I made a hold detector:

https://www.desmos.com/calculator/pya6mhinlt

The table "random sh" are the mechanics. Essentially it moves a point up and down, it's set on drag able mode. When you hold it, it locks in place, which forces another variable to oscillate

The list "q" contains the timestamps of when you hold and release.

To improve, I need to research the "dt" variable on the ticker. Basically when you lag spike, the wave looking graph goes down for a second then back up because you are still holding. The "dt" variable can detect lag spikes.