Techno News: flight

Pocket-size drone that can fold up

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<tr><td class="tr-caption" style="text-align: center;">Pocket-size drone that can fold up</td></tr>
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Researchers have designed a small, foldable drone,<br />
inspired by origami, which can unfold itself automatically<br />
and take flight within a fraction of a second.<br />
A large number of these quadcopters, the size of an outstretched palm, could be released over a disaster zone to take photographs and make contact with survivors.<br />
When the device is not in use, the arms, which are made of fibre glass and light, yet rigid polyester, fold up into a trapezoid. When switched on, force of the propellers causes the arms to unfold horizontally. Then,<br />
magnets keep the arms locked into position.<br />
For the drone to remain stable during flight, two<br />
propellers (diagonally across from each other) spin in<br />
opposite directions from the other two. Propellers all spin<br />
in the same direction at first while the drone unfolds, but<br />
a sensor detects when the arms have locked into position,<br />
and within 50 milliseconds, direction of two of the rotors<br />
is reversed, and the drone is ready to take flight.