iPhone Screenshots


This app detects the RPM of an electric motor based on the sound or vibration it makes, and from the RPM it calculates the percent of full load on the motor. This app does not work with all electric motors. This app only works if the motor is making a clear tonal sound or vibration whose pitch is related to the speed of the motor. It will not work if the sound is atonal or masked by too much noise. Please download the manual from our support website


to understand the limitations of this app before buying it. There is also a video showing how it works.

Although valid results may sometimes be obtained with the built-in microphone in iOS devices, in some cases better results can be obtained with an external contact microphone, such as the ones used to tune guitars in a noisy environment. By clipping a contact microphone somewhere on the motor the vibrations from the motor can be sensed directly with less noise.

Monitoring the RPM of a motor over time can be a useful preventative maintenance tool for motors used in critical industrial applications.

AC induction motors run at a speed somewhat below their synchronous speed. The degree of slippage from synchronous speed depends on the mechanical loading of that motor. When the loading increases, this app can detect the slight drop in motor speed and indicate when loading is increasing.

What’s New

Version 1.1

* iOS sound compatibility issue fixed.
* Configuration for harmonics of motor sound added.
* Signal analysis algorithm improvement for higher accuracy in RPM measurements.
* Improved help pages.

Ratings and Reviews

5.0 out of 5
1 Rating

1 Rating

juniorelectronicengineer ,

INSANELY precise app.

This app is AWESOME. I am not even measuring an induction motor. As long as your motor makes a clear tonal sound, and you adjust the settings according to the known specs of your motor, you will get an EXTREMELY precise measurement. I do have a tachometer and just wanted to see if this app worked. The reading I got off of this app was less than 5 RPM off of the reading on my tachometer. This app is perfect. The “load” setting needs a bit of work though. I Use this every day!


Real-Time Specialties, inc.
4.9 MB

Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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