How to write expression in such case - 9

[Suraiya A]

Hi,

I want the hand to move/wiggle only between 0/360 to 180. I dnt want it to cross 180. How will I write expression in such case using wiggle.

(I had to reduce the screento gif export color option only to 12, otherwise file size is too big to upload, Adobe dsnt allow me to upload gif , thts why the gif is acting weird. am sorry :I ) 

Thank you. 

only this semi circle

[Dan Ebberts]

I think I'd set it up with a slider (set to 100 initially) to adjust the overall range, and then use an expression like this:

w = wiggle(0.5,180)-value;
offset = -90;
mult = effect("Slider Control")("Slider")/100;
offset + w*mult

Then adjust the offset variable and the mult slider to get exactly what you want.

[Suraiya A]

Thank you so much, could not figure out the math yet. Thank you so much for showing how to write it.