Theremin Proximity Fuze?

[nbk2000]

Browsing around the internet, I ran across an obscure musical instrument called a 'Theremin', which produces varying tones depending on the location of the operators hands near field-capacitance antennas.

Now that's very similar to what proximity fuzes use, a capacitance field is created and changes in that field trigger the weapon to fire.

In it's simplest form, the theremin is a couple of IC's, and some resistors and capacitors attached to an antenna (see attached diagram).

I don't know the range, but that's proportional to antenna size and distance.

The PDM shoots out wires 15 feet in each direction and explodes when they are disturbed.

I'm thinking that the wires of a PDM could be acting as antenna's, with the body acting as a ground (or vice-versa), with a simple low-power theremin-like circuit acting as an e-field generator.

A website where the e-field is being used as machine vision for robots:
http://thereminvision.com/

A supplier for an e-field kit, for $50:
http://www.robotlandinc.com/tvision.htm

[atlas#11]

That seems ridiculusly simple for something that would be so effective. The devices generate a field around them, so they could be detected. But it would take a hell of a lot of deaths to convince all the pigs to carry a theremin detector.

Obviously there would have to be some sort of timing circut to allow you to get the hell out of the area before it is armed. And you would have to set a pretty high threshold on the frequency changes. A change in humidity could effect it enough to trigger the bomb, or even a mouse crawling inside the walls. I would be nervous as hell settings one of these, then again, I'm always nervous.

It would definatly impeed a search if the bomb sniffing dogs got blown up every time they got close. It would take the labs a while to figure out how the hell the bombs were being set off, since all they have to work with is a couple melted fragments of an IC. I think the antenna would be the biggest give away, use a piece of magnet wire or something obscure like that mabye. I definatly like this idea, but I would hate to be anywhere around any of them when their armed.

[Jacks Complete]

If you think they might be using a theremin/e-field detector (which would be jammed quite neatly without trouble if you used a more passive aerial and used a local radio station or background mains hum for the power source) switch to a PIR for a change.

In fact, if you want rid of the dogs, line up a PIR with a rifle so that it shoots anything hot that appears in the right place. Then set the Thermin to detect a human that is upright. And, of course, the robot they send in won't be hot or tall enough, and will have a signature totally unlike a human. So it won't find anything, especially the charges papered over in the walls at head height.