It would be something like this.
Sprite variable (knob)= greater than 0 but less or equal to 360.
Set angle to sprite.knob
Sprite variable (set) = 1 & mousedown
Set Sprite.knob to distance(mouse.X,mouse.Y,Sprite.X,Sprite.Y)
(Devide this by an x amount if the result is to high)
Mouse left click on sprite.
Add 1 to sprite.set
Then for resetting the sprite when unused.
On left mouse button released.
Set sprite.set to 0
U have to test it of course but this is how i would handle it.