previous post next post  

A Head Scratcher

 I knew the military had this technology, and presumably it is available the LEOs as well, but...

This scenario (from the link above) is kinda curious:
You are walking down the street with a friend. A shot is fired. The two of you duck behind the nearest cover and you pull out your smartphone. A map of the neighborhood pops up on its screen with a large red arrow pointing in the direction the shot came from.  


14 Comments

The best known military capability is called Boomerang.  It uses an array of microphones and a complex algoritim to detect the source of bullets, accounting for echoes from buildings, etc. How you can do that with a single microphone is beyond my limited understanding of the physics.

 
 I would think it's nigh impossible with a single phone, but with two or more the complexity of the problem drops dramatically. An array of localized phones is no different than Boomerang's array of discrete microphones.  It's a little funny that the Armorer posted this as just this past weekend I was dinking around under the hood of my android phone playing with the accelerometer and magnetic field sensors and discovered that my phone (and most androids) have an acoustic sensor which can provide audio level data...the gunfire detection concept was the very first thing that leapt to my mind.
 
 The problem is one of echoes, and of atmospheric conditions that might relay the sound without it being attenuated over distance.

When you introduce all those variables into your equations on which to base your app, this system will any more accurate than your basic brain connected to your basic ears.
 
 Should have read "will NEVER be any more accurate"
 
...and *Zero* posted it, not me.
 
 Ugh, basic literacy fail on my part...again. Definitely a Monday.
 
"Omnidirectional microphone" 
 
From the article:
"Like the military version, the smartphone system needs several
nodes in order to pinpoint a shooter’s location. As a result, it is
best suited for security teams or similar groups."
  So, just one phone would leave ya hanging. Wonder how that
system would handle a supressed weapon, with the shooter
aiming to pass the bullet close to a strucure that would effectively
echo the shockwave as a muzzel report?

 
PrimEvil: I was interested in the same sort of thing. Forget suppressed

Why would an unarmed civilian do more than hunker down?

"Oh Goody, my phone tells me the shot came from over there." And then share it on FB



 
Lessee, how could we defeat this?  The first think which comes to mind is those captive-piston pistols we used in the tunnels in Viet-Nam, and also some of those Spetsnaz weapons.  Really big air rifles shooting very heavy low-velocity bullets might work. The latter was used in a Sherlock Holmes story.

Y'all may have noticed that my first reaction to this was about how to defeat it.  I REALLY dislike those statist busybody puritan mommy monkey people who make it their life's work to mind other peoples' business.
 
P.s.  Crossbows.
 
P.p.s.  Crossbows with poison warheads.  I could walk about a mile from here and buy some poison arrow frogs at the exotic "pet" shop.  Not having the money for that, there is always nicotine sulfate.
 
JTG,
What a futuristic idea, www.topairgun.com/girandoni but I think someone beat you to it, and not in some detective novel.
 
P.p.p.s. As it happens, I have a coupla dozen rosary peas in my pocket at this very moment. I picked 'em up off the ground because they are purty. Honest. They grow wild around here. Also, we have oleanders. Flarduh has LOTS of toxic plants.