Motor Pitch Analyzer app for iPhone and iPad

MotorPitchAnalyzer (MPA) is an app for measuring small motor rotation speed in real-time. 
Just bring the motor close to your smartphones microphone for easy measurement! 
You can improve accuracy by narrowing the measurement range. 
The app shows the motors maximum rotation speed based on stable rotation and frequency intensity. 
You can also quickly check for shaft runout and brush conditions by viewing the motor sound waveform in real-time (※ for rough guidance). 
Please measure in a quiet place for accurate results. 
Note that measurement accuracy may vary slightly depending on your iPhone or iPads microphone performance.