NFC on android, tags and message compatibility

Question

I'm developing an android application which makes use of NFC. First I record the nfc-message to a tag, and then complete some action, when user taps the tag for the second time.

But I cannot control what type of tag the user will purchase..

My question is .. how do I guarantee that my writing/reading application will work for any tag the user purchaces?

What is the message format I should use to guarantee that? I'd like to have an option of writning multiple NFC items into one mesaage. Should I ask user to buy only certain types of tags?

Thank you...

Answer 1

There are two aspects:

a) stay with the NFC specifications to format and store the data on the tag. This helps to make the tags compatible with various tags / chips

b) the main issue to consider is the available storage space which the tags offer. This can be very small (e.g. 48 byte on a NXP Mifare Ultralight), or up to some kbyte. So can either try to limit your data to make it fit even on the smallest tags, or you define a minimum size and you request your users to use only tags of that size or larger. In our app you may want to check the tags size before you try to write to it, otherwise it may fail.

You can place several records into a NFC message, which may accommodate your need for multiple "items". However, the memory size of the tag will be the limiting factor.