Making a Walnut Guest WiFi Coaster

I was recently reading about the 13.56MHz NFC protocol and the standard tags you can write and read from your phone, when I realized that one of the features of NFC is that you can program tags with WiFi credentials, via the concept of NDEF records, which let you encode URLs, vCards, plain text, etc.

I thought this would be a good gift idea, so I bought some NFC tags on eBay, and then built a coaster around it using walnut and sand blasted glass.

Video:

The main thing for building one of these is getting some NFS tags, which you can easily find on Amazon, and writing your WiFi credentials to it as an NDEF record, which is possible using various phone apps, including the TagWritter app from NXP, which is surprisingly good for being a vendor app.