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Build Your Own Bluetooth Sniper Rifle
Jim Buzbee writes "I don't think I'd do it, but these guys built a Bluetooth Sniper rifle, went to the roof of a downtown Los Angles skyscraper and pointed it at nearby buildings. See what they found, and if you're so inclined, they'll show how to build your own and maybe, just maybe, you too can snag Paris Hilton's address book." (Which was not snagged via Bluetooth snooping, as the article points out.) This version looks a bit more polished than the one mentioned last August.
Fear not. Perfectly aligned in the EM wave sense does not equal correct alignment in the mass/bullet sense. One must adjust for windage, for one thing. For another, even if you could get the range via bluetooth, the parabollic trajectory of the bullet (some calibres are 'flatter' than others, and even different manufacturers) must be taken into account based on that range.
Shouldn't that be http://www.tomsnetworking.com.nyud.net:8090/Sectio ns-article106-page2.php instead?
And from here, I can't connect..
The other
http://64.233.167.104/search?q=cache:RUM0Y5_0xhEJ: www.tomsnetworking.com/Sections-article106.php+&hl =en&client=safari
Image of the gun. Imo somebody could easily mistake that for a homebrew silencer on the end.
Your hair look like poop, Bob! - Wanker.
This article shows that "short range" RF technologies such as bluetooth or RFID are only short range in the context of a particular transceiver. If someone wants to access an RF device from a greater distance, they need only build a high-gain antenna.
Two wrongs don't make a right, but three lefts do.
Actually no.
You will hear a sonic boom anytime something travels faster than the speed of sound at your location. Typically, this means an aircraft must travel abut Mach 1.15 above you for you to hear the boom on the ground. An aircraft travelling Mach 1 will typically not produce a boom on the ground as the speed of sound is greater on the ground than it is at altitude. And, of course, anything travelling faster (i.e. Mach 4) will cause a boom as well.
Back to our program.
Not true
Mach (speed of sound) is relative to altitude.
Just to clarify, the airplane's instruments would read ~661 knots for it to be going mach 1.
Being cloer to the ground, the ground speed required to go mach 1 increases, airspeed stays the same. If you were at sealevel, and the airplane broke the sound barrier 10,000 feet above you, you'd still hear it.
Don't say at least, ecause some sniper rifles are capable of much better performance, although they are very costly. For example, the Barrett M82A1 has an MOA of 1.5-2.0 or about 4.5"-6" drift at 300 yards. Additionally, the drift depends on the angle at which the rifle is fired, even if it is aimed directly at your phone. If you're shot at from above or below there will be an additional downwards component of the bullet's velocity working with the force of gravity causing the bullet to fall faster, whereas if you are up high and shot from below there will be an upwards component of the bullet's velocity working with gravity to decrease the drift of the bullet.
just a remiander (in the absence of air resistance, and bullets are designed for minimal air resistance)
Dy = 0.5(-32 ft/s/s)(Dt)^2 + v*sin(a)(Dt)
Dt = (Dx)/(v*cos(a))
so:
Dy = 0.5(-32 ft/s/s)((Dx)/(v*cos(a)) + (Dx)tan(a)
where:
a=angle
v=inital velocity
Dt= change in time
Dx= change in horizontal position
Dy= change in vertical position
therefore, if a is between 0 and 90 degrees there will be less drift than if a is between -90 and 0 degrees.
I would hope there wouldn't being legal ramafications. You can kill someone with most things out there, but why should you be responsible for someone else's actions? We're not even talking about someone that purposefully designed a weapon for concealment and quite good ranged kills here. This is just a good antenna that some guy decided to make look like a rifle.
The shape isn't too bad since it's easy to hold and aim that way if you want it to be portable and quick to use. The problem with it is that it does look like a lethal weapon, and that makes using it dangerous. Would've been a better idea to set it up like a telescope on a tripod. Then you still get good portability, but a more stable base.
It may be irresponsible to build a device intended to get you surreptitious access to others people's mistakely considered private data, but no more than that. Perhaps he'll catch some hell for designing an electronic surveillance/eavesdropping device, but I would hope not.
Someone would have to go through some lenghts to make that fatal, too. You would definitely have to pump out a *lot* more power. You'd need a fair bit more than 115VAC@20A(=2300W, 2000W radiant) to saturate a target to lethal exposure at 200m. Your components would all have to be replaced to handle the higher power. You could screw up someone's eyes quick, maybe their bladder over a little time, mess with some guys testes, etc., without much trouble, but near term death isn't likely.
Then again, anybody that can get their hands on a Magnetron can build a more dangerous version of this. Step one: buy a microwave oven. Step two: take it apart for the Magnetron.
Bah, go study up on exterior balistics my friend. Gravity, acting on the bullet is straight down, but if the bullet isn't traveling perfectly horizontal, then the gravity vector of 32 feet per second per second isn't being applied at right angles to the path, but at a vector.
.707 in round terms, making the true horizontal distance traveled only 212 yards, so the fall is proportionatly reduced and the bullet will hit a wee bit higher than the 300 yards over level ground math would indicate. Just a very few inches at 300 yards depending on just how far your piece can reach out and touch someone, but a much larger difference will be seen at the longer ranges and at even higher angles from level.
So if you are shooting downhill at a 45 degree angle, then that 300 yards you mentioned must be multiplied by the sin of the downward (or upward, they are in fact interchangeable) angle which for 45 degrees is
There are other effects to figure in, such as the distance for the air to slow it down remains at the line of site measured distance of 300 yards so the loss of velocity remains at the 300 yard figure. So does the effect of a crosswind in the drift.
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Cheers, Gene