How To Make A Crystal Radio – No Batteries (Updated Version Available)

This is a DIY crystal radio they were very popular in the nineteen
twenties they require no external power to operate no batteries no power nothing they operate strictly on the radio waves
that are coming in so if you’re looking for an emergency radio where when the power’s out, or you don’t
have batteries or whatever this is the thing to have this is made primarily from scraps, in fact you can get almost all these pieces by pulling other stuff apart and there’s only 3 major components There’s this coil, which you make yourself,
there’s this crystal diode which is kind of the miracle that makes this work and it comes Radio Shack it is very cheap and another little resistor which you can pull out of something else or buy it from an electronic store for almost nothing. There’s a piece of plastic tube or you can also use a hard cardboard tube some wire you can get out of an old
transformer. I happened to buy this Spring clips, you don’t really need the
spring clips, a lot of people use the brass screws and washers to hold the wire down. Give you some connection points. There’s this, which is the tuner. It is nothing more than a stainless steel big size bicycle spoke that’s been shaped
into what is needed There’s a wood bead on top to hold on to Going over this way again, the diode again
and the resistor and then it goes back to the coil and as you can see that’s it. There’s no other component It’s great for those times when you
need a radio, you don’t have batteries You don’t have power and also they’re fun to play. Let me show you how to build it. It’s a weekend project, very simple so let’s get started 2 of the main pieces. A piece of wood. Which is… 21 by 17.5 cms If I remember right. I’m using a 2.25 inch, specs call for 2.5 inch, but 2.25 should work. 2.25 will work. It’s thin wall PVC. 7 inches long or 17.5 centimeters The piece of tubing we looked at earlier. And what I am going to do is wind this with wire and we just need enameled wire and you can get it, from for example, an old transformer. You use the heavier windings not the lighter ones. This is from an old ballast From a fluorescent light I unwound the ballast. What I am going to use is it’s a heavy enameled wire I bought, I think I got from Radio Shack or someplace like that. On to the next step. I’m going to show you how to wind this coil using a small one. because the big on is too hard to keep on camera, it keeps going out of frame It works the same as for a big coil. I just cut off a small piece. You need a hole on each end of tube and then you’re going to start your wire in 1 hole and you are going to wrap it nicely until you reach the other hole and it will go through there and then you will bend it over sharply to hold it, you can put tape to help hold it. Let’s get to the wire One of the tricks:your wire needs to be smooth and unkinked See this first part? It’s not smooth. So we will put that inside the tube. You want to make sure your wire is smooth and unkinked Notice I’m using the toilet tissue holder to hold the wire? You do not want the wire to come off the ends all squiggly and spirally. You don’t want the wire to kink. This is the most difficult part it’s not really that hard, but it does take 2 hands which is the reason I am using this. You want to get yourself a pretty good length of wire in here. 6 inches or so Bend over sharply in there, like that and then you want to start wrapping it nicely. It doesn’t matter which way you go The first turn is very important because it is how every thing else is going to fall If it is crooked all the others will be crooked. You want it tight and straight You see that gap? That gap is no good. Push them together push together 1 trick that helps hold it together You can put a little bit of white glue on it. I won’t do it for this demo because it’s a bit messy. It will make things hard to see Put a bit of white glue on here, spread
out you go along, it’ll help this stick to the coil. You not want any kinks. 1 problem with glue you’ll get you get little balls of glue underneath the wire and then it will not lay out nicely Keep the wire tight. You want these coils very tight And that was not beautiful I am pushing the wire this way and I’m turning at the same time. This is why you need both hands. To keep it tight. Glue helps You may ask, “would this short coil work for a radio?” and the answer is yes it would. it would not pick up very much. It would
have a very limited range of frequencies The longer the coil the greater the
range of frequencies but also it is harder to tune because your tuner
rod has to get longer and longer to sweep across here, I will show you that later I will continue off camera and Then I will show how we finish it out. here we are getting toward the end This wire does have a few kinks that I am pushing out as I work it on here. Here’s our hole. 4 or 5 more turns should do it. Keeping it tight. There’s a kink. Absolutely make sure there are no kinks. Beauty counts in this. Don’t let go of it because it will come springing off of here. Then you get to start over. okay we’ll call it good here okay here’s the last hole hold this tightly Give yourself plenty of spare. Cut it off In that second hole we drilled right here We’re going to tuck this wire down inside there. Again, we don’t want to kink it. Got a little bit off. Again the glue would help hold it. Pull it tight but don’t break it OK and I’m going to bend it sharply inside here so it won’t come loose Again tape or glue will help There’s the coil, not too bad Your coil will be 6-7 inches long The coil I made had too many windings, 170 windings which is ridiculous. 80 to 120 is pretty typical That’s how you do it. And what you will do is mount that. I will show you that with the other coil This is hardest part so if you can this, the rest of the radio is simple There is 1 end of it The other end. It is close wound. And I used glue. I have to clean the glue off and then spray it with clear acrylic and then the coil will be done Most of these radio there’s a screw from here to the bottom base piece and they will put a few washers in here to space it because you do not want the coil to touch the base. I made this little block and as you can see it’s crude but I sawed into the block roughly the shape of this tube. Chiseled it out and then used a rasp. and it’s fastened on the bottom with a couple of screws. And fastened right here with 1 screw And the same on the other side Spring clips. and mount a couple over here for the resistor and earphone and couple here for the diode And a couple here for the antenna and ground. And we still need to find our wiper which goes from here to here. you can see on this end all we’ve done is run the wire out of here and soldered it on the clip.You don’t have to solder it and that will here, so we’ll put a screw there. You can see I just looped the wire around here and soldered it. Soldering is best you don’t have to do it
but if you can it helps a little bit Note the the enamel has been scraped off
the wire that one of the trickiest parts. You got to get that brown coating here off of there until you have a shiny copper color like that You can see a little bit right there near my
finger you get the enamel off of there, solder it. if you’re going to use a brass washer
instead of these clips, that’s OK too, just loop
the wire around the brass washer and solder it on there and you cannot use stainless if you are going to solder, stainless and solder don’t work together so I recommend brass for that reason but you do the same thing put the wire
loop around here Solder it on there and when you put the screw in there and tighten it’ll make good contact Brass clip and stainless screw And on this side, a brass clip. Let’s talk
about these 2 clips right here the for your earphone How far apart should they be? The answer is a little bit farther apart than your resistor This is a 10K ohm resistor It needs to go in there and be clipped if you’re using washers and screws, the distance is enough so you can wrap leads around so if you’re using screws and washers
you may want to bring the little bit closer to the open space to wrap wrap the leads around there and the same with the diode exactly the same issue with the diode a
make sure you have enough distance there that you can connect it. If you are using spring clips you want to be a little bit longer I’ll you want the wires a little bit outside the clips and if you’re using screws and washers you want to bring them a little bit closer so you can wrap the wire around the screw and washer setup to hold it firmly. you don’t have to you those spring clips I’ve been showing you another technique a lot of people use is just a screw and brass washers and what you’ll do is run the wire that you want to connect around, wrap it around the screw between the 2 washers and when you tighten it down it will pinch it, clamp it in there. It’s a little less convenient than the clips but it does work very well It is the original method of making connections In between the wiring that goes from here to the wiper and then over to the first
clip on the diode which would be here. This is the only tricky part of the wiring. It will look like this and I got brass wsher and a piece of wire that’s going to go from here to there. And it’s going to be screwed down right here. for the wiper. It’s going to look like that and the wiper’s going to go on here like that What I did to make this, I took a piece of copper wire and you can
see it’s relatively simple I made a loop on each end and soldered it. Again soldering is not required. I prefer solder I soldered it to this brass washer and then again I made a loop over here. I
trying different types of loops to see which worked best and that’ll be the connection from here here and to the wiper. Let me talk briefly about the wiper This is what you use to select the station In this case it’s just a piece of stainless steel, a heavy duty bicycle spoke I heated it up and put a loop in this end of it. Put the screw through it to hold it down. Right here in this hole and when the screw is in place it will push down here and apply some pressure and then that is used for selecting the station. On the other end I bent the wire up and put a knob on it. The know is for your fingers, if you touch the metal while you are tuning it changes the tuning. So that’s the wiper. I’ve got this loosely in place. and when we go to put on the wiper you need a washer down here which is the one contacting this wire then you need another washer on top of the screw so that when you turn this it moves nicely between the washers Without the washers it will jam and try to unscrew the screw. So we are going to put this here like this. Put this in here and then screw it in board and you that to set the tension on the on the wiper up here And that’s how the wiper is installed. This is pretty much it. We got the wire coming out of this side of the coil. Comes down here It’s soldered on to this clip. The resistor
will go across here and then the earphone will be connected to here These 2 clips are screwed together. If you’re using washers you just have a screw and a few washers to make the connections Diode will go
here then there’s the wire here to wiper as we showed earlier wire goes over here to this contact which will be the ground. We will connect the ground wire here back here the antenna wire, this clip will go to our antenna and then of course we showed earlier
goes into the coil so that’s pretty much it. That’s the assembled piece. I will show you some finishing touches. We need to remove the enamel off this wire so the wiper can touch it. If the radio’s not going to work it’s probably because the enamel has not
been removed from here or from one of these 2 end pieces. That’s the most common error. Getting the enamel off there can be tricky. I’ll show you how in a second. Then we’ll finishing assembling and to test it To remove the enamel, you have to get the enamel off of here because you need a good electrical contact to the coil to get the enamel off of here; you want a stripe across here where the enamel is gone. I start out with a piece of sandpaper and put it around the wiper like this. like this What will happen is it will mark you can see it scratching the copper copper wire and when you’ve got a good mark on where it is going to touch taker your sandpaper and stand up and down this direction You can see it shining up nicely. Work on that until you’ve got a nice clean copper strip across here then take a brush, toothbrush rag or
something like that, piece of tissue and get the copper and enamel dust out of there. If you don’t get the copper dust it will short between the coil windings and you won’t get a very good very good separation, clean it out with a brush When it comes to these connections here, to scrape the the enamel off the copper I use combination of a sharp knife like this and sand paper. A lot of people will burn it off, I don’t like to do that it softens the copper Just use a sharp knife. Get all the enamel off all the way around the wire make sure it is shiny all the way around
the wire before you make your connection Almost forgot to mention the important parts. Put your diode here. It doesn’t matter which way it goes Usually you have to worry about which way it goes, but not here Your resistor here, it has no direction either and then the last thing is to clip in your earphone Again it does not matter which way the wires go. One wire on one side, one on the other I put an extender on my earphone which is why the wires are different colors Ready to use! This is it in use Got an earphone over here on this side. Here we have a ground Ground from here to the air conditioner The antenna. It’s hard to see the wire. It goes up here like this Goes to this insulator. Then all the way
out there to that other fence where it’s connected by a string to keep it from touching the metal Be careful not to run it near electrical lines. Notice we have no electrical wires out there You never want to run it across electrical wires or anywhere near electrical wires and make sure your ground has nothing to
do with electricity make sure it’s going to a water pipe or similar. For operation that’s pretty much it. Just listen and tune. So does it really work? Well, you have a listen.

100 Replies to “How To Make A Crystal Radio – No Batteries (Updated Version Available)”

  1. tsbrownie Is that brass thing really imporant? or I can use similar of it. I m doing your video right now so please, answer. Thx

  2. Hello my name is Tom Murphy i am 61 years old and know very little of volts or amps ie Imust say i really enjoy how you break the build down very good ! one thing i have a question on is resistor i got some that amazon said who work my question is this how what does a resistor due and i notice you can get a station with out them how can i tell if they are working , my next question how to drop var cap into a radio love your info god bless tom

  3. Nice build. I made one of tgese with my grandfather in the 80s, he made one as a child in the mid 30s. It was a great memory for both of us. Ultimately, building this simple am crystal set with him sparked a lifelong interest in electronics. I went to school for electronics engineering, but ended up only working in the field for a few years. Still love to see people build cool things and watch the amazment of children at mnaking suchva seemingly complicated thing with so few parts. Everyone should build one, just for the experience.

  4. Well Done. I think i will give it a try. I may just try to purchase one all ready made , the coil may be the problem for my 75 year old hands.

  5. Have you made another with a tickler coil? The result is way too short to guess the song and win a prize. Really good volume out of it but…how many other stations can you select or are sum crammed together? If you only got one station, have you tried bridging the diode with a capacitor? I could see action on my oscope even when the radio hit dead spots but with a 201 pf ceramic across the diode, many more silent stations were audible. Maybe its a good thing but i do not like accordions in Mexican music. God, i HATE accordions!!!

  6. The first crystal radio kit I got was a X Mass gift from my dad in 1962 and when we / he assembled for me I was astounded that it worked without batteries!  Even in 1962 every kid knew that cool toys and radios needed batteries to work so this gizmo was too super cool!   Later from time the Walgreens Drug store would sell near the check out the Rocker Radio ! for your listing  pleasure or about $3.95 in 1965 money.  .  I bought a couple but my peers though it just make look like a nerd when I was using it so I gave up on them and they ended up lost or broken .  Still love the idea of this very old tech.

  7. Uma vez eu vi uma reportagem que citava sobre um radio que usava uma lamina de babear e uma agulha substituindo o diodo.

  8. Shouldn't the output be between the antenna and the ground?
    Antenna to where ground and ground to coil before the resistor, plus capacitor between antenna to ground, left side of the coil free.

  9. I knew a guy who built a radio powered crystal set. He used the rectified dc power from a strong station (WMAL) to power a germanium transistor and a 12" speaker. Very clever invention.

  10. I used to use Oatmeal boxes and gallium crystals with a "cat's whisker" to choose the best "spot" on it fot the loudest volume. I have NO IDEA where to get the Gallium anymore. This is going back to the mid 1950's. You will probably have to use a germaniun rectifier diode (1N34a type) instead of the usual silicon diode (1N914 ot 1N400X types) because of the lower forward voltage drop. If you cant find one, I suggest a eBay schottky diode as it has a much lower forward voltage drop than a silicon diode that's likely available through hobby outlets. To "unkink" and relieve some of the wire "spring", anchor one end on something like a doorknob, run out 10' or 20' or so then literally stretch it a fuzz, maybe 1/4" or so, then lay it flat. You should mention that it only works for a close proxmity AM radio stations (usually only one. The tuning isn't very selective) and a high impedance earphone. The resistor may not be necessary and may reduce the volume further which is undesirable. It depends on the type of earpiece used. If it's a crystal earpiece, it may be needed. A GOOD antenna is essential. Perhaps 50' of wire strung up outside with insulators on both ends, the longer the better, and a good earth ground (rod pounded into damp dirt) is equally important. What you are doing here is creating a resonance with the transmitter and "stealing" some of it's power ala Tesla's theory. Great fun for damn sure.

  11. You don't even need a diode, I've used rusty bolts or screws in the past (anything that will act as a semi conductor)

  12. It might make it easier to wind the coil if you put a piece of double face Scotch tape down the length of the form, maybe even two on opposite sides of the tubing. Also, a spot of hot glue to secure the ends to the form when you are done. I built my first one about 65 years ago as a Cub Scout.

  13. it does need a GERMANIUM diode ( yes you did specify it in your parts list) but its really important a silicon diode has a 0.7v drop while germanium is only 0.3v so more sensitive.

  14. When I was 12 I made one using a 1N34A diode ,a 400 microfarad capacitor. The coil was a 5 inch 2×2 wood block with the corners rounded off in a lathe. I used the lathe to wind the wire on the wood . sprayed shellac on it to keep the wire coil together Mounted the coil with 90 ° metal corner brackets at each end so that one corner of the coil was on top. the wiper was a piece of galvanized metal strip with a copper wire solder along the length of it . mounted on a block of wood level with the top of the coil.
    the most important part was the antenna..I used 200 feet of wire strung between the house and a power pole on the other side of the neighbor's yard.
    the antenna will be more directional in the opposite the end picking up stations that way.
    if it goes east to west and if end is west of your radio stations east of you will be stronger.

  15. multi-task, you can wind your coil while sitting on the pot doing your business. Just make sure you keep the toilet paper close by.

  16. I remember building one back in 60s only instead of a crystal we used a razor blade and peice of graphite pencil lead

  17. Wonderful instructions my dad made radio receivers for fun my kids not too so. What a great simple receiver. Thanks

  18. Not quite;
    50 to 100 feet of antenna wire. Very solid connection to Earth GROUND.
    And of course, a quality set of high impedance Crystal ear phones!
    The you can listen!

  19. there used to be great places around the country called radio shack where you could buy kits to make these .. but when we stopped educating out children we stopped needing easily accessible scientific objects.

  20. Great video, very informative, thanks. FYI, POWs used to make these to hear 'the truth' about the war. It gave morale a huge boost!

  21. I had one of these in the 1950's when I was a kid. My bed was next to a window, and I ran a wire outside the window and wrapped it around a screwdriver I stuck in the ground. I used the window screen for an antenna. I would then lay in bed and listen to The Fleetwoods and The Coasters. With the ear plug my parents thought I was asleep. There is nothing like listing to "Dream Walk" by Santo and Johnny at 1:00am on a summer's night.

  22. Made one when I was 10, from a kit. Wound the wire, etc. Had a small antenna wire, could pick up local stations. Outside my bedroom window was a sycamore tree, about 30 feet tall. Ran an antenna wire about 20 feet up the tree. I could pick up Mexican radio stations at night. Pretty cool stuff.

  23. I built a crystal radio with my dad when I was about 8. He had one in the army and he strung the antenna on the clothes line outside the barracks so the sergeant would not notice it. My antenna stretched out my window and across the back yard. It was a circuit with a variable capacitor for tuning and I loved to tune it to different stations and hear music and talking from all over. We were near enough to Canada to get French stations which to me sounded so foreign and mysterious! To this day, I fall asleep with one ear bud in my ear listening to Podcasts.

    Brownie – a trick I learned once was that you could make a diode using a safety pin and a quarter. You screw the clasp of the pin to the board so that the elbow sticks up in the air and the point comes back down onto the center of the quarter, held there by the spring of the pin. The surface effect makes it somewhat of a diode at higher frequencies. You can hook the wires by twisting one onto the pin clasp and the other underneath the quarter. You might try this on your kit there. Someone below mentioned a similar trick with a razor blade and a pencil lead.

    Thanks for the cool video and the wonderful memories!

  24. to many complaints that it doesn't work. Morons! it does at 20:51 to 20:54 you didn't bother to wait till the end. no patience. i made one in 7th grade 1975. Thumbs up. i Like, OLE!

  25. Can this be tuned to the area of 24-30 MHz? If it can how does one figure out how to build for this range? Thank you.

  26. Unfortunately, Radio Shack does not carry electronic components anymore. They're basically an overpriced Circuit City now.

  27. 3 things will cause your crystal radio to NOT WORK. 1. You must have a long wire for an antenna. 2. You must connect the ground to a good metal water pipe or other metal going into the ground. 3. you must use a PIEZO or CRYSTAL earphone…. not one of those modern magnetic wire earphones. Also be sure to scratch off the enamel paint on your copper wires AS HE explains in his video. I made one of these in the 5th grade back in about 1965

  28. The time has come for those who has knowledge, wisdom and information about how to do. they will go far away with respect to those whose every day passing same. thanks for sharing this info about how to make a free radio (; I am a new subscriber now

  29. Radio probably wouldn't work at all if the Sky's charge was not "+", and the Earth's " -". There is where the real power lays, like a battery requiring only a wire between to discharge the circuit.

  30. yes you can solder stainless, but you have to use hydrocloric or maybe muratic acid instead of flux. used to solder type 304 stainless all the time in sheet metal shop using 50/50 solder.

  31. I enjoyed watching this. I remember from movies and books that POW's built radios so they could keep track of what was happening. Does anyone know how they did it?

  32. Try double sided tape along the PVC before you start the winding. It won't be too sticky, but it will help hold the wire into place. Thank you for such and interesting and informative video! Most people don't know about this kind of thing.

  33. Crystal radio kits used to be a big thing when I was a kid – lots of kids in the 1960s used to build them – you found them (along with lots of other science-stuff) in ordinary toy stores and our parents would give them to us for christmas or birthdays. Some of them did not use a manufactured solid state diode, but a "cat whisker" diode made with a piece of crystalline galena (lead ore) and a safety pin. And yes, my antenna was long – running from a window to a tree in my backyard at least 80 feet (25 meters) away. The ground was a heat dict register screw.

    No wonder so many young people are so STEM-illiterate today.

  34. God bless tsbrownie for being so patient in answering the same questions over and over. This is ancient technology(over 100 years old) that obviously works. Follow the instructions and it will work. No it won't pick up FM or short wave etc. If you have an antenna, a ground, a coil, a diode and headphones it will work. It's like a miracle you have built with your own hands. Try to appreciate that miracle. No it won't blow you away with fidelity and volume. It is what it is. A good antenna and a good ground are important. In a darkened room you can strike the antenna and ground wire together and see a spark….or put both wires on your tongue and feel the electricity you are capturing from the air. Follow the instruction in the video. In fact, I have made some down and dirty(quick and ugly) versions that also work. Forget the overkill about spring clips and screws and washers…just strip some insulation from the ends of the wires and twist the wire ends together to make a connection. I'm not advocating sloppy craftsmanship…just saying…if you get the connections made, it will work. Appreciate it for what it is.

  35. Mid to late '50's KIX cereal had them for I think two box tops & $.50 and they sent you in the mail. I remember it came with an alligator clip which all you had to do was ground it like the center screw of an outlet cover or the finger stop on rotary phones. The good ole daze!!!!! It was 2" long and like 3/4" square. Came with an ear piece.

  36. We used to build these when i was about 7 years old and now maybe with this video todays generation can experience the same magic that I had as a child.

  37. i read the comments below about why you can't include am broadcasts. what is the coolest station or broadcast you have heard with the radio? can you stick your fingers in the tube to get better reception? btw– thank you so much for this instructional video. good karma points.

  38. just built one exactly like yours hooked everything up right connected the ear phone and nothing!! do you have a email so I can show you a picture of it ????

  39. great educational and informational video! wish you had started with a little demo of how it sounds in the beginning and then went on to show us how to make one! 🙂

  40. Yo J.o.A.g. Agradezco ,los vídeos de Electrónica estoy Aprendiendo y estoy
    Muy fortalecido de buenos
    Conocimientos, de Radio ..
    Gracias you tubo…

  41. TSBrowinie…I thought antennas needed their own ground, like an outdoor tv antenna. I know the set is grounded because it’s needed to make it function, but what about for real grounding purposes?

    Ie: when the set is brought inside, the antenna is left out there all alone without the set/ground, what happens when struck by lightning?

    If set is 24/7 hooked to antenna and always indoors, even if grounded, aren’t you inviting the strike to come inside the house and go thru our internal ground system? Thanks

  42. And this guy unknowingly proves what tesla had been telling us his whole life! Free energy exist all around you.

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