3D Printed Radio That Works!! Easy to Make





Introduction: 3D Printed Radio That Works!! Easy to Make

I'm thrilled to unveil my new 3D printed AM radio! I was inspired by the diy crystal and foxhole radios of the early 1900's, but I created my own design to be as simple as possible.

I put a lot of work into the video. It should explain everything so check it out and thanks for watching!

Step 1: Materials

Download link for 3D model: https://www.thingiverse.com/thing:2752141

1 Piezo Earphone

1 Coil of 24 AWG Magnet Wire (aka Enamel Wire)

1 1N34A germanium diode

1 small piece of aluminum foil

1 paper clip

1 package of Hildie & Jo 45 Cord Ends (5x10mm Springs)

These should be easy to find online. The springs I got are sold at Joann Fabrics. Search Silver Cord End Springs but any similar 5mm diameter springs should work.

Step 2: Overview

I think it is important to show you an overview of the circuit and how everything will hook together before we get started.

Step 3: The Coil

This is a very important part. Wind the wire tightly around the 3d printed coil holder and make sure there is no overlapping and that each layer is tightly pressed together. Take this part slowly and use tape to hold the ends and tape it if you need a break. See the video for reference.

Then we need some of the metal revealed on the front so use some sandpaper to gently remove some of the enamel. Too much sanding may cause the metal to short out. Wipe away any sandings when done.

Step 4: Assemble 3D Print

The coil holder will slide securely into the printed base. Feed the left side wire thought the small hole on the base and clip to the side. The right side will go into the right side spring but sand off the enamel first so it makes contact.

Step 5: Paperclip, Diode, and Earphone

Open the paperclip and flatten it. This will fit into the two sides of the base. It should be close to the coil without touching it. Cut and sand off the ends of a small piece of wire to connect the paperclip to the left side spring.

Attach the diode in between the left and center springs. Either direction will work.

Attach the piezo earphone to the center and right springs.

Step 6: Tuner

Cut and fold a small piece of foil and loop it through the paperclip and wire coil. It should touch both the paperclip and coil of wire. Fold it through the printed tuner.

Step 7: Setup

The antenna wire should be layed out flat about 15 to 20 feet or more and go into the left spring. The longer the better. Sand a few inches off the end of the ground wire and wrap it securely around the metal sink faucet. Connect the other end of the ground wire to the right side spring. Sand the enamel off this end too.

Step 8: How to Use

Slowly slide the tuner back and forth and you should hear faint static sound and eventually you will find a radio station!


Connect to an amplifier if the volume is too low.

Make sure everything is connected correctly, reference the video.

Metal objects and also your body can affect the radio so occasionally step back.

Make sure all connecting wires are sanded to expose the copper for best connections.

Play with the antenna. Try to tape it up higher, change the direction, or make it longer.

I hope you enjoyed this! Thank you and see you next time. :)

Step 9: Alternative

This is just an option. The diode can be replaced with a safety pin pressed into the lead of a pencil tip that makes a point contact on a razor blade that has been heated until it turns blue. This will allow current to only flow in one direction just like the diode. This is much harder to get working but it is possible.

I like to make 3D animations, 3D programming, and 3D printing on my channel so subscribe to see more! www.youtube.com/c/3dsage



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    77 Discussions

    I'll reiterate my post as a simpler question:

    Why are we not using this crystal-DC method for creating DC current in more devices? Seems we could replace the need for USB charging, but having a constant input of low DC-AC, or something like that. I'm knew to this world...

    Can a speaker be substituted for the ear piece so a group of people can hear it working, say a class?

    3 replies

    This would be a great class project. If one person wants to hear this, then the piezo earpiece is the only thing that would work. Now if you use an amplification device, then any speaker would work. I used my guitar amp in the video and that would be enough for a classroom to hear.

    Thank you for the response. Guess I should have waited till I got home from work and watched the video though.

    Have a STEM career day coming up, and this may be the kind of project that can capture imaginations. Thank you for sharing it.

    You could use a small battery pack to power a small (perhaps homemade, ie, miniature) amp.

    One thing to keep in mind is to be sure that your home has copper or iron pipes through out. Some modern homes use PEX tubing instead of copper plumbing. Since PEX is plastic, it won't work for grounding the radio (or going to earth). If you home has PEX tubing you could try wrapping the ground wire around the pipe where the water comesinto your home, that should be metal. The alternative is to buy a grounding rod and pound that into the ground. Then, attach your ground wire to it.

    4 replies

    That's exactly what I was thinking when I saw him connect to the faucet.

    However, I am surprised nobody has mentioned simply making a connection to the ground terminal of any wall-socket in their house... (Your house should already be grounded. There's no need for someone to install a ground rod, when there should already be one.) When I first constructed a simple foxhole -radio like this one, I used a wall-socket ground and it worked well.

    To do this safely, you can take any appliance's plug, wrap the magnet wire a few times around the base of the ground-prong (carefully making sure the magnet wire does not touch the hot-prong), and insert the plug into the socket.

    You could also connect the magnet wire to almost any metal enclosure/frame of any electrical appliance/device, since all metal enclosures must be grounded by design. So things like washing machine, computer case, etc. all would probably work fine.

    If all else fails, a sufficient counterpoise can easily be constructed. Here is some reading for anyone interested:


    This is great to know for any ungrounded devices that may appear in my vicinity... or that I may build...

    Good to keep in mind but I looked at my sink and I have plastic pipes but it still works. So I was trying to make sense of that. Maybe there is enough metal in the whole sink for the current to flow to. Or maybe the current can flow from the pressured water in the pipe down until it eventually reaches metal or the actual ground. Not sure but I think mine worked ok. An actual metal rod stuck in the ground might be an alternative for troubleshooting.

    It's not the metal, it's the connection to earth, either through the water or via electrical earth bonding of the metal sink.

    Yes a rod in the ground will work. needs to bee deep and into wet soil

    I just read about this. Very impressive. I do foresee a return to low-tech, but in combination with high-tech. I've been teaching myself electrical engineering and get excited when I find older gadgets, with less streamlined circuitry (ie, microchips). Is there any way to use the crystal to create higher DC voltage? It seems to me that we should be taking advantage of that old tech to create devices without batteries/ recharging, or at least to supplement the batteries with DC input.

    have you tried a bridge rectifier? it should increase the output by 200%

    1 reply

    Oh I didn't know about that. I would like to hear the comparison. Thanks for letting me know.


    5 months ago

    I've got a similar toy when I was young, the result was amazing.

    Didn't know that it was possible to replace the diode with a razor blade; I'll probably give it a try...

    1 reply

    That's great! It took me a lot longer with the razor blade but it is so amazing that it actually can work.


    I made so many crystal radios as a kid my mother was sure I'd never get out of the house. DXing (Late night station hunting on am) was my first real hobby. This makes a lot of old memories come to mind, and now I have to see if I can still make a radio. Want a real challenge, try making a crystal radio as small as possible that still pulls in stations from a hundred miles out at night. Thanks for posting such a creative idea.

    2 replies

    I'm glad to hear this brought back those great childhood memories! I would like to make a really small version and 3D printing would make that possible. Thank you for the nice comment.

    Looks cool. We used to make these as kids, when the 3D printer wasn't even a gleam in a sci-fi writer's eye!

    Most important thing is a long aerial and a good earth. Any germanium diode should work. The original "cat's Whisker" used a Galena crystal although a peice of coke was said to work