Drone Meet DroneShield

From Voice of Russia:

DroneShield warns of low-flying UAVs with 18 nations demanding the device - inventor

Photo: EPA

In a matter of a few years, tons of drones could be whizzing around residential zones, taking away tiny pieces of privacy people once had. DroneShield is a fresh new concept that alerts of nearby low-flying UAV devices in the area. John Franklin, one of the developers, told the Voice of Russia that 18 countries, including Russia, have already put in orders for the gadget and has been creating buzz ever since.

Less than seven years from now there be up to 10,000 privately owned and operated drones gliding through the air in the US alone, according to the Federal Aviation Administration’s forecast. Though, the most recent device on the market promises to alert residents of when a small-sized drone has dropped by to visit.

DroneShield is an idea that has been brought to life thanks to crowd-funded resources and the designer of the device aerospace engineer John Franklin along with co-inventor Brian Hearing. The uniqueness in the $99 device is due to the super sensitive microphone it uses to pick up on a drone’s acoustic signature. It then takes in the sound data and it undergoes processing with a cheaply made, mini Raspberry Pi computer. 

Afterward, the shield device clarifies what the noise is by selecting from an internal list of drone sounds.

One incident sparked Franklin to create such a tool to empower the public during a test drive of his own drone he had purchased in a store. The very first time he used his unmanned device was to scope out debris or pool water that might have been collecting on the rooftop of his row house. Instead, it crashed into his neighbors’ yard. Although Franklin saw it as a nifty looking toy, the expression on his neighbor’s face left a different kind of impression.

"My neighbors’ reaction changed my perspective totally," Franklin said to the Voice of Russia and then went on, "For them, the drone represented the disembodied eyes of a stranger." That very experience ignited a fuse in the aerospace engineer and motivated him into launching up a drone campaign with Heading, the other co-founder of the company, with the campaign via Indiegogo. It seems to be a success story in the making....MORE

We've had a couple posts on the Rasberry Pi single board computer: 

What Are People Doing With the Raspberry Pi Computer? Wired UK on Sale May 30

UPDATED--"Build your own supercomputer out of Raspberry Pi boards"

The writer of the DroneShield piece is a bit effusive with "The uniqueness...".

In mid-World War I, i.e. pre-radar, Britain's Royal Engineers were trying to figure out how to detect the terror weapon of the day, The Zeppelin, at a distance. They came up with what they called Acoustical Mirrors which gathered the sound of the Zeppelin's motors and concentrated it on a spot where a trumpet shaped microphone was placed:

 4.5 metre high WW1 concrete acoustic mirror near Kilnsea Grange, East Yorkshire, UK. 

The pipe which held the 'collector head' (microphone) can be seen in front of the structure

A minder would hear the sound of the gasbags approaching and telephone a warning.

Here's the one at Redcar via Andrew Grantham's Sound Mirrors blog:

The sound mirror at Redcar on the Yorkshire coast was built in about 1916, during the First World War.
These pictures were taken in December 2002. Click on a picture to see a bigger version.

The mirror at redcar has a modern plaque explaining what it is. The base for the listening apparatus has survived, about four feet in front of the main structure.

The mirror is now surrounded by a modern housing estate.

A close up of the plaque. This reads:

REDCAR EARLY WARNING STATION

This structure is a Sound Mirror or detector, built by the Royal Engineers in 1916. It was part of an extensive Zeppelin and enemy aircraft detection system deployed down the East Coast of Britain druring the First World War. Zeppelins raided the North East Coast 15 times between April 1915 and November 1917.
The sound of approaching aircraft was reflected off the concave ‘mirror’ surface and received into a trumpet mounted on a steel column.
The trumpet was connected to a stethoscope used by the operator or ‘listener’, and the part of the dish that produced the most sound indicated the direction of the approaching aircraft. Advanced warning of an imminent attack could then be given to local people.
By the early 1940′s sound detection technology was being replaced by ‘reflective detection finding’ now known as radar.