piano teacher ? (finger exercise ?)

[gardenmom5]

What is a good exercise to strengthen the pinky?  (I have Hanon, and have done some.  Any particular ones? frequency?  number of exercises per day?)

I'm also doing the "L" one that is supposed to develop independence.

[Dmmetler]

This is really awesome, and can be used with the rhythms of any technique piece/exercises https://www.teachpianotoday.com/2015/03/09/the-amazing-fingercise-cup-a-diy-tool-for-fixing-your-piano-students-collapsing-finger-joints/