RPM Stroboscope is a simple stroboscope app that aids in determining the speed of rotating objects or the frequency of vibrating objects.
There are two modes that can be used, this is indicated by the label above the text field. When the label displays RPM, the value in the text field below displays the value in revolutions per second and the light flashes corresponding to that value. When shining the flashing light at a shaft that is spinning, it will appear to be stationary if the speed is the same as the value indicated.
Similarly, when in hertz mode the label will display Hz instead of RPM. In this case the value in the text field is converted to Hz and the light flashes corresponding to this value.
To switch between modes simply tap on the label. When in either mode, if you want to verify shaft speed or vibration frequency, you can tap on the text field and enter the value you want to verify.
If the speed or frequency is unknown, you can use the plus and minus buttons on either side of the text field to increment the value in order to find the speed or frequency. Long pressing on the plus or minus buttons will increment the value by 10 when in RPM mode and by 2 when in Hz mode.
If you double tap in an open area the plus and minus buttons will change to multiply and divide buttons. Tapping these will multiply by 2 and divide by 2. Long pressing the buttons will continue to increment by 2.
For best results, the shaft needs a unique feature so you can tell if the shaft appears stationary. If the shaft does not have a unique feature, referred to as a timing mark, you could simply mark the shaft when it is not spinning, that acts as the needed feature.