Most people’s experience with NFC and RFID is from using smart cards to unlock office building doors. But, the same qualities that make the technology ideal for smart cards — like the small size, low cost, and not needing a power source — also makes them perfect for applying directly to your fingernail! You could then just put your fingernail near your phone to perform all sorts of tasks, like unlocking your phone or turning on the flashlight!
If that sounds interesting to you, Tanya Fish has a great tutorial over on Make: that covers how to embed NFC tags in your acrylic fingernails. Unfortunately for you iPhone users, this probably won’t work for you; Apple locks down the NFC capabilities — though you may be able to get around that with an app. If you’ve got an Android device with an NFC reader, you just need to install an NFC app. Fish recommends NFC Tools and/or NFC Tasks, which I agree with after some brief testing.
Your choice of NFC tags is important too, as they need to be small enough to fit on your nail and compatible with your phone’s NFC reader. Fish used the the NXP Mifare Classic 1K, which worked well in my testing. It comes in a lot of different form factors, by the small, flexible, adhesive-backed tags work best. They’re a bit hard to source, but Pimoroni has some round ones in stock, and will be carrying rectangular LED-equipped versions soon. They should run you less than $6 for a pack of five.
From there, it’s just a matter of placing them inside fingernail acrylic and setting up tasks on your phone to be triggered by the tag. You can even use them on your Raspberry Pi or BeagleBone with Adafruit’s PN532 NFC breakout board. Fish’s finished fingernails look great, and even light up with an LED when they’re placed near an NFC reader!