Belt Tension Frequency Meter

Check the vibration frequency of a stationary belt using your phone’s microphone. The app analyzes each pluck on the device, captures three stable readings, and shows the average frequency, repeat range, and signal confidence.

Enter the target frequency range from the belt or machine manufacturer to see whether the measured average is below, within, or above that range. If the manufacturer provides linear density and you measure the belt span, the app can also show an input-based tension estimate using T = 4mL²f².

How to use
• Switch off the engine and all power.
• Wait until every pulley and belt has completely stopped.
• Hold the phone near the middle of the belt span.
• Measure one pluck at a time until three readings are captured.
• Repeat the measurement if the repeat range is above 3%.

Safety and accuracy
Never measure a moving belt or reach into rotating equipment. This app does not diagnose belt condition and does not provide manufacturer target values. Background noise, phone microphone processing, distance, belt shape, and input accuracy can affect the result. Confirm critical work with the manufacturer’s procedure and a calibrated sonic tension meter.

Privacy
Microphone audio is analyzed in real time on your device. Audio is not saved or uploaded. Measurements are stored only on your device when you choose Save. No account is required.

The app contains banner ads and may show an interstitial only after a completed result when starting a new measurement. Ads are not shown during measurement.

Recent changes:
Stability and reliability improvements.