More than 2 taps with tablet as server OR recognising users with tablet front end + server back end

I have a nexus 7 and an arduino mega with 6 taps. I run the server on a PC and have the mega plugged in to the server.

I can use the tablet front end to see remaining volumes and previous pours but I would love to get some user stats and possibly NFC auth.

Can the tablet app recognise a mega? If not, is there any way to get it talking to the server to register a user pour?

I am sure it would work with the tablet as the server using a UNO but i can’t get more than 2 taps with the UNO.

Thanks for any replies

Once I set the serial on the mega this worked