DroneShield: alerts you to nearby drones

<img src="http://shop.droneshield.org/media/title_new.jpg" align="center" width="700">
From http://www.droneshield.org/technology/:

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DroneShield is a low-cost, easy-to-use device that detects the presence of nearby drones (including RC helicopters, quadrotors, etc) and issues alerts via email, sms, and a flashing light. The goal is to help preserve privacy from low-cost remote-control air vehicles with video cameras.
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Among the uses cited for users of this product are "Warn VIPs to paparazzi or other unauthorized pursuers," "Warn sportsmen of activist groups," "Protect farmers and producers from animal rights and environmental activitsts," "Protect outdoor venues from illegal recordings and broadcasts."

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