#persistent
coordmode, mouse, screen

mousegetpos, sx, sy

settimer, check, 250
return

check:
mousegetpos, cx, cy
if (cx != sx or cy != sy)
{
  ; mouse has moved, calculate by how much
  if (cx > (sx+50) or cx < (sx-50) or cy > (sy+50) or cy < (sy-50))
  {
    msgbox, mouse has moved more than 50 pixels
    mousegetpos, sx, sy ; get new mouse position
  }  
}      
return