Snowy Mtn Observator Intervalometer doesn't integrate with the apps it controls. It runs on top of any other app and simulates the user pushing a button on the screen. The trick is to set the interval value (just click on the number, not the + icon) and then hit the Start (infinite) button and away it goes. If you tap the blue icon in the corner it'll minimize the app to that button alone so that it doesn't cover the screen, but will keep running (and can move it anywhere you want on the screen).
