After you're done polishing/publicizing your app, you should write a blog post describing the transition from developing trading algorithms to developing public service/safety apps :)
:) I was lucky enough to work for a great company [1] that was very techy so in terms of the culture it wasn't much of a transition. The hardest part (which I am still working on) is developing for anyone out there instead of internal use. I rarely had to think about UI/UX/User Behavior previously.