STEPRSI Alert required

Hi,

Would anyone be so kind as to add an alert to this indicator that flags when it goes up or down through the 50 centreline.

I know it is a simple bit of coding but its beyond me, either a pop up screen or a sound would be great.

Any takers on this, I know its probably a simple line or 2 of code, I just cannot see how its done.

Help would be much appreciated