Most business cards are not technically capable, thus the given page will document only “custom”, “unique”, or “one-off” business cards that are custom tailored to have a level of technical capability. With this, one cannot determine any level of “common” OSes or CPU architectures.

All this is accomplished on a very small 8MB flash chip

An interesting creation made for $2.88, complete with some interesting little programs that are more than mere novelties. Great proof of concept for extremely cheap Linux programming. Nowadays, the price for this has probably risen, but it could still have interesting potential for the purposes of learning embedded Linux.

https://www.thirtythreeforty.net/posts/2019/12/my-business-card-runs-linux/

https://www.thirtythreeforty.net/posts/2019/12/designing-my-linux-business-card/