Perhaps I can’t phrase the exact term. Tried with techo and so on.
A good suggestion would be appreciated.
Probably try frequency or vibration. Something similar.
If it is audio frequency you want search “tuner”.
Might or might not fit your needs - I found phyphox “Acceleration Spectrum” very instructive:
Waterfall chart shows shaking hand, then phone lying on desk, then electric toothbrush on desk.
Thank you, Mr. Frief, for your precious input. I noticed that I had misspelt Tachometer as Techometer.
I have changed the spelling.
Fortunately, I re-checked to find that there is no such app with a Tachometer tool in the F-Droid Repo. Had there been I would have to be very angry with myself for having wasted your energies in replying to my Typo-ed query.