> I should explain how NFC works: Your phone emits a small magnetic field several times a second. An NFC card picks up on that field, making your phone act like

> I should explain how NFC works: Your phone emits a small magnetic field several times a second. An NFC card picks up on that field, making your phone act like a tiny wireless charger. The card never actually transmits a message back to your phone. Instead, it changes how much energy it absorbs from the field, and your phone detects those power dips and converts them to binary data. Most NFC tags use this harvested energy only to run their internal circuitry, but some NFC chips are able to take excess DC voltage and route it out to external hardware. Can somebody explain how this actually works (Physics + Technology) with pointers to further resources? I have been meaning to look deeper into "Energy Harvesting Systems" and running a MCU using that but never really sat down to research it properly. Some links; University of Washington - WISP (Wireless Identification and Sensing Platform) - https://sensor.cs.washington.edu/research/wisp_1 https://sensor.cs.washington.edu/research/wisp_1 Perpetually Powered Energy Harvesting Systems Using the MSP430 MCU - https://www.ti.com/video/3870842958001 https://www.ti.com/video/3870842958001