Rotor: Vibration Analyzer
ISO 20816 machine diagnosis
$2.99 · Designed for iPad. Not verified for macOS.
Rotor turns your iPhone into a working vibration analyser. Hold it against a
running motor, pump, fan or gearbox and read the overall velocity in mm/s RMS,
graded A to D against ISO 20816, with the machine class cited.
Then it tells you what is wrong, and shows you why it thinks so.
THE NUMBER IS REAL
Acceleration is integrated to velocity in the frequency domain, line by line,
with a high-pass cutoff. It is never cumulative-summed in the time domain, which
turns sensor bias into a wandering ramp. The graded overall is summed from a
rectangular-windowed spectrum so it stays Parseval-exact instead of
double-counting window leakage. If that means something to you, you already know
why most phone vibration apps are wrong.
VERIFY IT YOURSELF
Rotor ships with a self-test. It runs a signal whose answer is known
analytically through the same chain a real machine goes through, and shows you
measured against expected, side by side.
IT NAMES THE FAULT
Unbalance, misalignment, looseness, blade and vane pass, gear mesh with
sidebands, belt defects and electrical faults at twice line frequency. Every
verdict quotes the lines it came from and gives you the specific next step.
Check the coupling cold and hot. Inspect the impeller for build-up. Cut the
power and watch whether the peak vanishes.
IT KNOWS YOUR MACHINE
Ten presets set the ISO class, the plausible speed range, where to hold the
phone and which faults happen on that kind of kit. Enter the poles and supply
frequency off the nameplate and Rotor computes running speed including slip.
Count the blades or gear teeth, or measure the belt, and it draws those
frequencies as labelled cursors.
THREE AXES AT ONCE
High axial vibration relative to radial is how misalignment is told apart from
unbalance, so Rotor captures all three axes and shows which is worst.
IT REFUSES TO GUESS
If the sensor clipped, Rotor will not grade the capture, because a clipped
waveform invents harmonics that look like severe looseness. If the signal is at
the noise floor it asks whether the machine is running rather than awarding a
confident Zone A to a desk. If a bearing's frequencies sit above what your phone
can sample, it says so, because a missing cursor is not a healthy bearing.
WATCH IT GET WORSE
Log a reading and it keeps the full spectrum. Next month the trend line shows
the overall crossing out of green, with the ISO zone bands drawn behind it.
Rotor also compares against that machine's own baseline and lists the individual
lines that grew, in dB.
BEARINGS, THE HARD WAY
Envelope demodulation, done properly. Band-pass the bearing's resonance, take
the analytic signal by Hilbert transform, transform the envelope, and the defect
rate falls out of the noise. Rotor matches it against the computed BPFO, BPFI,
BSF and FTF to name which part is failing, computed from the bearing geometry.
FIELD BALANCING
Single and two plane by the influence coefficient method. Measure, bolt on a
trial weight, measure again, and Rotor solves the correction weight and angle
on a polar plot.
READ THE SPECTRUM
Orders axis, so 1x and 2x land on integers and a bearing line visibly does not.
Peak table with frequency, order and likely cause. Linear, exponential and
peak-hold averaging. Selectable resolution with the capture time shown.
Hanning, flat-top and uniform windows. mm/s and microns or in/s and mils, with
the ISO boundaries restated in both so the toggle never changes a verdict.
PRIVATE BY DESIGN
Everything runs on the device. No account, no cloud, no analytics, no network
access at all.
BE CLEAR ABOUT THE LIMITS
The built-in accelerometer is usable to about 100 Hz. That covers unbalance,
misalignment, looseness and ISO overall velocity on most slow and medium speed
machines. It cannot see most bearing frequencies, and Rotor says so in the
interface at the moment it matters rather than letting you believe a flat
spectrum means a healthy bearing. That honesty is the reason to trust every
other number in the app.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Ten additions, aimed at the job rather than the spec sheet.
REPORTS
One tap turns a reading into a PDF: the machine, the date, the ISO 20816 zone
with the thresholds it was graded against, the spectrum, the peaks, the
diagnosis with the evidence behind it, and the trend. Your name and company on
the footer. It is the artefact you are actually paid to produce.
LISTEN TO A BEARING
Envelope analysis needs kilohertz of bandwidth, and the accelerometer in a phone
stops at about 50 Hz. The microphone does not. ROTOR now records with iOS signal
processing switched off, picks the demodulation band by looking for the clearest
repetition rate, and finds the defect frequency on the machine in front of you.
A CURSOR THAT LANDS ON THE LINE
Tap the spectrum and drag. It snaps to the peak and reads back hertz, CPM, order
and amplitude, and names what it has landed on. Turn on the harmonic ruler and
the 2x to 12x comb appears, filled in where there is real energy, so a looseness
harmonic run is unmistakable.
ALARMS, AND WHEN YOU WILL CROSS THEM
Set alert and danger levels per point, from the ISO zones, from a multiple of
that point's own baseline, or by hand. ROTOR flags a crossing the moment you log
the reading, and when the history supports it, tells you roughly how long until
the level is reached.
ROUTES
Put your points in the order you walk them. ROTOR drives the round: what is
next, what it read last time, what is still outstanding, and when the round is
due again.
RUN-UP AND COAST-DOWN
Record while the machine spins down and read the amplitude against speed. A peak
on the way down is a resonance, and that is the difference between a machine
worth balancing and one that will never hold a correction.
BALANCING, FINISHED
Two-plane balancing with cross-coupling. Jobs are saved, so a phone call in the
middle no longer costs you another spin-up. Corrections split across bolt holes,
because you cannot drill at 217 degrees.
A GUIDED CHECK
Pick the machine, hold the phone where it says, get an answer in a sentence. The
same measurement and the same grading, with the controls out of the way.
SETTINGS
Metric or imperial, once, and it stays that way everywhere.
Everything still happens on the device. No account, no server, nothing uploaded.
The developer, Matthew Mesropian, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Matthew Mesropian
- Size
- 2 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © Integrated Software Technologies 2026
