Wavevibe optical waveform analyser (D.I.Y.)

Most of us have heard sound, but have you ever wondered how it looks 👀?

This week we'll be trying something a little different, and instead of journeying to far reaches of space 🌌 or teleporting through dimensions ↘️, this week we're gonna talk about something that you can actually try at home 🏠!

Waveform analyser? What's that you ask? Well, it's a fancy term that I've used to describe a device that we're gonna build ✂️ that'll allow you to visually observe sound waves 🌊! And if you don't find that appealing enough already, just wait till you see the images of a real model that I made at home. 😏

Materials:

1. A balloon - Literally a normal balloon, nothing special. 🎈🎈🎈

2. A Speaker - Preferably with Bluetooth (wired will work too). Just make sure it's a relatively small one. 🔊🔊🔊

3. A little mirror - You can find this in any craft store (or maybe from a fancy dress)

4. A cardboard tube - If you can't find one, just find anything that resembles a tube and is wide enough to fit the speaker inside. 🗂

5. Some basic craft materials - Scissors, tape, etc. ✂️✂️✂️

6. Laser - Any laser you can find. 🔦

The making:

1. Cut off the tip of the balloon and stretch it over one end of the cardboard tube to form a membrane. 🎈

2. Use some tape to secure the balloon over the mouth of the tube.

3. Stick the little mirror using some glue/tape at the centre of the membrane. ✂️

4. Place the speaker at the other end of the tube making sure that it faces towards the membrane. 🔊

5. Point the laser at the mirror such that the reflected beam is projected onto a surface (wall). Place it in this position. 🔦

That's it!

This is how it should look:

Now that the set up complete we can actually get to the experiment 🥳🤩! Download this app, I'll tell you what to use it for later...Frequency Generator

Connect your smartphone to the speaker and play some music. What do you observe? Some crazy shapes 😮! Well, that's cool but it wouldn't make any sense if you just had random patterns being projected. So let's control it now. The app I asked you to download allows you to play a wide range of frequencies, and crucially it allows you to control them. (Feeling the scientist vibes? 🤓)

Now pick a frequency, any frequency (Preferably about below 500Hz, but you can experiment with others too). Do you see some shape emerging 😯? If you don't, just increase the volume or try changing to a lower frequency. 🔈🔉🔊

If you look carefully 🧐, the amplitude (volume) of the sound controls the size of the projection, and the frequency controls the shape. Now let's keep experimenting! What if we play multiple frequencies together? Try it out!

You will observe that the pattern now appears to have motion added to it, almost as if you were looking at a video being projected 🤯🤯🤯! Keep experimenting with different frequencies and mix them up, I assure you that you will be surprised by the almost alien-like patterns you create. 😶

Now, how were these projections formed? Let me explain. 🤓

Sound is essentially our perception of vibrations. The speaker works by setting air molecules into vibratory motion 🔊. This in turn vibrates the membrane and the mirror along with it. Now on beaming the laser at the vibrating mirror, we obtain a projection of the laser. And since the mirror is vibrating too, the laser point follows the path of the vibration. This is what creates the various patterns you see. 💡

Every frequency has a particular type of vibration, mapped by the laser pointer onto the wall producing unique shapes for each vibration. 📈📉📈📉

Now tell me why does the amplitude control the size of the projection? Any guesses? It's because the louder the sound the greater the amount by which the membrane moves (we call this displacement). And the greater the displacement of the membrane the larger the projection (since the laser point can now be moved by a greater distance). 😲

And lastly, why does the overlapping of different frequencies of sound waves produce the apparent movement of the image? That's because now the different frequencies interfere with each other. If one frequency would try to cause a horizontal ➡️ movement, and the other tries to cause a vertical ⬇️ movement of the laser point, the resultant direction of the point is diagonal ↘️! Similarly, on continuously playing the frequencies, different interferences cause more complicated motion of the point that caused your mind to be 🤯🤯🤯.

And there you have it! Now next time you party, make sure you have your Wavevibe analyser ready or rock the show! 😎😎😎

Here's the one I made (Please excuse the poor video quality, cameras aren't great in the dark!) 😅😅😅:

Here's a video that demonstrates this experiment:

• Demo by Steve Mould

(Also take a look at his other videos, they are awesome)

When you make a project, be sure to let me know in the message box. I'll get in touch with you and we'll have your project uploaded to the site soon! Let others be amazed by what you've made!

PS: Leaving me a positive review would truly mean the world to me and encourage me to do more of what I do. I truly enjoy making these blogs and I would love to hear what you think about them. If you’ve got any ideas or suggestions from future blogs, put them down in the suggestion box and if chosen, I’ll add your name to the credits of the blog! Thanks for reading!