Add `type`/`usage` attribute (`spool`, `swatch`/`sample`/`reference`, `print`, ...)

[drothmaler]

I'd like to embed NFC Tags with OPT in my filament swatches.

Of cause I could just use the same tag data as on spools, but some of the data just makes no sense there. If we had some kind of tag type, software tools could automatically omit them. But more importantly printers could distinguish between them, because the should only react to a Tag, that actually is on a spool, and not accidentally read/write my swatch tags.

Also those simple round NFC tag stickers are so cheap on Aliexpress and other platforms, that some people might just stick them on their prints, or embed them; to be able to identify the used filament later.

Probably people will come up with more ideas/ways on how to use OpenPrintTags, so I think it will be good to create a way to differentiate between those tag usages.

[CZDanol]

Hello and thanks for the idea :)

This wouldn't actually be nearly as hard to implement. The core of the OPT structure, together with our Python and C++ libraries, are quite universal, and the list of fields is separated from the format itself.

The readers identify the OpenPrintTag tag through the MIME type information in the NDEF record. So, to prevent cross-talk, we can simply change the MIME type for the swatches (from ˙application/vnd.openprinttag˙ to for example application/vnd.openprinttag.swatch or something; note: if someone decides to do this on his own, DO NOT use the vnd.openprinttag official vendor tree, that is reserved by us).

This all (MIME type + field) is provided to the libraries through this configuration file – so we would simply create a different config file, omit the aux region (because that one wouldn't make sense for the swatches), change the mime type, and probably reuse the same main fields region.

All the Python scripts then have the --config-file switch that would allow them to work on this different structure.

I can't say that we will really do this, though. Let's first let the idea sit for a bit and see if it gains some public interest.

[ganti]

I really like this idea for filament swatches. Over the years, we try many different filaments from many manufacturers. We tend to remember the brands we use frequently and like but forget those we have only tried once. This is why I find a swatch collection so useful. it helps me remember past but rarely used filaments and makes it easier to repurchase specific spools later.

When https://3dtag.org contains a database of all known spools some day. it would be great to download a swatch configuration directly from there. This would make writing the tag much easier.

From a user’s perspective, the ideal solution would be to integrate this directly into the Prusa mobile app. From there, the data could be shared with an NFC writer or it may be written directly within prusa app. Then it is possible to physically write an NFC tag for filament swatches in just two clicks.