By Anupum Pant
While doing a random experiment with the ordinary motor, a youtuber Andy Elliott who runs the channel mist8k (known for his awesome videos) mistakenly touched the 3.5 mm jack of a speaker cable to the motor’s wires.
This resulted in something very interesting. The sound being transmitted through the cable started coming from the motor. And consequently, he invented the very basic speaker. Then he made a video of him explaining how to make a speaker at home using just a copper wire, magnet, tape, jacks and a disposable plastic cup.
I first saw this on Gizmodo and I thought it deserved a mention in the engineering section of this blog. I can’t wait to try it myself and probably improve the “very basic speaker” to make a nice iPod dock in the future…
Here is what he does –
- Uncoils a copper wire from a component of an old PC, turns it into a small circular coil of the size of the circular magnet and then tapes it to the back of a disposable plastic cup.
- Then, makes a larger coil by winding it around a bottle cap and tapes it on top of the smaller coil.
- Connects one end of the larger coil to the tip of the 3.5 mm jack and the other end of the coil to the base of the jack. The other end of this wire having the 3.5 mm jack is also a 3.5 mm jack, which goes into the computer’s (or any player’s) speaker plug.
- Places a strong neodymium magnet on top of the coils and plays the music. That’s it!
The computer turns the sound signal into an electric current. This current flows into the jack and then into the coil. Thus, the coil produces a magnetic field of its own. This varying magnetic field coupled with the static magnetic field of the neodymium magnet makes the coil move. Which in turn moves the back of the cup (as it’s taped on it) and makes the air vibrate. As a result, sound is created.
Here’s the video where he teaches how to do it…