For DSLR I guess you'd need a tripod with a ball head that can be tilted down (so the phone can be pretty stationary on the surface) or some rig for top-down shooting. Then you'd need to pick on a lens that would give you the framing you want at the distance you're shooting from. And also that can focus on the phone if the camera is close. Also, manual settings so you can sync the shutter to screen refresh rate to eliminate flicker (if there's any), to get a solid exposure and to not have the focus drift around.
I would but I'd like the audience to see the experience with the hands in the view. To give it more of a human feel. Similarly no apple commercials ever featured just the screen showing. But usually one hand holding the phone and the other interacting with the app.Why not just use a recorder app on your phone. I use AZ Recorder.
What I mean is that it depends on what distance the camera will be from your surface and how much of "white space" you want and how much space you want the device to take. If you're filming different sized devices, either an adjustable lens or and adjustable tripod would probably be a good choice.Thanks for the reply, But Im not that big of a DSLR enthusiast what do you mean by a lens that gives me the "framing" I want and what kinds of lenses are good up close ? .
So to recap I need a tripod with a ball head,these lenses and also I need to sync the refresh rate of the camera with the refresh rate of the phone screen itself.