In order to make working headphones, we would need three key components a voice coil, diaphragm, and a permanent magnet. In this case the voice coil would be made out of a 28 AWG wire. The diaphragm is made out of small plastic cups, and the magnets are small neodymium magnets.
The voice coil is coiled wire that surrounds the permanent magnet. The purpose of a voice coil is to provide a path for the electrical current to flow through and it also generates a strong magnetic field. The voice coil acts a temporary magnet that attracts and repels the permanent magnet. The permanent magnet is just a magnet that provides a permanent magnetic field. The voice coil and the permanent magnet have different magnetic poles, North and South pole. The north and south poles push the diaphragm in and out. Also, the two poles provide alternating currents (also know as AC) that produce vibrations. The diaphragm amplifies vibrations caused by the voice coil and permanent magnet and pushes sound waves in different directions. Those vibrations then get amplified by the diaphragm which then creates sound waves. You need to have an alternating current (AC) because the AC’s vibrations get amplified by the diaphragm and it turns it into sound waves. Once the sound waves travel through the air they then hit your ears and there you have it, sound.

Step 1: Step 1: Material List

-28 AWG Wire (300 cm)
Can be bought at Home Depot or Lowe’s

-Small sheet of sandpaper Can be bought at Home Depot or Lowe’s

- Glue stick

- Ruler

-Hot Glue Gun

-Wire cutters or Scissors Can be bought at Home Depot or Lowe’s

-Roll of electrical tape Can be bought at Home Depot or Lowe’s

- 2 Bathroom plastic Cups Can be bought at any supermarket or Costco

- 8 Neodymium magnets with a radius of .5cm Can be bought online at Amazon

-Stereo Jack 3.5mm (aux plug) Can be bought online at Amazon

-Plastic Headband Can be bought at Target, CVS, or any place with hair products

-Felt Can be bought at any craft store

- Decorative Tape or Duct Tape Can be bought at any craft store

- Anything decorative that will bring your headphones to life (glitter, diamonds, spray paint, stickers, or etc.) Can be bought at any craft store

-*Opitional* Solder Tool Can be bought at Home Depot or Lowe’s

Step 2: Step 2: Assembly, Sanding, and Coiling

Now we have to create the voice coil for our headphones.

If you want to find the direction of current around you can use what is called the right hand rule. The right hand rule is a demonstration when trying to break down and understand an armature. An armature is a coil of wire also known as a voice coil. In the right hand rule, your thumb represents the current, your palm represents the force, and your fingers represent the direction of the magnetic field. When you use this rule your hand wraps around the armature. When this happens you rotate your hand as if you were wrapping around the armature. When this happens your fingers look as if they are going into the page which can be represented with a (x). As you keep on rotating, your fingers come around and look as if they are coming out of the page. This can be represented by a (.). Depending on the direction of the current which are left and right, there will be (x)’s or (.)’s on the outside of the armature while there are (x)’s or (.)’s on the inside. You want more coils so there can be more (.)’s or (x)’s on the inside so that way you strengthen the magnetic field.

Picture of the final voice coil

How to create a voice coil:

1. Taking your 28 AWG wire, measure roughly about 300 centimeters and cut it with your wire cutters or scissors. (You may end up having to cut some wire in the end)

2. Now get your glue stick and start coiling the wire 37 times around the glue stick to start creating the voice coil just like in the video below. We tested out the 37 coils of wire which gave the best sound quality and clarity. (Start coiling from the middle of the long piece of wire instead of from the end so you can have an even amount of wire on both ends) How to coil the voice coil: Coiling Video

3. Slide off the voice coil and cut both of the ends of the wire so they can be even.

4. Now begin sanding at least 5 centimeters of both ends of the wire till you see the copper under the red insulator. You need the copper wire to be visible because copper is a conductor of electricity and current will be able to flow from it. This step is very crucial because if the wire isn’t sanded completely then you won’t have any current flowing through the wire like you need it to do Example of how to sand the voice coil: Sanding Video 5. Now repeat steps 1-4 for the second voice coil

Step 3: Step 3: Magnet Positioning and Diaphram Assembly

Now you have your voice coil. Next key component to creating working headphones is to have your diaphragm and permanent magnet assembled.
How to secure the magnet and voice coil to the diaphragm:

1. Taking the plastic cup that we will be using for the diaphragm, place 2 neodymium magnets on the bottom of the cup. Out of all the cups we tested, the plastic cup worked the best to produce clear sound without being too low or muffled. The neodymium magnets are our permanent magnets and we need them create polarized magnetic fields between the permanent magnets and voice coil (temporary magnet). We chose to use 2 permanent magnets on each side of the cup (so 4 magnets per cup) because we found it made the sound much more clear than it originally was and gave a close to high sound. All the other number of magnets either gave lower or muffled sound.

2. Now take your voice coil and place it in the middle of the stacked neodymium magnets. The voice coil needs to in the middle of the permanent magnet because the magnet and voice coil attract and repel from one another. Which then creates vibrations that then push the diaphragm in and out and then creates sound waves. (It should look like the picture below)

3. Once the magnets and voice coil is in place, you can take 1 to 2 pieces of electrical tape and secure everything in place. (Make sure not to tape the ends on the wire) (Once everything is secured in place it should look like the picture below)

4. Now place the other 2 magnets on the inside and they should attract to the magnets on the bottom of the cup and stay in place.

5. Once you have placed all the magnets and everything is in place, repeat steps 1 through 4 to create the second headphone.

6. At this point, you can take one end of the wire on each headphone and twist them together to connect both sides. This part will end up connecting the two headphones together and it will act as the headband arc. (Make sure before you twist or solder the two wires together that they are sanded)

Step 4: Step 4: Plug and Play

Once your voice coil, magnets, and diaphragm are placed correctly you can work on attaching the headphones to the aux plug and decorate.
1. Taking both of the sanded ends of the wire connect it to the terminals of the aux plug. But before doing that put the cap of the aux plug through the wires so when finished with everything you can have all the wires secure. You have to connect the terminals with the ends of the wire because the aux is connected to your phone and the current will travel through the wires to the headphones. (Just like the picture below)

2. *Optional* Once that's done you can now go solder the connected ends of the wire to the terminals. When that's done you can also solder the top of the headphones where you twisted both parts together. You need to solder so you can make a much more firm and secure connection, but it isn't mandatory.

3. Bend both terminals inwards so you can now screw the aux plug cap on and enclose the terminals.

4. When everything is attached, now you can take any decorative tape or electrical tape and tape and the wires so they are protected/covered.

5. At this step, you can hot glue the connecting wire at the top to a headband and cover all of the headphones in felt or fabric. *Opitional* You can also add pipe cleaner at the ends of the cups to provide comfort.

6. Lastly, you can customize the headphones with whatever decorations you want to make them look nice.

7. After everything is completed you can plug the headphones in and listen to your song of choice and enjoy! Here is how the final product sounds: Video of headphones playing music

Step 5: Step 5: Troubleshooting

If you have trouble hearing anything through your headphones, look here.

When trying to successfully create headphones, you need to make sure all procedures are done thoroughly and thoughtfully. One thing you might want to check if you cannot hear sound out of your headphones is if the wires connecting to the terminals are correctly wrapped and sanded. If that's not the case and your sound is muffled or static then your voice coil might be loose or not attached to the cup correctly and there is air interfering with the vibrations. You might have to re secure the voice coil with electrical tape or start a new voice coil. If you also have a muffled or static sound then check to see if your wires might be touching or touching the same terminal. If none of the above work then you might be better off restarting and following the instructions step by step. Good Luck!

<p>Fun build. You could build a speaker into just about anything.</p>

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