There's an app for that, oh and some plastic

Interbike the time of year when the interesting and odd products show up. A product for those who haven't sorted out limit screws... Check it out at bike rumor if you dare http://www.bikerumor.com/2015/10/01/bike-needs-a-tune-the-otto-tuning-system-has-an-app-for-that-with-smart-phone-based-derailleur-adjustment/