Android Question Phone spin - like a magic

[amorosik]

How does this phone spin?
Does it simply turn on the internal vibrator and then 'measure' the rotation?
The idea is great, but how does it technically work?

 

[John Naylor]

I say it's witchcraft but Google Gemini disagrees-


If you play a specific frequency or a loud, bass-heavy tone through your phone’s internal speakers, the physical movement of the speaker cone transfers kinetic energy to the phone's chassis. Because the phone is balanced vertically on a narrow edge, its center of gravity is high, making it highly unstable.

Here is exactly how it works and how you can replicate it:

The Science Behind the Movement​

• Vibrational Stick-Slip: When the speaker vibrates, the phone micro-bounces off the surface it is standing on. During the tiny fractions of a second when the phone loses full contact with the surface, friction drops to near zero.
• The Rotational Pivot: Because a phone’s internal components (vibration motor, battery, and speakers) are not perfectly balanced or centered, the vibrational force is asymmetrical. This causes the phone to naturally pivot or spin around its heaviest point or the side making the most contact.

How to Try It Safely​

If you want to test this out, you can use a frequency generator app or a website (like Szynalski's Online Tone Generator) and follow these steps:

1. Find a smooth, hard surface: A polished wooden desk, glass table, or smooth countertop works best. A rough or soft surface (like a mousepad or tablecloth) will absorb the vibrations and stop the movement.
2. Stand the phone up: Balance it on its bottom edge. (Note: This is much easier with phones that have flat, square edges rather than curved ones).
3. Sweep the frequencies: Start a tone generator at around 100 Hz and slowly slide the frequency up to about 500 Hz.
4. Find the resonant frequency: At a specific pitch, you will notice the phone start to buzz intensely and begin to rotate or "walk" across the table. This is the resonant frequency of your phone's specific chassis.
   
   

 

[amorosik]

How to start a 'tone generator' for example at 100 Hz ?

 

[John Naylor]

How to start a 'tone generator' for example at 100 Hz ?

Just search Tone Generator on Google Play - You'll find a few but the one literally called Tone Generator goes grom 20Hz to 22K Hz. I was going to try it myself but my phone case is bolted on and I can't stand my phone up with it on. Interested to find out your results!

 

[alwaysalearner]

Apparently, the original Cycloramic app (shown in Shark Tank) relied on a unique hardware characteristic of the Apple iPhone 5 - it used the phone's ERM (Eccentric Rotating Mass) vibration motor at specific frequencies to make the phone slowly rotate while standing on its flat edge. Modern phones generally cannot do this reliably because of different vibration motors (LRA - Linear Resonant Actuator), curved edges, camera bumps, and larger sizes.

 

[John Naylor]

Apparently, the original Cycloramic app (shown in Shark Tank) relied on a unique hardware characteristic of the Apple iPhone 5 - it used the phone's ERM (Eccentric Rotating Mass) vibration motor at specific frequencies to make the phone slowly rotate while standing on its flat edge. Modern phones generally cannot do this reliably because of different vibration motors (LRA - Linear Resonant Actuator), curved edges, camera bumps, and larger sizes.

Interesting! I think I have an old iPhone 5 buried in a junk drawer somewhere I must dig it out!