Near Field Communication

Projects using the same technology found in travel passes, some new bank cards, and some electronic entry keys

This page is where I’ll post about anything I have done with NFC, or Near Field Communication, to give it it’s full name, having now got some equipment that supports it, a Samsung Galaxy S4 mobile telephone, I do also have the S II “P” version that includes NFC hardware, and the two do talk to one another, the newer of the phones has the support needed for contactless payments, ideal when getting lunch out at some places

On discovering some of the potentials of this technology it gave me some ideas of what I could actually do with it, so when I get some blank tags I’ll even include some how-to guides on how to make your own NFC tags, this should be a lot of fun

NFC reception on a shortwave radio

After doing some digging on Wikipedia, I found the radio frequency in use by NFC, this is 13.56MHz, a frequency that is readily tunable on most shortwave receivers.

This brings an issue into play, security. NFC will only work when the two devices are next to each other, however antennas can pick up the signal.  If only one device of the pair is powered, moving the unpowered device away appears to cut the transmission from the powered device.

The range I managed to obtain with my shortwave receiver acting as the “in the middle” device was limited to a centimeter or two.  My phone was used as the powered NFC device, a passive NFC device was used in this test, when the phone was reading data from the passive device the transfer could be heard over the speaker, when the transfer stopped the carrier was dead, moving the passive device away shut down the transmission from the phone. I will make a video demonstration of this at some stage using a device that does not contain any sensitive data, most likely a tag I have written myself with some nonsense text in it, so if it can be deciphered with the audio, it will just come back as garbage or nonsensical.

Keep watching

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