- Source: New Scienist
12:11 02 October 2006
NewScientist.com news service
Can a surveillance drone be made virtually invisible? VeraTech,
based in Minnesota, US, thinks so. And patent applications filed
by the company explain how.
"Persistence of vision" turns the fast-moving rotors of any
helicopter into a near-transparent blur, while the slow-moving
body looks solid. Inventor Michael Dammar has come up with a way
of making the whole body of an aircraft spin as it flies, turning
it into a single blur in the sky. This would not evade radar but
should help the aircraft avoid visual identification.
The so-called Phantom Sentinel aircraft is Y-shaped, consisting
of a single long wing attached to two short aerodynamic
extensions which each end in a propeller. And the weight is
carefully balanced so that the centre of mass is positioned
between the two extensions. When the motors are running, the
solid part of the aircraft spins around this centre of mass, and
the longer wing generates lift. The whole thing moves so fast
that persistence of vision turns it into a single blur.
Making the plane sky blue, or largely transparent, should help
conceal it further, Dammar claims. He adds that a camera can be
placed near the centre of mass and used to build a panoramic
picture of the ground below, after software processing.
The companys website has streaming video footage of early
prototypes in flight.
Read the full invisible drone patent application.
The idea of wearable computing is appealing. A head-mounted
display can show information processed by a small portable
computer while speech-recognition software can replace keyboard
typing. But how do you move a cursor without a holding a mouse?
Simply move those feet, say three researchers working for Hewlett
Packard in the UK. A magnetic sensor can be attached to one foot
and a transmitter emitting pulsed magnetic signals clipped onto
the other one. As the sensor foot is moved around it continually
calculates its position relative to the other foot, using these
So, moving each foot can correspond to movements of a cursor on
the head-mounted display. Foot-twisting can be used for right or
left mouse clicks and sliding one foot over the ground can be
translated into dragging and dropping. This would allow someone
to use a wearable computer while keeping their hands free for
Read the full hot-foot computing patent application.
Threading a cable through the chassis of a car, boat or plane can
be tricky. Sharp metal edges can cut the cable insulation,
shorting power and even starting a fire.
Researchers at the University of Vermont, US, have been working
with NASA on a type of cable insulation that heals itself when
breached. The healed section also adds a protective layer against
further damage in future.
The central live wire within the cable is surrounded by a layer
of insulation laced with a soft resin. Glue hardener is also
sealed inside microcapsules that are dispersed within the
Under normal circumstances the microcapsules keep the hardener
away from the resin, so the cable remains soft and easy to
thread. But if the cable insulation is chafed or breached, the
microcapsules break open to release the hardener. This heals the
insulation and adds a solid section that should prevent further