cda@utai.UUCP (11/12/87)
Okay, now I'm REALLY mad and I'm gonna do something
(nasty) about it. I have, once again, been stuck on
a long train ride near a person who was blasting
their walkman to the extent that is was disturbing
other passengers. As is often the case, complaints
had little/no effect.
I'd like to build a walkman jamming device for
use on the train. One for walkman radios would be
easy, but of little use. Any ideas whether a
short-range tape-recorder jammer (i.e. noise
generator) is feasible? Any suggestions for
such a circuit are welcome.
(Please don't bother telling me about telling
a conductor, I know it's possible although it doesn't
work well. I also know I could just wear my own
load walkman, but this solution is much more
satisfying).wolfgang@mgm.mit.edu (Wolfgang Rupprecht) (11/13/87)
In article <4149@utai.UUCP> cda@utai.UUCP (processor) writes: > I'd like to build a walkman jamming device for >use on the train. One for walkman radios would be >easy, but of little use. Any ideas whether a >short-range tape-recorder jammer (i.e. noise >generator) is feasible? Any suggestions for >such a circuit are welcome. Sounds like a few surplus SDI giga-joule capacitors and a few loops of wire will do the trick. Problem is you and the jammer will hardly fit in the subway car by yourselves. You won't have to worry about some urchin coming along blasting a tape deck in your ear. Oh yes, you will have to watch out for pace-makers too. Not really desirable to shut grandpa down in the attempt to quiet a tapedeck. Now for a fun kinetic energy weapon design. I built a few of them back in highschool. Take all the large 200v capacitors you can find and tie them all together in parallel. The more, the better, at least a few 100 uF's are needed to do anything. Tv power supplies are a good source for these. Add a charging circuit (a bridge from an isoloted 120 vac with a several watt ceramic 100ohm series resistor is cool). Find a plastic tube, 6" long with a 1/4" bore. Mount a coil of several hundred turns on the plastic tube. drill a small hole ~1/2" below the coil, and insert a small plastic piece to act as a support. Leave plenty of room for air to rush around this support. Now drop a ferrous object down the tube, and energize the coil. I used a spdt push-button switch which would alternately charge the caps via the resistor, and discharge them via the coil. If you have a strobe you can probably adjust the timing such that the field collapses just as the launched object passes the coil. Now if you build this: PLEASE BE CAREFUL, 200v can KILL YOU. The launcher on the other hand is relatively safe, it probably won't do more than give you a bruise, unless you are looking into the barrel as it fires, etc. (At least mine never had much umph. Even though I experimented with various L/C/wire-guage/coil-to-object-spacing combinations.) Oh, I should also mention. The caps aren't really designed for this sort of abuse (no kidding wolfgang!). The plates will fatigue from the combined forces induced by a rapidly dropping e-field and a quickly rising m-field. You will hear a distict <click> as the plates move during "launch". What gets really exciting is when one of them finally shorts out. Hint: Don't leave out the charging resistor. You can also add a 1-amp slow blow fuse. Be warned. Wolfgang Rupprecht UUCP: mit-eddie!mgm.mit.edu!wolfgang (or) mirror!mit-mgm!wolfgang ARPA: wolfgang@mgm.mit.edu (IP addr 18.82.0.114)
ralph@ncrcae.Columbia.NCR.COM (Ralph Hightower) (11/14/87)
Why don't you use the Vulcan nerve pinch like Spock did to that guy with
the "ghetto buster" on "Star Trek IV-The Voyage Home"?
--
ralph@ncrcae.Columbia.NCR.COM <Ralph M. Hightower>
NCR Corp., Engineering & Manufacturing - Columbia, SC
Home of THE USC! (Oldest Public Funded University in USA)
South Carolina had a University 49 years before California was a state Druslan@ecsvax.UUCP (Robin C. LaPasha) (11/14/87)
In article <4149@utai.UUCP>, cda@utai.UUCP (processor) writes: > Okay, now I'm REALLY mad and I'm gonna do something > (nasty) about it. I have, once again, been stuck on > a long train ride near a person who was blasting > their walkman to the extent that is was disturbing > other passengers. As is often the case, complaints > had little/no effect. > I'd like to build a walkman jamming device for > use on the train. One for walkman radios would be > easy, but of little use. Any ideas whether a > short-range tape-recorder jammer (i.e. noise > generator) is feasible? Any suggestions for > such a circuit are welcome. Well, the other stuff sounds fascinating (kinetic energy weapons, Vulcan nerve pinches,) but wouldn't a close approach of a magnet mess up the guy's tape as well? Maybe it would have to be as big as the Edmund Scientific half-pounder (just to make sure) but it'd be simple. On the other hand, you still have to worry about pacemakers (they adjust with magnetic gadgets of some sort) and your own nearby diskettes (!) and any metal-detection or theft-proofing (likely including library) passageways you have to go through. You'd also have to get close to the dude and put your magnet near or on his deck. Would he be able to figure it out? How fast can you move if he can? Cheers. Robin LaPasha ruslan@ecsvax.UUCP
lyndon@ncc.UUCP (Lyndon Nerenberg) (11/16/87)
> Well, the other stuff sounds fascinating (kinetic energy weapons, > Vulcan nerve pinches,) but wouldn't a close approach of a magnet > mess up the guy's tape as well? Maybe it would have to be as big > as the Edmund Scientific half-pounder (just to make sure) but it'd > be simple. > > On the other hand, you still have to worry about pacemakers (they > adjust with magnetic gadgets of some sort) and your own nearby > diskettes (!) and any metal-detection or theft-proofing (likely > including library) passageways you have to go through. Do this and you can kiss your mag strip bank cards goodbye too...
tomb@hplsla.UUCP (11/17/87)
Re: Jamming mobile tape players -- Since the tape head is a magnetic-field transducer, it seems to me that you MIGHT be able to mess one up if you generate an AC magnetic field. This could take the form of a large coil hidden away in a briefcase or some such, driven by some appropriate noise generator. Since noise is in the ear of the beholder, you might even try some music you like -- but I suspect that you will have more success if you use a waveform with a fairly high RMS-to-peak ratio -- or maybe one which transmits occasional intense random bursts. I just tried this sort of thing with 60Hz coil about 3 cm in diameter, and wasn't too impressed with how close I had to put it to the tape player to make it really objectional (the tape heads are shielded, after all). I'm sure, though, that I could do better with some experimentation and calculation: expect larger coils and higher frequencies to help a lot. The above method has the advantage that it doesn't erase the tape, which could get you into more serious trouble after your initial joy wore off and the dude whose tape you erased figured out what had happened. Happy experimenting! Tom Bruhns uucp: !hplabs!hplsla!tomb
acm@bu-cs.BU.EDU (ACM) (11/18/87)
In article <4149@utai.UUCP> cda@utai.UUCP (processor) writes: > I'd like to build a walkman jamming device for >use on the train. One for walkman radios would be >easy, but of little use. Any ideas whether a >short-range tape-recorder jammer (i.e. noise >generator) is feasible? Any suggestions for >such a circuit are welcome. I don't have a circuit here, sorry, but here's some observations. The scanners that many stores use seem to be very effective at creating noise; creation of a similar, although probably less powerful, circuit might work fine. Many expensive walkmans are shielded, however. The one that I used all the time (Sony Walkman, the first of the "real thin" series but far into the walkman revolution) wasn't in the least bothered by the scanners. Most of my friends' walkmans were. You might note that I was using Sony MDR20 headphones, not the real cheap ones that came with the walkmen -- it seems likely that the headphones could be picking up the signal, not the walkmans. Good luck on your circuit. I've been similarly annoyed on long bus rides between school and home. jim frost madd@bucsb.bu.edu
robert@uop.EDU (/dev/null) (11/20/87)
lets see, a cattle prod would maybe put out enough spark to kill the micro chips.. sissors to cut the wire....... a large magnet to erase their tapes.... an emp spike strong enough to waste their ears and headphones... oh yeah, and dmso mixed with lsd brushed onto the tape case... or a .38 with a silencer... cobra venom in the pepsi spark plug in their gas tank filler plug (drain and keep most of the gas) yes you hook it to the coil!
dce@starfish.Convergent.COM (Dan Eykholt) (11/20/87)
In article <4149@utai.UUCP>, cda@utai.UUCP (processor) writes: > Okay, now I'm REALLY mad and I'm gonna do something > (nasty) about it. I have, once again, been stuck on > a long train ride near a person who was blasting > their walkman ... > I'd like to build a walkman jamming device for > use on the train. Just purchase the "BOOM BOX JAMMER" TM from your local connivance store. Actualy it's just a simple 9 pound hammer. Just distract your victim a little, then tap the box with 50gs or less, thus causing the tape/CD to jam. If you can not find this, pruchase a can of polyuerthane (sp) foam and seal the leaks. No I have never used this techique. The .45 works better. Oh, of course you could just ask the offensive one to lower the volume.
cs211s40@uhccux.UUCP (Taro Nobusawa) (11/23/87)
~~~~~~
I don't know if this is such a good idea. It seems to involve more risk
then benifits. As was pointed out, such things can be unhealthy for
pacemakers, disks, bank cards, etc... Someone else menthioned the
security systems used in stores, libraries (our campus uses them) that
involve having the books, mechandise tagged w/a small foil strip.
The sensing mech. seems to produce noise on walkmans but doesn't
harm diskettes, cassette tapes, etc. (although at the library, they
have a notice warning not to take mag. media through & I have had
a person I know have a floppy disk zapped) My Sony D-10 CD player
seems to set these systems off if it's on. Even using this system
may be impractical to get into a managable size.
--
"Butterflies if you throw it hard enough" -some book title
Taro Nobusawa cs211s40@uhccux.BITNET
cs211s40@uhccux.uhcc.hawaii.edu
Compu$erve: 71071,322rees@apollo.UUCP (11/24/87)
I'd like to build a walkman jamming device for
use on the train.
I would never have believed that a walkman could produce enough sound
to even be heard, much less be objectionable, over the background noise
on a train if I hadn't seen exactly this thing myself. Imagine how loud
this must be to the person with the earphones on!
If I wanted to build such a device, I would try transmitting a signal
on about 50KHz or so. At this frequency you have a reasonable chance
of getting a significant amount of energy coupled into the play head
on the walkman. The theory is that this would intermodulate with the
bias signal on the tape and produce audible noise. For maximum effect
the signal should be approx. 1 KHz or so off from the bias frequency,
and frequency modulated with the noise source of your choosing.
I would start with an audio amp chip, the kind used in car stereo
applications. Get one with external equalization so you can run it
above normal audio frequencies. You should be able to get a couple
of watts out of it. For best results you'll need a honking big
coil to act as an antenna (either that or a couple hundred feet of
wire, hard to hide on a crowded train).
I have no idea whether you could couple enough energy into the play
head at reasonable range, or whether there is even enough residual
bias voltage on the play head to get the desired intermod products.
The play head and associated electronics will be designed to reduce
the residual bias, so it will be an uphill battle. Maybe Larry Lippman
could grace us with some of his elegant calculations, or suggest a
better method?cgs@umd5.umd.edu (Chris Sylvain) (11/24/87)
In article <38a77098.b8ab@apollo.uucp> rees@apollo.uucp (Jim Rees) writes:
< [...] For best results you'll need a honking big
<coil to act as an antenna (either that or a couple hundred feet of
<wire, hard to hide on a crowded train).
Build your antenna coil into a cane or umbrella, and mutter incantations
as you point it at the offending walkman for effect.--
--==---==---==--
.. the Jabberwock, with eyes of flame, ..
ARPA: cgs@umd5.UMD.EDU BITNET: cgs%umd5@umd2
UUCP: ..!uunet!umd5.umd.edu!cgscopp@wind.UUCP (11/24/87)
A friend once contemplated building a machine to jam supermarket music systems. Many of the markets in our area buy their music from an FM station--a subcarrier system--and it appeared to be fairly simple to put a low-power FM transmitter in a briefcase and capture the receiver.
ajg@whuts.UUCP (GAETA) (11/24/87)
My mother-in-law yelling would make an excellent jamming device.
larry@kitty.UUCP (Larry Lippman) (11/25/87)
In article <3810@bellcore.bellcore.com>, copp@wind.bellcore.com (*David H. Copp) writes: > A friend once contemplated building a machine to jam supermarket > music systems. Many of the markets in our area buy their music > from an FM station--a subcarrier system--and it appeared to be > fairly simple to put a low-power FM transmitter in a briefcase and > capture the receiver. Damn! I wish I had thought of that while I was a carefree EE undergrad. It would have been easier to implement that the following escapade of my college daze... During my junior year, my roommate (also EE) and I came up with a great (!) idea: to jam the audio at a drive-in movie and insert our own "commentary". This project required weeks of, ahem, preparation. First, we scrounged an old Bogen 100 watt PA amplifier of 1950's vintage, and modified it to run using an external DC power supply - which consisted of a WW II surplus dynamotor. Since the dynamotor required 24 volts DC, we made a temporary installation of two 12 volt batteries in the trunk of my car. The dynamotor also went in the trunk, with a remote control switch. The amplifier sat on the rear seat, and was covered with a blanket. Some "preliminary investigation" at the target drive-in indicated that a 70 volt line transformer was mounted in the base of each speaker pedestal, and the one transformer fed two speakers. We decided to back-feed into the system at 70 volts. On the fateful night, my roommate and I along with two carloads of "supporters" invaded the drive-in. We parked in the last row. Under cover of darkness, I removed the cover plate at the base of our speaker pedestal, and attached two 22 AWG magnet wires to the 70 volt feed. There was enough clearance on the cover plate to allow the magnet wires to pass when the plate was put back. Also, the magnet wires allowed for a rapid - and hopefully inconspicuous - breakaway. I don't remember the name of the movie, but it was a low-budget horror film about witches in England. The movie was ripe for a "commentary". With all connections made, I turned on the dynamotor. After the tubes warmed up, I cautiously advanced the master gain control. Voila! Feedback, even though our own speaker was turned off. It worked so well, that we had to close all windows in the car. My roommate and I engaged in a running "commentary" [y'all can use your imagination here :-)]. The people at drive in went wild - blowing their car horns in delight. The management went nuts. After about five minutes, two people ran out of the projection booth with flashlights and started checking cars. Needless to say, it was time to pull the plug. The fellow who came over to my car looked at us with great suspicion, since we and the two adjacent "support" cars were all laughing hysterically. However, no one said anything to us - I think the drive-in management was still in a state of shock that someone could do such a thing... Since many drive-ins today use an inductive loop AM radio approach, perhaps this would be easier to do using an AM transmitter (easy to make using the power op amps available these days). Of course, such a transmitter would be unlawful to use, and I could never condone such a thing for a prank... :-) <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|utzoo|uunet}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
max@zion.Berkeley.EDU.UUCP (11/26/87)
This does not equal Larry's anecdote but it does give you a true example of the effective deployment of electronic countermeasures by civilians against obnoxious FM radio reception. I have a friend, whom I will call Joe, who a few years ago was a quiet electronics technician of the old school. Although too young to properly qualify as an old fart, he liked to build things with vacuum tubes. Joe is also a cellist, and a member of a large local family. He likes to practice his cello, or play the organ, for relaxation. Anyway, at the time of this anecdote, Joe had moved into an apartment in Oakland, California. He did not play the cello or organ there, out of respect for his neighbors (nowadays he owns a house, and besides, his neighbors like the music). However, in the apartment building were some Very Noisy People. They would play FM stations at all hours, loud. They acknowledged but did not act on requests to moderate the volume. Now hereabouts this sort of behavior is illegal -- the police call it a 647 violation, Disturbing The Peace, so Joe could easily have complained to the police. But his style was much quieter, and subtler, than that. He built an FM jammer, which came in later years to be passed around a lot and dubbed "the family FM jammer." (This was very much in character -- Joe was always building clever gadgets to fill a need. The family is very handy with things like that, making do -- Joe's parents grew up, of course, in the Depression.) It was a beautiful piece of work: built on a block of wood, with open-air coils, a large glowing VHF tube, and porcelain insulators. It would have been completely at home in a 1930's sci-fi movie with Bela Lugosi in a starched white smock that buttoned up on one side. The jammer used, simply enough, the 60-Hertz power line to frequency-modulate the carrier. With characteristic attention to detail, Joe had made sure that the modulation was just enough to cover the desired channel without spilling over to adjacent ones. Yes, it was assembled and aligned with all the loving care of a commercial transmitter expecting outside inspection. The procedure was simple but delightful. When the Noisy Neighbors decided to play loud FM, and this got to bothering Joe, he would warm up the jammer. Because the jammer needed precise tuning, and also because the problem had now become a sport, Joe worked the tuning dial with the fingers of a safecracker, and all the patience in the world -- I like to think, though I don't really know, that he had a cigar and a glass of port, perhaps Graham's Malvedos 1955. Presently a horrific buzz would replace the (inevitably pounding) dance beat audible through the wall, provoking vaguely audible expletives of discontent. Someone would change the station, and the music would return. It didn't bother Joe; he was patient, and he was sure of his quarry. Eventually he would find the new station and they would change it again. Sooner or later there were expletives of resignation and the receiver was turned off. To his fortune, they rarely played anything but FM (AM, of course, would have been even more manageable, but records would have required a radically different approach). All of this had the effect of translating a nuisance into good clean sport, at least for a patient cellist like Joe. Naturally, as a law-abiding citizen, not to mention a commercial licensiate of the FCC and bound by the statutes of the Communications Act of 1934 as amended, I would have been horrified and obliged to report this behavior had I not learned of it well after the fact.
robert@uop.EDU ( ) (11/27/87)
there is a guy in one of the fraternity houses here that built a "black box" transmitter, it had an on switch and a VCO, he would tune the little bugger around the FM band and run to full quieting his neighbor's stereo.. this was great, since it did not hurt the stereo at all! and it was a pocket sized gadget.. the other thing to note, is a CB that runs a little high on the out- put side (that is your buisness not mine) will often times put out enough RF to modulate a speaker. we had a band amp go nuts with a guy about a block away from our rehearsal area, everyone standing around discussing the next gig, when "Yeah Goldduster, thats a 10-4" comes blasting out of one of our amps.. i guess he just was putting out enough to excite the plate in the tube section, and it amplified the differences it had.. also i noticed when i was a kid (you were a kid?) that when i tuned my radio shack aircraft reciever (the one that you put together with spring clips) that it is so unsheilded that it will put nice black and white bars across your T.V. screen! just tune it around until it happens and then label the dial for "channel 10" or whatever, this was great, as it took my sister a couple of days to figure out how it was that whenever she wanted to watch something, the reception went crazy! oh well...
wtm@neoucom.UUCP (Bill Mayhew) (11/29/87)
<< Larry's Drive-in confession >> I can't come close to being as inventive as Larry and the truly monumental drive-in prank, but it did remind me of being a devious prankster in highshcool and college. My favorite prank was rigging lockers in highschool. My friends and I would cruise the streets on trash pick-up day looking for old TVs and radios. We'd grab the speakers to make oscillators for lockers. One time I wrapped up the 8 D-cells for the oscillaotr in brown shopping bag paper. When the janitor found it (naturally the guilty return to the scene of the crime to gloat over their exploits) he saw the blown tubualr battery packs and thought it was a bomb. I don't know how he and the principal missed me, as I was sitting on the steps about 20 feet away colapsed in laughter. The best locker device was an old truck horn that a friend picked up at a garage sale. About a dozen kids got together and descended in several waves on all the local Radio Shack stores to get 96 D-cells with our free battery-of-the-month cards. The trigger device was a little 12 volt crystal-can relay held open by an almost dead Radio Shack 9 volt battery. When the battery went dead, we planned, the contacts of the relay would be sacrificially welded together and activate the horn at deafening volume. We warned the planter not to test the trigger, as it was planned to be sacrificial. We became suspicious, when after 1/2 hour there was no blaring horn audible. The planter admitted to having tested the trigger. We conned the planter to go out and kick the locker in hopes that it would jar the horn to life, as resitution for violating our orders. When he kicked the locker, the relay crippled by tre previous test, set the horn off sounding like a half dead cow. Somehow, we got away with it, eventhough it should have been obvious to the teachers that we were guilty. I think that the teachers were secretly amused too. I got my "bomb" oscillator back by stealing it back from the physics teacher's classroom, where it had been sent by the principal for "analysis". I was much less inventive in college. Actually I had some grandiose plans, but never got the time between studying to implement them. The best prank there was a time delay device built with a 555 timer and a couple of 7493 and a 7400. I set it up so that after 1/2 hour, the last 7493 wold set a latch and energize a reed realy to turn on a motor run by a D cell. The motor as directly attacted to a thread spool on the motor shaft. The motor supplied just enough torque to overcome the friction supplied by a paperclip and allow gravity to take over and unwind several feet of thread from the spool. A giant squishy plastic tarantula purchased at a Spencer Gifts was attached to the thread. The whole contraption was concealed in a small box that had originally been the shipping carton for a Triad interstage audio transformer. The device was small enough to sit on top of a pull-down movie screen in the front of the Electromagnetic Fields Theory I class room. One day, about half way through a particularly uninteresting lecture, the spider made its descent. What was fun was that the prank device was clearly visible to the class before the descent, but not the instructor. Fortunately, the general laughter that erupted saved the truly guilty party (me) from being nabbed. Bill Mayhew NEOUCOM (wtm@neoucom.UUCP)
robert@uop.edu (Hi how ya doin) (12/24/87)
In article <313@sas.UUCP>, jcz@sas.UUCP (John Carl Zeigler) writes: > Then there is all those things you can doo with nitric acid. . . Oh, you mean the "Lightbulb joke" ?? > Pyromania ? me???? no way!!! me either!!