These headphones are easy to make!
Step 1: Materials
You will need these materials:
3-arm lengths of 28 AWG wire.
2 paper cups / dixie cups
3.5 mm stereo jack AUX plug (with terminals)
Music source (iphone, ipod, etc.)
4 Neodymium magnets
Any type of sandpaper
1 Office Depot highlighter
1 Roll of Electrical Tape
1 pair of scissors or Wire Cutters
Step 2: Summary of Parts
You will need a plastic cup because it will act as your diaphragm. We chose the paper cup because it was more flexible and it vibrated more than other cups made out of different materials such as plastic and styrofoam. The diaphragm is what vibrates to move air and sound. The copper wire is used to connect the diaphragm to the AUX cable which connects to the sound source. We chose 28 AWG because the less AWG, the more thicker the wire is. The sandpaper is used to sand off the edges of the wire so it can be exposed. The magnets are used to make an permanent magnetic field in the diaphragm. The music source is obviously where the music will come from. The highlighter is what you will use to wrap the wire around to make the voice coil. Electrical tape is used to secure parts of the headphones such as the voice coil. Wire cutters are used to trim the wire.
Step 3: Assembly
Grab your AUX plug and make sure the terminals are showing.
Coil the copper wire loosely around the highlighter 40 times. Make sure about 30 cm is shown for each end of the wire. To finish the coil, tighten the coil by wrapping both ends of the wire around the coil. Next sand both sides of the wire. Make sure both ends are fully exposed. Then grab your paper cup and cut half off so the bottom is just left. Lay the voice coil down in the middle of the cup (outside) and then put a magnet inside the middle of the voice coil. Then put a magnet inside the cup. You should have something like the image above.
Then grab another cup and repeat the steps to make the other side of the headphone.
When you are done making both sides, solder one end of the voice coil to another end of another voice coil. (Ask a parent for help)
Then grab the other ends of the voice coils and thread them through the AUX plug terminals. Plug the AUX cable into a phone or device and play a song to test if the headphones work. If they don’t check your connections and make sure the wires aren’t touching each other because they will cancel each other out if they are in contact. Once you are confident that your headphones work, solder the wires to the AUX plug. (ask a parent for help)
Step 4: Magnet Positioning and Diaphragm Assembly.
The reason why a permanent magnet is needed in the middle of the voice coil is so the temporary magnet (voice coil) attracts and repels from the permanent magnet which causes the voice coil to produce sound. We decided to chose 2 magnets one on each side of the cup because neodymium magnets are really strong so we felt that 2 should be good enough. For the diaphragm, we chose to observe how the diaphragm affected the sound quality and found that the paper cup felt solid and the music produced from it didn’t have that many issues.
Step 5: Explaination
Our speaker should work because,
- We successfully wrapped our voice coil and it is the right size for our magnets. The coiled wire becomes the voice coil which acts as a temporary magnet inside the speaker.
- Our wire is fully sanded and securely attached to our aux plug. The sanding exposes the wire ends which connect to the AUX plug and the other speaker.
- Our diaphragm (plastic cup) is not damaged, the bottom fully moves forward and back.
- We chose 40 coils because when we tested 30 coils out, the noise was quiet and when we tested 50, the noise was loud and muffled. So we decided to just use 40 coils since it worked best.
- The magnets create a permanent magnetic field which changes polarity. The polarity changes when there is an alternating current which is when the magnets attract to each other and then repel, which is what causes the alternating current running through the voice coil and starts to vibrate which causes the diaphragm to move and make sound.
Step 6: Plug and Play
- Sanding the wire on both ends exposes the wire so it can connect to the AUX plug terminals and the other headphone speaker. If you don’t sand, then there wouldn’t be any connection.
- Sound waves are produced when the voice coil vibrates inside the diaphragm (which is the plastic cup).
- An alternating current is created when the voice coil (temporary magnet) starts to attract and repel from the permanent magnet (neodymium magnets).
- During our observation, we noticed that we could actually hear lyrics from our headphones. We also noticed that there weren’t any noises when we reached high pitches and most of the time, the audio quality was unaffected by the bass of the music.
Step 7: Troubleshooting
Q:What if my headphones don’t work?
A:Make sure that the wires aren’t touching each other or else they will cancel each other out. This also means to check that the wires twisted around the terminals aren’t touching each other. If it still doesn’t work, try adjusting the voice coil. You don’t want it to be snug on the bottom of the cup so it will be able to vibrate.
Q:What if I hear the music but it is faint?
A:Try to make sure all connections are secure and make sure everything is linked together. It could be something like the wires weren’t soldered together properly, or a wire wasn’t secured to the AUX plug.