An Unexpected Application for a Fidget Spinner (Rotating Field Direction Measurements)
Sometimes the most useful equipment is the equipment you forgot you had.
The Discovery (09:47)
I was looking for a spare AA battery in my desk drawer—the one I have not opened since approximately 2019—when I found it.
A fidget spinner.
I stared at it for several seconds, trying to remember how it came into my possession. Then I remembered: 2017. The year when every person under the age of 25 seemed to be spinning these devices. A colleague at the university (Dr. Petrov, visiting lecturer, condensed matter physics) had given me one as a joke. “For when your experiments get boring,” he had said.
I had never used it. Not once. It went into the drawer, and I forgot about it entirely.
But today, holding it in my hand, watching it spin with surprising smoothness despite seven years of neglect, I had a thought.
A potentially useful thought.
The Principle: Rotating Field Direction
For those unfamiliar with three-phase electrical systems—which is most people, and reasonably so—I will explain briefly.
In a three-phase alternating current system, the three phases (L1, L2, L3) are offset by 120 degrees. This creates what is called a rotating magnetic field. The field rotates in a specific direction, determined by the phase sequence.
Why does this matter?
For most household applications, it does not. Your refrigerator does not care. Your lamp certainly does not care.
But for three-phase motors, the direction of the rotating field determines the direction the motor spins. Connect the phases incorrectly, and your motor runs backwards. In industrial applications, this can be catastrophic. A pump running backwards does not pump. A conveyor belt running backwards creates chaos.
In my apartment, I have no three-phase motors. I have a single-phase connection like any normal residential unit.
But I also have curiosity. And now I have a fidget spinner.
The Modification (10:15 - 11:30)
To detect rotating field direction, one needs:
- Something that can rotate freely
- Something magnetic
- Proximity to a rotating magnetic field
The fidget spinner satisfies requirement #1 admirably. The bearings, despite their age, are still functional. I measured the free-spin time: 47 seconds from a moderate initial impulse. Acceptable.
For requirement #2, I attached a small neodymium magnet (salvaged from a broken hard drive in 2014) to one arm of the spinner using electrical tape. This creates an asymmetry—the magnetized arm will be pulled by the rotating field, causing the spinner to rotate in the direction of the field.
For requirement #3, I would need access to a three-phase system.
I do not have three-phase power in my apartment.
But I do have a transformer.
The Experimental Setup
My old variable transformer (ЛАТР-1М, Soviet manufacture, 1983) can create a rotating magnetic field when connected in a specific configuration. It is not truly three-phase, but for demonstration purposes, it produces a measurable rotating field component.
Setup:
- Fidget spinner with attached magnet, suspended on a thin thread (0.3mm fishing line, borrowed from Dr. Yevgeny’s grandson Dima during the radio receiver incident—he never asked for it back)
- Variable transformer, set to low voltage (safety first)
- Distance from transformer: 15 cm (determined through trial—closer caused excessive oscillation, farther produced no response)
- Video recording for analysis (smartphone, mounted on stack of books)
Hypothesis: The spinner will rotate in the direction of the transformer’s field rotation.
Results (12:00 - 14:30)
I conducted 12 trials. The results were surprisingly consistent.
| Trial | Field Direction | Spinner Response | Rotation Time (full) |
|---|---|---|---|
| 1 | Clockwise | Clockwise | 3.2 seconds |
| 2 | Clockwise | Clockwise | 3.4 seconds |
| 3 | Clockwise | Clockwise | 3.1 seconds |
| 4 | Counter-CW | Counter-CW | 3.3 seconds |
| 5 | Counter-CW | Counter-CW | 3.5 seconds |
| 6 | Counter-CW | Counter-CW | 3.2 seconds |
| 7 | Clockwise | Clockwise | 3.3 seconds |
| 8 | Clockwise | Clockwise | 3.4 seconds |
| 9 | Counter-CW | Counter-CW | 3.1 seconds |
| 10 | Counter-CW | Counter-CW | 3.4 seconds |
| 11 | Clockwise | Clockwise | 3.2 seconds |
| 12 | Clockwise | Clockwise | 3.3 seconds |
Success rate: 100%
The fidget spinner correctly indicated field direction in all 12 trials.
I am unreasonably pleased by this.
Practical Applications
Are there practical applications for a fidget-spinner-based rotating field detector?
Honestly: not really.
Proper phase sequence indicators exist. They are inexpensive. They are reliable. They do not require fishing line and a magnet salvaged from a dead hard drive.
But that is not the point.
The point is that a toy, designed to occupy restless hands, can be converted into a functional scientific instrument in approximately 75 minutes using materials found in a desk drawer.
The point is that understanding principles allows improvisation.
The point is that I spent a Sunday afternoon conducting experiments with a fidget spinner, and I regret nothing.
Day 4 Data (Collaboration with Ruslan)
I should note that between experiments, I maintained my measurement schedule. Day 4 of our atmospheric pressure correlation study:
| Time | Pressure (hPa) | Frequency (Hz) | Notes |
|---|---|---|---|
| 06:00 | 1019 | 49.98 | Clear morning, cold |
| 08:00 | 1019 | 49.97 | Ruslan confirmed |
| 10:00 | 1019 | 49.96 | Stable (fidget spinner experiments began) |
| 12:00 | 1018 | 49.95 | Ruslan confirmed |
| 14:00 | 1018 | 49.94 | Slight decline |
| 16:00 | 1017 | 49.93 | Continued decline |
| 17:00 | 1017 | 49.93 | Ruslan confirmed |
| 18:00 | 1017 | 49.94 | Stabilizing |
| 20:00 | 1018 | 49.95 | Rising |
| 22:00 | 1018 | 49.96 | Baseline |
A stable day. Pressure and frequency moved together, as they have been doing. The pattern is becoming visible, but I will not draw conclusions yet. 26 days remain.
Ruslan’s Response
I emailed Ruslan about the fidget spinner experiment. His reply (received 21:15, 489 words):
Subject: “Re: Improvised rotating field indicator”
“Anatoli,
This is excellent. I once used a compass and a small motor to detect phase reversal at the postal sorting facility. The official equipment was ‘being serviced’ for three weeks. My compass-and-motor device worked in 20 minutes.
The postal service did not appreciate this. They said I was ‘not authorized to create measurement devices.’ I pointed out that I was authorized to ensure the conveyors ran in the correct direction. They said these were different things.
They were not different things.
Your fidget spinner is a worthy successor to my compass motor. I approve.
Day 4 data attached. The parallel decline continues. I have begun hand-drawing the correlation plot. The graph paper was a good purchase.
Ruslan”
I appreciate that Ruslan understands.
The Fidget Spinner’s New Home
The modified fidget spinner now hangs from a hook near my transformer. It is no longer a toy. It is equipment.
I have labeled it: “Rotating Field Indicator (Improvised), 2026”
This is perhaps excessive. But proper labeling is important.
Reflection
Today I:
- Found a forgotten object from 2017
- Converted it into a functional instrument
- Conducted 12 successful trials
- Maintained my measurement schedule
- Received validation from a fellow improviser
Mrs. Kuznetsova’s cat treats were delivered this morning, as planned. I left them at her door with the note. Two hours later, I heard Misha meowing—differently than usual. I choose to interpret this as appreciation.
The battery I was originally looking for remains unfound. This is acceptable. The fidget spinner was a better discovery.
Current status:
- Pressure (22:00): 1018 hPa
- Frequency (22:00): 49.96 Hz
- Rotating field indicator: Operational
- Days remaining in study: 26
- Fidget spinners repurposed: 1
Tomorrow is Monday. The measurements continue. Perhaps I will find other forgotten objects with unexpected applications.
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