-----
How fast can a Fidget Spinner spin? Well, it depends on what spins it. Let's use compressed air.
That sounds fast, it's actually scary to hold!!! But how fast?
-----
To make the measurement we used a simple LED as a sensor. A bright light shines down onto the LED. The arms of the Fidget Spinner block the light as they move over the LED creating electrical pulses.
-----
The sensor LED is connected to a Tektronix MDO4104C to measure the pulses. The scope (along with a few thousand other features) allows an engineer to quickly study waveform measurements with cursors. After a little math we get our answer; well over 10,000 RPM.
That's fast!
-----