My question is related to this post
IMHO the user sliding the finger off the screen can easily take the finger to a place where the slider is no longer available. So, they will move their finger back towards the slider and then will only know they truly got there if the slider vibrates or rings.
My Android device has several UI elements (such the four volume slider controls which pop up when you hit the volume keys) UI sliders for blind people: as the person (who is blind), moves their hand along a phone surface, and comes in touch with the slider, the slider knob should immediately jump to the position where the user's finger is and make a sound.
Any ideas, comments, or suggestions?