This is pretty silly. No casinos or card rooms let you have a phone/device at the table.

That aside, you need to have a special marked deck. People have tried something similar with flourescent ink and special glasses. I think professional shuffling devices have some kind of built in blacklight check now for this. IR is a bit better since its harder to detect without a camera. You would still need to have a tub of ink and manually mark the cards though.

You'd basically need to have the dealer in on it, and if that is the case you don't really need the device at all.

A more interesting method from a few decades ago that actually worked was "edge sorting". Because of printing/cutting one could determine certain cards. http://deadspin.com/how-phil-ivey-beat-or-maybe-cheated-a-ca...