Materials (can all be found at Fry’s Electronics/Amazon/Home Depot)
1 roll of 28 AWG wire
2 Neodymium Magnets (2 cm diameter)
- 2 plastic SOLO cups
- 2 Glue sticks
- Sand Paper
- Electrical Tape
- AUX cord
- Post-it Notes
- Wire Cutter
Step 1: Tape Post-it Note
Wrap a post-it note around the glue stick. Put scotch tape on the post-it note to attach it to the glue stick, and also put some more scotch tape (inside out on the glue stick) so that you can wrap the wire around the glue stick easier.
Step 2: Wire Wrapping
Wrap the copper wire around the post-it note 45 times as close together as possible on the tape so you have a coil with the wire.
We chose 45 coils because it gave us the most crisp, clean, and high quality sound. We also used 45 coils because it was the best size to fit our magnet between and generally the more coils you have, the better the sound will be. We need a coil of wire because it acts like a voice coil which in turn will vibrate which will produce acoustical energy, and this is going to transfer through the air and to your ears into what we perceive as sound.
Step 3: Remove Post-it Note and Cut It Off
Remove the post-it note from the glue stick. Then cut the post-it note where the copper wire ends.
Step 4: Sanding Wire
Sand the ends of the copper wire on both sides, at least one inch. You should sand until you cannot see the red coating anymore. The reason you need to sand off the coating on the wires is because this coating is an insulator. An insulator does not let electric charges flow freely, and it also cannot conduct an electric current. Removing this coating/insulator allows the electric charges to flow and also allows the wire to provide a path for an electric current to travel through.
Step 5: Cut Hole in Cup
Flip your cup upside down. Cut a hole through the cup on the bottom in the center.
Step 6: Tape Magnet and Wire to Hole
Place the copper wire and your magnet on top of the hole and tape them firmly to the cup with electrical tape.
Step 7: Place Copper Wire
Place your copper wire on top of the magnet so that the magnet is in the middle of the copper wire, and tape the copper wire down so that both the magnet and the copper wire are on the bottom of the cup.
Step 8: Combine the Wires
Repeat Steps 1-7. You should have 4 sanded edges by now. Connect two of the sanded copper wire edges, each from different cups, to each other.
Step 9: Connect to Terminal
Connect the two sanded copper wires edges, that weren't previously connected, and attach them to the two terminals of the AUX cord (Be sure to connect them tight because this is where many connection problems may occur).
Step 10: Electrical Tape
Use electrical tape to cover up any bare copper wires for safety.
Step 11: Make It Cool! (Extra)
If you want, design two cups with paper, paint, or glitter to give your headphones that spark to make all the kids in the neighborhood jealous.
Step 12: Audio From Our Headphones!
Step 13: Final Product
One is without the electrical tape and paint.
Step 14: Troubleshooting
If the above steps do not work and you cannot hear sound try:
-rewinding coil more tightly
-sanding more thoroughly
-adding more magnets/coils to design
Step 15: 3 Main Components in Any Speaker
The three main components in any speaker are the voice coil, the diaphragm/cone, and the magnet. These components all help in the production of music. The voice coil provides a path for an electric current to travel through, and it strengthens the magnetic field. The magnet provides a magnetic field. The diaphragm/cone amplifies the vibrations, caused by the voice coil, to push sound waves in more directions.
Step 16: Why Voice Coils Vibrate?/How Vibrations Turn Into What We Perceive As Sound
Voice coils vibrate because there is an alternating current which switches direction in the wire. If wire is carrying a current, it becomes magnetic. If the current is alternating direction, the polarity of the voice coil is going to flip back and forth. This will in turn make it attract and repel away and towards the neodymium magnets. That attraction and repelling action will be the source of vibration of the voice coil. Vibrations are the source of all sound waves. The acoustical energy produced is going to transfer through the air and to your ears into what we perceive as sound.
Step 17: Results From Prototyping
Over the course of building these headphones, we made some realizations. We originally decided to try 15 coils first, then 30 coils, and then finally 45 coils. When we started off with 15 coils, the sound produced was of a very low, inaudible quality. 30 coils was a little louder and more clear than 15 coils, but 45 coils was the loudest and most clear of the number of coils we experimented using. With the magnets we only had 2 neodymium magnets on hand so we were limited to that. But when we tried two magnets on one speaker (in the beginning), the sound was better than with just one magnet. So, from this, we can conclude that more magnets (or stronger magnets) as well as more coils will improve the quality of the sound produced. We believe this is true because since magnets provide a magnetic field, more magnets would mean that the magnetic field would become stronger which will cause the voice coil to vibrate. Also, with more voice coils, there will be more vibration and the sound quality will improve. The tighter the coils are together the stronger the sound will be because there will be less interruption.