAhWn64MKHePDDi4Q6AEwD3oECAQQAQ#v=onepage&q=copper%20wire%20sulfur%20lead%20rectifier&f=false https://books.google.com/books?id=S1QyAQAAMAAJ&pg=PA46&lpg=P... Unfortunately it seems like you need a power source to initially condition the rectifier, which you might not have in a WWII foxhole.
- tubetime 8y agoburning sulfur on a chunk of copper will also make you a memristor. interesting effect...
- deleted 8y ago[deleted]
- MrXOR 8y agoThanks. very interesting, I'm gonna to make a memristor! https://news.ycombinator.com/item?id=9853984 https://news.ycombinator.com/item?id=9853984
- airbreather 8y agoA plain copper oxide to copper Junction makes a serviceable diode for a crystal set. Interestingly this is the main thing to watch out for with speaker wires - not the cable, it is the junctions that matter by far.
- heyjudy 8y agoElectronics learning kits from the 60's-90's had this, maybe they still do. Crystal earpiece, adjustable ferrite coil or variable capacitor, piece of wire as an antenna and ground to metal drainpipe. No batteries needed as the power was taken from the station's broadcast.
- dhosek 8y agoI don't know if they have anything quite like those old Radio Shack 100-in-1 electronics kits any more. I've wanted to get something like that for my nephews and couldn't find it.
- dylan604 8y agoThey do: https://www.robotshop.com/en/elenco-mx-907-200-in-1-electronic-project-lab-kit.html?gclid=EAIaIQobChMIgdLYuJnJ3wIVi7bACh30wAXNEAQYAyABEgKiKPD_BwE https://www.robotshop.com/en/elenco-mx-907-200-in-1-electron...
- Hydraulix989 8y agoI really liked those kits. I didn't understand digital logic or analog circuits back then but tinkering and getting the satisfaction of building something is what eventually led to my career in engineering.
- trothamel 8y agoThe various snap circuits kits is probably the most popular modern replacement. https://www.elenco.com/brand/snap-circuits/ https://www.elenco.com/brand/snap-circuits/
- metaphor 8y agoTL;DW guy builds a passive AM diode receiver; hand-wound inductor. This is pretty much the first receiver topology that EE undergrads who take a first course in comm systems analyze in any detail. It's also a fun way to get a kid interested in electronics.
- anadem 8y agoYeah, I made and listened to a crystal radio as a kid in Britain. With a big antenna hung outside between trees I could listen in bed to Radio Luxemburg! (this was in the days when the BBC was the only broadcaster in Britain; Radio Luxemburg let me listen to the pop music the Beeb didn't play). And yes, later I went to an EE course at uni!
- 01100011 8y agoIt's also kinda fun to use them to sniff your various electronic devices. I remember holding one up to my old Amiga 500 and listening to the emissions it was producing.
- kabdib 8y agoMy home-brew Z-80 system, with dozens of unterminated copper traces wiggling rail-to-rail square waves at 5 volts in an unshielded cabinet, wiped out TV reception with herringbone patterns for a couple houses around. It was the 1970s, nobody knew it was me, practically nobody had computers at home or the knowledge of electronics to make the connection. Ironically I could turn it on today and no one would notice (unless it totally wiped out wifi, which seems unlikely).
- coupdejarnac 8y agoI saw this recently- a guy built an AM radio with a 555 timer. https://youtu.be/YC72J2VOSH0 https://youtu.be/YC72J2VOSH0
- MrXOR 8y agoIt is very simple to build a 555 radio. back in 2011-2012, Eric Schlaepfer had built it.
- coupdejarnac 8y ago...Yes, the guy in the video is Eric.
- smithmayowa 8y agoThis is very impressive
- grendelt 8y agohttp://www.neodux.com/read/Worlds_Simplest_Radio http://www.neodux.com/read/Worlds_Simplest_Radio
- JoeDaDude 8y agoFor the enthusiasts: https://www.midnightscience.net/home.html https://www.midnightscience.net/home.html