Turning My CASIO F-91W Into a Contactless Payment Device
Summary
This article documents a hardware-focused NFC research project that repurposes a CASIO F-91W into a contactless payment device. It covers NFC fundamentals, tool-based exploration (NanoVNA, Proxmark3), and a step-by-step look at testing, tuning, and assembling a customized payment-capable watch, with an emphasis on ethics and responsible use.