If you want my advice, set up an IRC server and teach people how to use it. It should be exceedingly easy for you to track all of it's usage. True it might not exactly facilitate people communicating to/from off-campus but it would solve your accountability problem. You could even use Trillian as the client, thus giving people that "IM feel".
Before our campus moved to a fully switched LAN, I used to use Ethereal to sniff my whole dorm's AIM traffic in real time. 80 people, not that much traffic. Even in the evening at peak utilization it was easy to keep up with, no worse than a busy IRC channel. So IMO AIM is not a bandwidth hog.
The protocol itself is not as efficient as it COULD be. I did notice occasional repeated messages, and signon/signoff messages are repeated frequently. But we're still talking about piffiling small bandwidth.
PS I'm just kidding and I didn't actually do anything that I've described in this post. By reading this post you agree that I didn't run a sniffer, or reverse engineer AIM's protocol just by watching it's traffic in a sniffer.
Now just a sec, I LOVED my databank watch! I kept all my BBS numbers in there!
For speaker/mic purposes, use a little earbud headset like a Jabra. Handsfree. They rule. Period. Why does a phone have to look like a phone anyway? Why do you have to hold it to your ear? Bluetooth headsets! Lets get out of the 20th century.
I guess the pocket PC form factor isn't the greatest for gaming, although with the touchscreen... Nevermind, I hate getting fingerprints all over my screen. It could be improved, anyway.
Okay I will admit that one size does not always fit all. But I would still kill to compress my ham radio, AX.25 TNC, pocket pc, and gps receiver into a single unit. APRS baby!
Thats right, they all have a microprocessor, some buttons, and an LCD, and take batteries! Whats the real difference between an iPod and a pocket PC with a big microdrive? Not a lot.
And furthermore, what do all of THESE devices have in common?
Cell phone
GPS receiver
Ham radio
2 way text pager
FM radio
Scanner
CB radio
Thats right, they have ALL of the same traits as the aforementioned devices, with the addition of an RF DSP chip. Again, a lot of overlap
So whats my point? Sure you could carry one of each of these devices, but do you have enough pocket room? Or room on your belt? Do you want to fuck around with all those batteries and no convenient way to interface the devices to each other? You COULD merge all of these devices into one single SUPER DEVICE.
Sound crazy? It's not. A PocketPC already can do most of this stuff. MP3s (DiVx to boot), games, PIM, whatever other software you want. They've already squeezed cell phones into pocket pc's without adding any (significant) bulk. There's no reason why the same DSP chip that is used to modem the cellphone signal couldn't be used to also demodulate FM broadcast, GPS signals, etc, all just by running a different program. That is the beauty of DSP. Yeah you might need to switch in and out some final amplifier or mixer stages but thats easy enough and it can all be integrated into a single chip with only a few external components. SHit they already have ham radios that are smaller than some cellphones that operate on 50mhz, 144mhz, 440mhz, and 1.2ghz. If THAT isn't a wide frequency range then I don't know what is.
So my point is there is no TECHNICAL reason NOT to integrate the HELL out of devices. There are many practical reasons why integrated devices rule.
Will this ever happen? Of course not. Well then again, insert $10M and I'll make it. Does anyone want to fund my startup?
Here is a 4 hour sequence of high-res Shreveport imagery. Whats amazing is how long the debris trail lingered in the sky, and the way it disappears so suddenly I almost think they may have adjusted the radar's gain to hide it.
This is a great idea! Hey what is DIRT after all? IT'S DEAD DECOMPOSED ORGANIC MATTER! And thats where food grows. Brown gold. Anyway why is human shit worse than, say, horse shit? or cow shit? or chicken shit? or BAT shit? All make GREAT fertalizer!
The REAL problem with using human waste as fertalizer is that MOST people don't just put thier shit down their sewer, they also put down lots of soap, bleach, and all the other nasties. By the time sewage gets to the treatment plant it's usually so chock full of heavy metals and toxic chemicals that there is nothing else to do with it except dump it into a major body of water and pray that dilution is the solution.
If you keep your piss'n'shit seperate from all the other stuff that usually goes down the drain, then all you have to do is let it set up for a while. Let it break down, an let the e-coli die. Then you're all set. Again, it's the exact same thing they do with cow shit. They dump it all in a big tank, let it sit for a while and digest, and then they spread it all over the fields that are used to grow your food.
So in summation 1. Food loves to grow in dirt. 2. Dirt is shit. 3. Human shit is no worse than x shit, where x is a vertibret life form.
Many (most?) ski resorts world wide do this. I know of several in Vermont at least. The problem is that making snow uses a LOT of water! The only limit to the amount of snow they can make IS the amount of water they can get. And the more snow they make the deeper their base is and longer they can stay open into the spring before it all melts off. SO naturally they want to get as much water as possible.
The ski areas already create huge artificial ponds simple for collecting water during the off season, and also tend to take as much as they can get from any local natural water supplies, such as lakes, rivers and streams. Of course a lot of big ski states like Vermont and Colorado also have a lot of environmentalists that bitterly oppose the ski areas sucking streams dry (which they will do, given the opportunity). So the ski areas tap their HUGE supply of otherwise wasted wastewater.
Environmentally this is great. They super-treat their wastewater and the spread it over a large area. I'm sure it's better for the environment than dumping halfass treated wastewater into natural bodies of water like most localities do.
As for the skiing, well, the snow IS of a somewhat ODD color and odour. YMMV, but I try not to fall down on it.
I'm not sure how many people have noticed, but most railroads are now running radio-controllable locomotives.
I'm a bit of a rail buff and I from time to time I like to go down to the yard and watch them assemble trains. Nowadays the engineers have a large remote control, in the form of a strap-on breastpack. From this control they can pretty much operate all of the primary functions of the train (IE throttle, brake, horn, bell, etc.) This makes it possible for the engineer to build the train essentialy unaided. He can drive the locomotive up to a switch, jump off, drive the whole train past the switch, throw the switch, then back the train all the way down untill the locomotive clears the switch, throw it back and jump back on the locomotive. In the past this operation would have either required two people, one to drive the loco and one to throw the switch, or else the engineer would have to walk the length of the train twice (not really a viable proposition when you've got a mile-long train on a busy line.)
Is it dangerous? Working on the railroad is always dangerous. But in reality it's probably safer than otherwise. Fewer people to keep track of. It's a pretty neat system.
Now IMHO it's fucking retarded that they are planning to use 802.11 for this. BTW the article link is 404 so don't bitch at me for not reading it.
OMG CHEMICALS NO! I HATE CHEMICALS! THOSE FUCKIN THINGS! THERE'S 700 CHEMICALS IN CIGARETTES! I HATE DHMO THE MOST! HERE IS MORE INFO ABOUT DHMO:
Dihydrogen Monoxide (DHMO) is a colorless and odorless chemical compound, also referred to by some as Dihydrogen Oxide, Hydrogen Hydroxide, Hydronium Hydroxide, or simply Hydric acid. Its basis is the unstable radical Hydroxide, the components of which are found in a number of caustic, explosive and poisonous compounds such as Sulfuric Acid, Nitroglycerine and Ethyl Alcohol.
Should I be concerned about Dihydrogen Monoxide? Yes, you should be concerned about DHMO! Although the U.S. Government and the Centers for Disease Control (CDC) do not classify Dihydrogen Monoxide as a toxic or carcinogenic substance (as it does with better known chemicals such as hydrochloric acid and saccharine), DHMO is a constituent of many known toxic substances, diseases and disease-causing agents, environmental hazards and can even be lethal to humans in quantities as small as a thimbleful.
What are some of the dangers associated with DHMO? Each year, Dihydrogen Monoxide is a known causative component in many thousands of deaths and is a major contributor to millions upon millions of dollars in damage to property and the environment.
Heh. One time I found a laptop in a garbage can at the South Street Seaport in NYC. It was a 486 DX2-50 with 16 megs of ram, VGA active matrix LCD, and onboard SCSI of all things. All in all a nice machine once I wiped off the mustard. Until I found out that the hard drive was riddled with bad blocks and scandisk found more every time I ran it. And of course it's a SCSI disk so $$ to replace. I guess that's why it was in the garbage can.
Oh but what data I DID check out on the hard drive revealed that it had belonged to one of the tour boat companies at the seaport there.
6. Can they be easy destroyed or jammed? Jammed, sure. You just need to transmit on the thing's frequency with enough power. Destroyed? Probably. A strong enough RF pulse should do the trick. A microwave would also probably induce enough current in it to fry the chip. Actually a strong enough RF could also destroy the reader!
Of course consider the legal and practical aspects of both courses of action. The FCC takes a very dim view of all jamming activities, and it would be quite simple for anyone with radio experience to track down the source of the jamming signal (IE you.) Tracking an instantanious RF pulse is much more difficult and they'd have to be listening specifically for it, but they could do it.
Your best bet for destroying it is probably to use a microwave, or if it doesn't fit in the microwave take a microwave apart and use the microwave gun.
Disclaimer: DO NOT TRY THIS AT HOME! I am not recommending or suggesting that I or anybody else should or will take any of the aforementioned actions. I cannot be held liable for you burning off your retinas with a microwave gun, or for any other injuries or legal action that may result from doing any of the things I've mentioned. I want to keep my ham radio license.
Incorrect. RFID tags are powered by the reader, it is possible to intercept the tags response to a reader using a high gain antenna, but at the power levels a RFID tag transmits at, it is unlikely you could pick up a RFID response from more than 50m away, even with a large dish.
In a practical sense, yes. You'll notice I used the word "theoretical".
To illicit a response without overhearing an exchange, you would need an extremely directional antenna, and even then you are likely to get multiple responses, which makes it useless.
Incorrect. Page 7 of http://www.microchip.com/download/lit/pline/rfid/g uides/21299d.pdf says
in a growing
number of new applications, the simultaneous reading of several tags in the same RF field is absolutely critical: library books, airline baggage, garment and retail applications are a few. In order to read multiple tags simultaneously, the tag and reader must be designed to detect the condition that more than one tag is active. Otherwise, the tags will all backscatter the carrier at the same time and the amplitude-modulated waveforms shown in Figure 3 and Figure 4 would be garbled. This is referred to as a collision. No data would be transferred to the reader. The tag/reader interface is similar to a serial bus, even though the "bus" travels through the air. In a wired serial bus application, arbitration is necessary to prevent bus contention. The RFID interface also requires arbitration so that only one tag transmits data over the "bus" at one time. A number of different methods are in use and in development today for preventing collisions; most are patented or patent pending. Yet, all are related to making sure that only one tag "talks" (backscatters) at any one time. See the MCRF250 (DS21267), MCRF355/360 (DS21287) and MCRF45X (DS40232) data sheets for various anti-collision algorithms.
4. From how far away can the tag be read? The typical range is a few feet, a la Mobil SpeedPass or tollbooth EZPass. Think about how often you come within a few feet of something that could secretly house an RFID tag reader... The THEORETICAL range limit is a few feet PLUS line-of-sight. A high gain antenna on the reader could read tags from a great distance away, just like your Pringles can 802.11 antenna.
5. Aren't RF tags already on all kinds of stuff as an anti theft measure? No. The RF tags at BestBuy are not ID tags. They don't have a serial number in them. They are ON or OFF. Take one out if you don't belive me, it's just a strip of metal, just like in library books. They are not active devices. An RFID tag is a COMPUTER with RAM and ROM and a data radio.
At most major intersections these days they lay wires in the pavement. You can see the grooves they cut for them. Do you think they REALLY turn the light green? It would be relatively inexpensive for a city to use those wires (or similar wires) to read the RFID tag in EVERY SINGLE TIRE THAT GOES THROUGH THAT INTERSECTION, 24 hours a day, 7 days a week, 365 days a year. You think someone is just going to write those all down?
They could place scanners every 1/4 mile along the interstate and read the tag as your car drives by at 80mph. You're telling me someone could just read your plate in THAT situation?
Any place where there's pavement they could embed readers in it. You're tires are closer than 24 inches to the ground most of the time.
Maybe at tollbooths they could just read your plate, but if they use tollbooths to read your plate AND corrolate it to your tire IDs, then they can track you almost anywhere anytime. Of course many tollbooths ALREADY are equipped with EZPasses. There's voluntary tracking for you.
To everyone who said "if they're close enough to scan your tires they could just read your plate", think harder.
Since a lot of ppl are asking a lot of the same questions about RFID devices, I thought I'd answer some here.
More information can be had from Microchip, a leading manufacturer of RFID devices. A lot of this information is coming from their RFID Design Guide
1. What is an RFID tag? An RFID tag is a very small microcontroller and radio transmitter/receiver. They typically consist of a single chip and a single coil which behaves as an antenna.
2. What does an RFID tag transmit? Most RFID tags transmit a single large integer number, unique to that individual tag. A serial number, if you will. Some RF tags also have a very small amount of ROM/EEPROM, and so could transmit a little more info and can even be reprogrammed by the "reader".
3. How are they powered? The RFID "reader" device emits RF energy. The RFID tag receives this energy and uses it to power itself. It's a lot like an old AM crystal radio. The device transmits its number over and over at a very high bps for a high level of data redundancy.
There is a whole shitload more technical modulation theory and stuff that goes on here which I'm leaving out. If you aren't a ham or other radio type person it would probably be meaningless. Again if you would like more info, look here.
They put in in people inside a capsule thats the size of a grain of rice and most of that size is the capsule. The devices consist of a single TINY microchip (grain of sand size) and a very tiny inductor (two grains of sand size).
The devices are powered by received RF energy, which the "reader" transmits. This isn't crazy, remember crystal AM radios? Did you know that you can listen to AM stations using a reciever that's powered BY the AM signal? Did you know that you can string a long wire parallel to the power lines and steal power from the electric company via electrical induction?
Yeah but people just can't secretly scan your VIN every time you go through a tollbooth, stop at a traffic light (You KNOW that those wires in the road don't really make the light green), or drive through McDonalds.
They legalize weed but label everyone who buys CD-Rs a pirate? I've burned lots of CDs to backup my personal documents, stuff on which I own the copyright.
We should start pirating media via more esoteric mediums, like DLT or mercury delay line, and start doing data backups on VHS, just to fuck with them.
Many Canadien population centers (Toronto, Montreal) are well within range of USA radio and TV broadcasts. I live in Vermont and frequently enjoy the high-quality classic rock programming on CHOM FM and the hilarious BBC comedies on CBC.
any radio signal can be jammed. GPS signals are especially easy to jam because the satelites are 10 thousand miles away and have low power transmitters to begin with since electricity in space is precious.
How big does the device need to be? Not very big. No bigger than a typical GPS receiver. What's FAR more important is the size of your antenna. A nice parabolic dish (say, an old DSS dish) with 24db gain could probably be used to jam a GPS receiver from a mile away while running very low power. A lower gain antenna could be just as effective if the power were higher, though, and would be less directional to boot. They pack 100 watt transmitters into a case the size of a car stereo these days, so the device definately doesn't NEED to be very big.
Of course that's assuming you want to block from a good distance, if you are within about 10 feet of the GPS receiver, you can probably jam it with a few miliwatts of power and a wet piece of string for an antenna. You could make a GPS jamming PC card, or SD card even. Oh wait SD is a stupid closed standard. But a low power unit could be easily be made small enough to, say, jam up your ass.
This isn't new, or revolutionary, or even news worthy. Electronic warfare has been around as long as electronics and the bad guys are always trying to jam the good guys comms and vice versa. Ever since that bozo went on the news and talked about this everyone's had their panties in a bunch. Iraq could probably shit out a couple of ghetto GPS jammers but I doubt if they have the resources to produce the 10,000 units they'd need to really make a measureable difference in the outcome of the war. Oh and by the way we can play the same game by using directional antennas on our receivers to reject jamming signals.
And one final note, anything that emits an RF signal is easily locateable. See radio direction finding, ham radio fox hunts, etc. Shit, our forces could just home in on the jamming signal:)
Did the Apple II bus architecture even have a name? I could never quite get over the fact that certain slots could only be used for certain devices. Well except for slot 7. One general purpose slot... On the other hand a lot of shit seemed to be happy plugging into slot 3, like my lego logo card.
Someday maybe I'll bust out the old IIgs again and try to get some answers, just for shits.
Slashdot Mirror
If you want my advice, set up an IRC server and teach people how to use it. It should be exceedingly easy for you to track all of it's usage. True it might not exactly facilitate people communicating to/from off-campus but it would solve your accountability problem. You could even use Trillian as the client, thus giving people that "IM feel".
Before our campus moved to a fully switched LAN, I used to use Ethereal to sniff my whole dorm's AIM traffic in real time. 80 people, not that much traffic. Even in the evening at peak utilization it was easy to keep up with, no worse than a busy IRC channel. So IMO AIM is not a bandwidth hog.
The protocol itself is not as efficient as it COULD be. I did notice occasional repeated messages, and signon/signoff messages are repeated frequently. But we're still talking about piffiling small bandwidth.
PS I'm just kidding and I didn't actually do anything that I've described in this post. By reading this post you agree that I didn't run a sniffer, or reverse engineer AIM's protocol just by watching it's traffic in a sniffer.
Now just a sec, I LOVED my databank watch! I kept all my BBS numbers in there!
For speaker/mic purposes, use a little earbud headset like a Jabra. Handsfree. They rule. Period. Why does a phone have to look like a phone anyway? Why do you have to hold it to your ear? Bluetooth headsets! Lets get out of the 20th century.
I guess the pocket PC form factor isn't the greatest for gaming, although with the touchscreen... Nevermind, I hate getting fingerprints all over my screen. It could be improved, anyway.
Okay I will admit that one size does not always fit all. But I would still kill to compress my ham radio, AX.25 TNC, pocket pc, and gps receiver into a single unit. APRS baby!
Thats right, they all have a microprocessor, some buttons, and an LCD, and take batteries! Whats the real difference between an iPod and a pocket PC with a big microdrive? Not a lot.
And furthermore, what do all of THESE devices have in common?
Thats right, they have ALL of the same traits as the aforementioned devices, with the addition of an RF DSP chip. Again, a lot of overlap
So whats my point? Sure you could carry one of each of these devices, but do you have enough pocket room? Or room on your belt? Do you want to fuck around with all those batteries and no convenient way to interface the devices to each other? You COULD merge all of these devices into one single SUPER DEVICE.
Sound crazy? It's not. A PocketPC already can do most of this stuff. MP3s (DiVx to boot), games, PIM, whatever other software you want. They've already squeezed cell phones into pocket pc's without adding any (significant) bulk. There's no reason why the same DSP chip that is used to modem the cellphone signal couldn't be used to also demodulate FM broadcast, GPS signals, etc, all just by running a different program. That is the beauty of DSP. Yeah you might need to switch in and out some final amplifier or mixer stages but thats easy enough and it can all be integrated into a single chip with only a few external components. SHit they already have ham radios that are smaller than some cellphones that operate on 50mhz, 144mhz, 440mhz, and 1.2ghz. If THAT isn't a wide frequency range then I don't know what is.
So my point is there is no TECHNICAL reason NOT to integrate the HELL out of devices. There are many practical reasons why integrated devices rule.
Will this ever happen? Of course not. Well then again, insert $10M and I'll make it. Does anyone want to fund my startup?
steel rusts
actually it can only hold two.
http://www.rap.ucar.edu/cgi-bin/neilley/NIDS_archi ve?Radar=SHV&Composite=NONE&Start_date=20030201&St art_time=13&Duration=240&Frequency=0&Parameter =1
Here is a 4 hour sequence of high-res Shreveport imagery. Whats amazing is how long the debris trail lingered in the sky, and the way it disappears so suddenly I almost think they may have adjusted the radar's gain to hide it.
I'd say this is totaly cool, but...
This is a great idea! Hey what is DIRT after all? IT'S DEAD DECOMPOSED ORGANIC MATTER! And thats where food grows. Brown gold. Anyway why is human shit worse than, say, horse shit? or cow shit? or chicken shit? or BAT shit? All make GREAT fertalizer!
The REAL problem with using human waste as fertalizer is that MOST people don't just put thier shit down their sewer, they also put down lots of soap, bleach, and all the other nasties. By the time sewage gets to the treatment plant it's usually so chock full of heavy metals and toxic chemicals that there is nothing else to do with it except dump it into a major body of water and pray that dilution is the solution.
If you keep your piss'n'shit seperate from all the other stuff that usually goes down the drain, then all you have to do is let it set up for a while. Let it break down, an let the e-coli die. Then you're all set. Again, it's the exact same thing they do with cow shit. They dump it all in a big tank, let it sit for a while and digest, and then they spread it all over the fields that are used to grow your food.
So in summation
1. Food loves to grow in dirt.
2. Dirt is shit.
3. Human shit is no worse than x shit, where x is a vertibret life form.
Many (most?) ski resorts world wide do this. I know of several in Vermont at least. The problem is that making snow uses a LOT of water! The only limit to the amount of snow they can make IS the amount of water they can get. And the more snow they make the deeper their base is and longer they can stay open into the spring before it all melts off. SO naturally they want to get as much water as possible.
The ski areas already create huge artificial ponds simple for collecting water during the off season, and also tend to take as much as they can get from any local natural water supplies, such as lakes, rivers and streams. Of course a lot of big ski states like Vermont and Colorado also have a lot of environmentalists that bitterly oppose the ski areas sucking streams dry (which they will do, given the opportunity). So the ski areas tap their HUGE supply of otherwise wasted wastewater.
Environmentally this is great. They super-treat their wastewater and the spread it over a large area. I'm sure it's better for the environment than dumping halfass treated wastewater into natural bodies of water like most localities do.
As for the skiing, well, the snow IS of a somewhat ODD color and odour. YMMV, but I try not to fall down on it.
I'm not sure how many people have noticed, but most railroads are now running radio-controllable locomotives.
I'm a bit of a rail buff and I from time to time I like to go down to the yard and watch them assemble trains. Nowadays the engineers have a large remote control, in the form of a strap-on breastpack. From this control they can pretty much operate all of the primary functions of the train (IE throttle, brake, horn, bell, etc.) This makes it possible for the engineer to build the train essentialy unaided. He can drive the locomotive up to a switch, jump off, drive the whole train past the switch, throw the switch, then back the train all the way down untill the locomotive clears the switch, throw it back and jump back on the locomotive. In the past this operation would have either required two people, one to drive the loco and one to throw the switch, or else the engineer would have to walk the length of the train twice (not really a viable proposition when you've got a mile-long train on a busy line.)
Is it dangerous? Working on the railroad is always dangerous. But in reality it's probably safer than otherwise. Fewer people to keep track of. It's a pretty neat system.
Now IMHO it's fucking retarded that they are planning to use 802.11 for this. BTW the article link is 404 so don't bitch at me for not reading it.
Apperantly monster.com is doing okay (or is gambling on spending $$$ on advertising), since we were just graced with their superbowl commercial.
OMG CHEMICALS NO! I HATE CHEMICALS! THOSE FUCKIN THINGS! THERE'S 700 CHEMICALS IN CIGARETTES! I HATE DHMO THE MOST! HERE IS MORE INFO ABOUT DHMO:
Dihydrogen Monoxide (DHMO) is a colorless and odorless chemical compound, also referred to by some as Dihydrogen Oxide, Hydrogen Hydroxide, Hydronium Hydroxide, or simply Hydric acid. Its basis is the unstable radical Hydroxide, the components of which are found in a number of caustic, explosive and poisonous compounds such as Sulfuric Acid, Nitroglycerine and Ethyl Alcohol.
Should I be concerned about Dihydrogen Monoxide?
Yes, you should be concerned about DHMO! Although the U.S. Government and the Centers for Disease Control (CDC) do not classify Dihydrogen Monoxide as a toxic or carcinogenic substance (as it does with better known chemicals such as hydrochloric acid and saccharine), DHMO is a constituent of many known toxic substances, diseases and disease-causing agents, environmental hazards and can even be lethal to humans in quantities as small as a thimbleful.
What are some of the dangers associated with DHMO?
Each year, Dihydrogen Monoxide is a known causative component in many thousands of deaths and is a major contributor to millions upon millions of dollars in damage to property and the environment.
BAN DHMO TODAY!
http://www.dhmo.org
Heh. One time I found a laptop in a garbage can at the South Street Seaport in NYC. It was a 486 DX2-50 with 16 megs of ram, VGA active matrix LCD, and onboard SCSI of all things. All in all a nice machine once I wiped off the mustard. Until I found out that the hard drive was riddled with bad blocks and scandisk found more every time I ran it. And of course it's a SCSI disk so $$ to replace. I guess that's why it was in the garbage can.
Oh but what data I DID check out on the hard drive revealed that it had belonged to one of the tour boat companies at the seaport there.
6. Can they be easy destroyed or jammed?
Jammed, sure. You just need to transmit on the thing's frequency with enough power.
Destroyed? Probably. A strong enough RF pulse should do the trick. A microwave would also probably induce enough current in it to fry the chip. Actually a strong enough RF could also destroy the reader!
Of course consider the legal and practical aspects of both courses of action. The FCC takes a very dim view of all jamming activities, and it would be quite simple for anyone with radio experience to track down the source of the jamming signal (IE you.) Tracking an instantanious RF pulse is much more difficult and they'd have to be listening specifically for it, but they could do it.
Your best bet for destroying it is probably to use a microwave, or if it doesn't fit in the microwave take a microwave apart and use the microwave gun.
Disclaimer: DO NOT TRY THIS AT HOME! I am not recommending or suggesting that I or anybody else should or will take any of the aforementioned actions. I cannot be held liable for you burning off your retinas with a microwave gun, or for any other injuries or legal action that may result from doing any of the things I've mentioned. I want to keep my ham radio license.
In a practical sense, yes. You'll notice I used the word "theoretical".
Incorrect. Page 7 of http://www.microchip.com/download/lit/pline/rfid/
4. From how far away can the tag be read?
The typical range is a few feet, a la Mobil SpeedPass or tollbooth EZPass. Think about how often you come within a few feet of something that could secretly house an RFID tag reader... The THEORETICAL range limit is a few feet PLUS line-of-sight. A high gain antenna on the reader could read tags from a great distance away, just like your Pringles can 802.11 antenna.
5. Aren't RF tags already on all kinds of stuff as an anti theft measure?
No. The RF tags at BestBuy are not ID tags. They don't have a serial number in them. They are ON or OFF. Take one out if you don't belive me, it's just a strip of metal, just like in library books. They are not active devices. An RFID tag is a COMPUTER with RAM and ROM and a data radio.
At most major intersections these days they lay wires in the pavement. You can see the grooves they cut for them. Do you think they REALLY turn the light green? It would be relatively inexpensive for a city to use those wires (or similar wires) to read the RFID tag in EVERY SINGLE TIRE THAT GOES THROUGH THAT INTERSECTION, 24 hours a day, 7 days a week, 365 days a year. You think someone is just going to write those all down?
They could place scanners every 1/4 mile along the interstate and read the tag as your car drives by at 80mph. You're telling me someone could just read your plate in THAT situation?
Any place where there's pavement they could embed readers in it. You're tires are closer than 24 inches to the ground most of the time.
Maybe at tollbooths they could just read your plate, but if they use tollbooths to read your plate AND corrolate it to your tire IDs, then they can track you almost anywhere anytime. Of course many tollbooths ALREADY are equipped with EZPasses. There's voluntary tracking for you.
To everyone who said "if they're close enough to scan your tires they could just read your plate", think harder.
Since a lot of ppl are asking a lot of the same questions about RFID devices, I thought I'd answer some here.
More information can be had from Microchip, a leading manufacturer of RFID devices. A lot of this information is coming from their RFID Design Guide
1. What is an RFID tag?
An RFID tag is a very small microcontroller and radio transmitter/receiver. They typically consist of a single chip and a single coil which behaves as an antenna.
2. What does an RFID tag transmit?
Most RFID tags transmit a single large integer number, unique to that individual tag. A serial number, if you will. Some RF tags also have a very small amount of ROM/EEPROM, and so could transmit a little more info and can even be reprogrammed by the "reader".
3. How are they powered?
The RFID "reader" device emits RF energy. The RFID tag receives this energy and uses it to power itself. It's a lot like an old AM crystal radio. The device transmits its number over and over at a very high bps for a high level of data redundancy.
There is a whole shitload more technical modulation theory and stuff that goes on here which I'm leaving out. If you aren't a ham or other radio type person it would probably be meaningless. Again if you would like more info, look here.
They put in in people inside a capsule thats the size of a grain of rice and most of that size is the capsule. The devices consist of a single TINY microchip (grain of sand size) and a very tiny inductor (two grains of sand size).
a ts/rfid/index.htm, which manufactures a whole line of the devices.
The devices are powered by received RF energy, which the "reader" transmits. This isn't crazy, remember crystal AM radios? Did you know that you can listen to AM stations using a reciever that's powered BY the AM signal? Did you know that you can string a long wire parallel to the power lines and steal power from the electric company via electrical induction?
You can read ALL about commercial RFID systems at http://www.microchip.com/1010/pline/frequency/rfc
Yeah but people just can't secretly scan your VIN every time you go through a tollbooth, stop at a traffic light (You KNOW that those wires in the road don't really make the light green), or drive through McDonalds.
They legalize weed but label everyone who buys CD-Rs a pirate? I've burned lots of CDs to backup my personal documents, stuff on which I own the copyright.
We should start pirating media via more esoteric mediums, like DLT or mercury delay line, and start doing data backups on VHS, just to fuck with them.
Many Canadien population centers (Toronto, Montreal) are well within range of USA radio and TV broadcasts. I live in Vermont and frequently enjoy the high-quality classic rock programming on CHOM FM and the hilarious BBC comedies on CBC.
any radio signal can be jammed. GPS signals are especially easy to jam because the satelites are 10 thousand miles away and have low power transmitters to begin with since electricity in space is precious.
:)
How big does the device need to be? Not very big. No bigger than a typical GPS receiver. What's FAR more important is the size of your antenna. A nice parabolic dish (say, an old DSS dish) with 24db gain could probably be used to jam a GPS receiver from a mile away while running very low power. A lower gain antenna could be just as effective if the power were higher, though, and would be less directional to boot. They pack 100 watt transmitters into a case the size of a car stereo these days, so the device definately doesn't NEED to be very big.
Of course that's assuming you want to block from a good distance, if you are within about 10 feet of the GPS receiver, you can probably jam it with a few miliwatts of power and a wet piece of string for an antenna. You could make a GPS jamming PC card, or SD card even. Oh wait SD is a stupid closed standard. But a low power unit could be easily be made small enough to, say, jam up your ass.
This isn't new, or revolutionary, or even news worthy. Electronic warfare has been around as long as electronics and the bad guys are always trying to jam the good guys comms and vice versa. Ever since that bozo went on the news and talked about this everyone's had their panties in a bunch. Iraq could probably shit out a couple of ghetto GPS jammers but I doubt if they have the resources to produce the 10,000 units they'd need to really make a measureable difference in the outcome of the war. Oh and by the way we can play the same game by using directional antennas on our receivers to reject jamming signals.
And one final note, anything that emits an RF signal is easily locateable. See radio direction finding, ham radio fox hunts, etc. Shit, our forces could just home in on the jamming signal
Did the Apple II bus architecture even have a name? I could never quite get over the fact that certain slots could only be used for certain devices. Well except for slot 7. One general purpose slot... On the other hand a lot of shit seemed to be happy plugging into slot 3, like my lego logo card.
Someday maybe I'll bust out the old IIgs again and try to get some answers, just for shits.
Dude, you forgot about NuBus!