3G, NFC, Bluetooth and Wi-Fi are all well and good, but there's perhaps an even geekier wireless protocol in town—and it uses magnetism for your phone to communicate.
Everyone's most beloved of science phenomena since the high school science fair, the neat thing about using magnetism to get your phone transmitting data is that it already has the sensors on board. The developers of Pulse are using the magnetometer on phones, usually used to measure direction suing the Earth's magnetic field, to receive information by varying the magnetic field in the surroundings of the phone. New Scientist explains how it works:
By encoding data in a varying magnetic field they have shown they can transmit anything from a web address to a MIDI music sequence from the electromagnet to the phone. That means a small electromagnet embedded in an interactive street poster could do the job of a printed QR code, say, but with the benefit of an advertiser being able to regularly change the URL.
So far they can't shift much data at a time: they've only achieved 40 bits per second so far, and even then it only works over a range of 2 centimeter. But the team suggest that it could be used to make NFC transactions—which can be intercepted up to 20 centimeters away—more secure, by providing a handshake when the device is an inch away from the payment terminal.
Regardless of application, though, I love the idea of my phone using magnetism more. The research is to be presented at the annual ubiquitous computing conference in Seattle, Washington in September. [New Scientist]