— Sony's Tokyo research lab has found a way to connect headphones to portable music and video players without the need for fiddly wiring. They simply feed an audio signal straight through the listener's body.
Existing wireless headphones use Bluetooth radio, but this means pairing two devices beforehand and is prone to interference from other equipment. Another approach infra-red relies on line-of-sight, which is rarely practical.
The new system uses the listener's body as a capacitor that carries a tiny electrostatic charge. A music or video player sends a fluctuating signal to a conductive cloth pad such as a wrist band and this slightly charges the wearer's body. A pair of conductive ear pads in the headphones pick-up the signal and rapidly convert it back into sound.
Just a few millionths of an amp flow through the wearer's body, so there should be no nasty tingling effect. To convert the small charge into good quality audio, Sony uses a high frequency signal, which is digitally switched to carry data at 48 kilobytes per second. This is enough to deliver good quality, body-rocking stereo, the company says.
Read the full body-wired headphones patent application.
Researchers at MIT in Boston, US, are developing a "torch-like" device that uses sound waves to locate buried landmines from a safe distance.
The device fires a tightly-focused beam of very loud sound at the ground, causing it to vibrate. This vibration is then measured using a reflected laser beam, and the signal reveals the telltale disturbances caused by any subsurface mines.
The sound frequency employed must be low in order to shake the ground and normally this would mean focusing a beam using large parabolic reflectors. MIT researchers cunningly use a higher frequency signal, which can be focused more easily, to carry a lower frequency tone. As the focused beam hits the ground, the frequencies separate to create powerful, low frequency vibration.
The patent application reveals that MIT has already tested the system on anti-personnel mines using a sound source and a laser on a tripod positioned 30 metres away. The resulting vibrations were analysed on a laptop, which quickly produces a map of the area, highlighting hidden mines.
Read the full landmine antenna patent application.
Swiss security specialist Sicpa Holding can now add markers to high value liquids like perfume, alcohol or medicine, to prove they are genuine, but without altering their smell or taste or falling foul of health regulations.
Regulatory bodies and pressure groups have been quick to criticise previous plans to mark liquids using isotopes or antibodies. Instead, Sicpa Holding plans to uses markers that are found naturally in sea water.
Sea water contains traces of around a hundred different elements. Some of these are naturally present in commercial products, but in small quantities. So altering their concentration, by a factor of five for example, indelibly marks a product. And detection can be carried out in the laboratory, through chromatography, or with a handheld sensor, the company claims.
In tests, brandy was successfully marked with a few extra parts per million of fluoride, while whisky and aftershave were marked with additional iodide. Counterfeit copies or diluted samples should immediately show reduced marker levels.
Read the full sea water tracing patent application.
For more than 30 years, Barry Fox has trawled through the world's weird and wonderful patent applications, uncovering the most exciting, bizarre or even terrifying new ideas. Read previous Invention columns, including:
Rocket-repelling parachutes, tooth decay probe, laser healing, throwable game controllers, Microwave oven gun, Smart-card DVDs, Smart night scope, laser microphone, triple-standard DVD, ultimate body armour, Long-range stunner, tongue-o-vision, jellyfish injections, Flesh-burn sensor, fire-escape tubes, VoIP mangling, in-flight rearming, sense that fat, Designer speakers, throw-away parachutes, password-protected bullets, spinning touchdown, palmtop Feng Shui, Origami gadgets, mile-high showers, Hydrogen fuel balls, human cannonballs, the riot slimer, the bomb jammer, Apple's all-seeing screen, the TV-advert enforcer, the wing-sprouting drone, the drink-driver arm scanner, laser spark plugs, remote-controlled implants,the "I've been shot" gun, the snore zapper, the guitar phone, explosive-eating fungus, viper vision, exploding ink, the moody media player, the spy-diver killer, preventing in-flight interference, the inkjet-printer pen, sonic watermarks, the McDownload, hot-air plane, landmine arrows, soldiers obeying odours, coffee beer, wall-beating bugging, eyeball electronics, phone jolts, personal crash alarm, talking tooth, shark shocker, midnight call-foiler, burning bullets, a music lover's dream, magic wand for gamers, the phantom car, phone-bomb hijacking, shocking airport scans, old tyres to printer ink and eye-tracking displays.