Researchers at the University of Washington (UW) have pioneered a technique where everyday objects can be embedded with transmitters that piggyback ambient FM signals to send data to nearby smartphones and radios using almost no power.
The technique makes used of backscattering, which is the reflection of waves, particles, or signals back in the direction they came from. The system uses a low-power reflector to encode specific audio or data on top of reflected signals from an existing FM broadcast, with the data sent on an adjacent band so as not to interrupt any current radio transmissions.
The key benefit of the technology is that it has an extraordinarily low level of power consumption, meaning that it can easily be incorporated into everyday objects at a low cost...
The antennas are made of thin copper tape and can be simply embedded into objects like advertising posters or articles of clothing. Initial demonstrations of the technique showed the total power consumption of a transmitter embedded into a poster to be as little as 11 microwatts – an output that could run uninterrupted off a small coin-cell battery for two years...
The UW team has produced two working proof-of-concept prototypes demonstrating the technology. The first was dubbed a "singing poster" that transmitted portions of a band's music to a smartphone up to 12 ft (3.6 m) away, or a car up to 60 ft (18 m) away. more
FutureWatch: Cheap, difficult to detect, short-range, long-term bugs. The traditional police "wire" invisibly woven into undercover investigators' clothing. ~Kevin
