FRIHOST FORUMS SEARCH FAQ TOS BLOGS COMPETITIONS
You are invited to Log in or Register a free Frihost Account!


Open your car from 1 Km away.





chatrack
Hi,

I just want to share my experience and find a reason for the happening.

I have a car with remote control to open/close doors (secrurity system).
It works with in 100 to 150 meters.

But i could open it from a very large distance!

What i do is, i ask my friend to stand near the car with his mobile phone(GSM) in his hand.

Then I mooved to large distance (with remote key in my pocket).

Then I call my friend in his mobile from my mobile.

As we talking, i pressed the remote button.

VAAH.. "the door opens with its sound"... I could close it also.

So, it was really amazing , becouse we where about 1 km distance.
Still the car remote can do its job.



Now my question is that , how this mobile conversation help.. for more remote power?
Afaceinthematrix
This does not work with every key. I have tried it with several cars and it has only worked with a few.
ocalhoun
Strange... That would only make sense if the remote used an audio signal to control the car...
Afaceinthematrix
ocalhoun wrote:
Strange... That would only make sense if the remote used an audio signal to control the car...


That's what I figured, but I didn't say it in case I was incorrect. Some remotes must do this because what he/she said works with some remotes.... but like I said, I have tried it with numerous cars and it has only worked a couple of times.
ocalhoun
Afaceinthematrix wrote:
ocalhoun wrote:
Strange... That would only make sense if the remote used an audio signal to control the car...


That's what I figured, but I didn't say it in case I was incorrect. Some remotes must do this because what he/she said works with some remotes.... but like I said, I have tried it with numerous cars and it has only worked a couple of times.

With analog phones or digital?
deanhills
Wonder whether one can activate a bomb that way long-distance? You can attach an open phone below a car and then phone from as far as Al Qeda in Afghanistan? Shocked
Helios
Maybe the signal connecting between the phones acted like a carrier signal transferring the signal from the remote to the car. Just an assumption, I'll need to think about this. It's rather interesting LOL

About the audio activation, maybe somehow you can check whether the remote has a built in tweeter / beeper ?
I really doubt it uses audio activation though...
Afaceinthematrix
ocalhoun wrote:
Afaceinthematrix wrote:
ocalhoun wrote:
Strange... That would only make sense if the remote used an audio signal to control the car...


That's what I figured, but I didn't say it in case I was incorrect. Some remotes must do this because what he/she said works with some remotes.... but like I said, I have tried it with numerous cars and it has only worked a couple of times.

With analog phones or digital?


Digital. I used my at&t cellular phone...
Magicman
Are you sure that you were out of the normal range of the remotes? Every source online that seems reputable says that this is simply an urban legend. No one seems to be able to come up with a reason why this should work.
Afaceinthematrix
When I tried it, I was out of the range of the remotes. The person drove down the street several hundred meters. I then tried multiple times to unlock it with a spare remote. According to the driver, nothing happened. I then called the person and tried it and the car unlocked. So it was definitely out of the range of the remotes because I tested it before calling, although there is the possibility that because it was just a few hundred meters, the signal could have been strengthened because of the cell phones. I wouldn't be surprised if that was the case because I do not see how this would work (because it's radio waves vs. sound waves), but I know for a fact (because I tested and observed it), that it will work over short distances that are barely out of range.
Agent ME
Sounds like something they should test on Mythbusters or have on Snopes.

I wonder what else could possibly work with the type of trick? Maybe even certain types of RF remotes (not IR remotes)?
Magicman
Agent ME wrote:
Sounds like something they should test on Mythbusters or have on Snopes.


It was Busted on Mythbusters (http://www.youtube.com/watch?v=oC_YdJeXouE) and called a hoax on Snopes (http://www.snopes.com/autos/techno/keyless.asp).
Parkour_Jarrod
Helios wrote:
Maybe the signal connecting between the phones acted like a carrier signal transferring the signal from the remote to the car. Just an assumption, I'll need to think about this. It's rather interesting LOL

About the audio activation, maybe somehow you can check whether the remote has a built in tweeter / beeper ?
I really doubt it uses audio activation though...


Your right it is tranferring the signal the radiowaves from the phone pick up the radiowaves from the key (it sends out a frequency thats picked up by your car) passing it through the other person's phone making the car pick it up therefore unlocking
ocalhoun
deanhills wrote:
Wonder whether one can activate a bomb that way long-distance? You can attach an open phone below a car and then phone from as far as Al Qeda in Afghanistan? Shocked

Terrorists have been using cell-phone triggered bombs in IED's for a long time now. They attach the ringer-speaker wires of the cell phone to the trigger of the bomb, retreat to a safe distance, and when the target is close, they call the number. The cell phone rings, sending an electric signal through the speaker wires, which triggers the bomb. That doesn't require the use of any car remotes though.

Helios wrote:
Maybe the signal connecting between the phones acted like a carrier signal transferring the signal from the remote to the car.

Wouldn't work with a digital phone, because the signal is broken up, separated, re-interpreted, sent as 1's and 0's along a land-line, then converted to a digital wireless signal:
Afaceinthematrix wrote:


Digital. I used my at&t cellular phone...


Quote:

Your right it is tranferring the signal the radiowaves from the phone pick up the radiowaves from the key (it sends out a frequency thats picked up by your car) passing it through the other person's phone making the car pick it up therefore unlocking

Phones are built to transfer only a small range of audio frequencies. (Not even the full audio range, just the range of normal human voices.)
Parkour_Jarrod
ocalhoun wrote:
deanhills wrote:
Wonder whether one can activate a bomb that way long-distance? You can attach an open phone below a car and then phone from as far as Al Qeda in Afghanistan? Shocked

Terrorists have been using cell-phone triggered bombs in IED's for a long time now. They attach the ringer-speaker wires of the cell phone to the trigger of the bomb, retreat to a safe distance, and when the target is close, they call the number. The cell phone rings, sending an electric signal through the speaker wires, which triggers the bomb. That doesn't require the use of any car remotes though.

Helios wrote:
Maybe the signal connecting between the phones acted like a carrier signal transferring the signal from the remote to the car.

Wouldn't work with a digital phone, because the signal is broken up, separated, re-interpreted, sent as 1's and 0's along a land-line, then converted to a digital wireless signal:
Afaceinthematrix wrote:


Digital. I used my at&t cellular phone...


Quote:

Your right it is transferring the signal the radio waves from the phone pick up the radiowaves from the key (it sends out a frequency thats picked up by your car) passing it through the other person's phone making the car pick it up therefore unlocking

Phones are built to transfer only a small range of audio frequencies. (Not even the full audio range, just the range of normal human voices.)


Actually what i mean is the 0's and 1's that you mentioned before which is why it only works on digital handsets, a car remote's locking isn't by audio its by sending a signal to your car, so it picks up the signal being sent in a 360 range by the remote then being hitched on to the signal the digital phone sends (like a Trojan virus on a computer) and delivering itself to your friend who is at you car (or vice versa)
ocalhoun
Parkour_Jarrod wrote:

Actually what i mean is the 0's and 1's that you mentioned before which is why it only works on digital handsets, a car remote's locking isn't by audio its by sending a signal to your car, so it picks up the signal being sent in a 360 range by the remote then being hitched on to the signal the digital phone sends (like a Trojan virus on a computer) and delivering itself to your friend who is at you car (or vice versa)

Hitched on the signal like a Trojan virus on a computer? An RF signal? Not at all possible, unless the car remote's signal is: 1) On the same frequency as the cell phone, 2) digital, and 3) programmed to insert itself into digital cell phone signals.

And this talk of the car remote using the cell phone signal as a carrier wave is ignorant.
-Intelligence signals need to be added to a carrier wave deliberately, using transistors to modify the carrier wave based on the strength of the signal. This would have to be done INSIDE the phone, and wouldn't happen by accident.
-The switching equipment at the cell phone tower wouldn't transfer the intelligence signal (car signal), because it would determine that it was signal noise, and eliminate it before re-broadcasting it to the second phone.
-A carrier wave needs to be a steady signal, not one that is already modulated with voice signals.
redslazers
ocalhoun wrote:
Strange... That would only make sense if the remote used an audio signal to control the car...


but then wouldn't someone who wants to steal the car just play all the possible sounds to open the car using a device which can emit the required frequency?
ocalhoun
redslazers wrote:

but then wouldn't someone who wants to steal the car just play all the possible sounds to open the car using a device which can emit the required frequency?

The same thing goes for RF signals, if you played all possible signals, eventually you'd get the right one.

What prevents this is the number of possible signals, which (depending on the receiver's limitations) could be infinite. That means that our intrepid electronics-savvy thief would have to wait a very, very long time before his unlocking device finally produced the right signal. Its just like the password to log on to your computer. If you gave it every possible password, eventually you'd get in, but that would take a very long time.

A much better way to do it would be to build a receiver-recorder-transmitter device for the right frequency. Wait for a person to approach their car, and push the receive/record button. When the car unlocks, press the stop button. When you see the same car parked again, press the playback/transmit button, and the car will unlock.
chatrack
Afaceinthematrix wrote:
When I tried it, I was out of the range of the remotes. The person drove down the street several hundred meters. I then tried multiple times to unlock it with a spare remote. According to the driver, nothing happened. I then called the person and tried it and the car unlocked. So it was definitely out of the range of the remotes because I tested it before calling, although there is the possibility that because it was just a few hundred meters, the signal could have been strengthened because of the cell phones. I wouldn't be surprised if that was the case because I do not see how this would work (because it's radio waves vs. sound waves), but I know for a fact (because I tested and observed it), that it will work over short distances that are barely out of range.


I would like to add this:
Range of this system is infinite becouse what we are doing is making Low frequency disturbence ( such as code send from a tv remote control to tv sensor) on the Microwave carrier of the Mobile phone.

So it can work even with international call, only thing is that the two mobile phones whould be of same frequency range type
ocalhoun
chatrack wrote:


I would like to add this:
Range of this system is infinite becouse what we are doing is making Low frequency disturbence ( such as code send from a tv remote control to tv sensor) on the Microwave carrier of the Mobile phone.

So it can work even with international call, only thing is that the two mobile phones whould be of same frequency range type

I'd like to add that you don't understand how the cell phone system works.

1- voice is converted to digitial electric signals by electronics in your phone
2- the transmitter in your phone modulates a carrier wave (800mhz or 1900mhz I think) with those digital signals
3- the cell phone tower picks up that signal, and demodulates that signal back to a digital electrical signal: the tower doesn't convert anything except the digital signal it is looking for- everything else is discarded as noise
4- the electrical signal (1's and 0's) goes to a switching unit in the tower
5- the switching unit determines where the destination for the signal is
6- the switching unit either sends that digital electrical signal along a fiber-optic line to another switching unit, or through a copper line back to the same tower.
7- once the electrical signal has traveled via either copper, fiber optic, or satellite microwave link, to the tower that the receiving phone is at, that tower modulates a different carrier wave with the digital signal
8- the new tower radiates that modulated signal out, which is picked up by the receiving phone.
9- the second cell phone demodulates the digital signal
10- the second phone converts the digital signal to audio, and then plays that audio through a speaker.


The car remote's signal cannot 'ride' the cell phone's carrier wave, because when that carrier wave gets to the tower, it is stripped away. Then a new carrier wave is created (without any possible car remote signals riding on it) and sent to the other phone.
Parkour_Jarrod
ocalhoun wrote:
chatrack wrote:


I would like to add this:
Range of this system is infinite becouse what we are doing is making Low frequency disturbence ( such as code send from a tv remote control to tv sensor) on the Microwave carrier of the Mobile phone.

So it can work even with international call, only thing is that the two mobile phones whould be of same frequency range type

I'd like to add that you don't understand how the cell phone system works.

1- voice is converted to digitial electric signals by electronics in your phone
2- the transmitter in your phone modulates a carrier wave (800mhz or 1900mhz I think) with those digital signals
3- the cell phone tower picks up that signal, and demodulates that signal back to a digital electrical signal: the tower doesn't convert anything except the digital signal it is looking for- everything else is discarded as noise
4- the electrical signal (1's and 0's) goes to a switching unit in the tower
5- the switching unit determines where the destination for the signal is
6- the switching unit either sends that digital electrical signal along a fiber-optic line to another switching unit, or through a copper line back to the same tower.
7- once the electrical signal has traveled via either copper, fiber optic, or satellite microwave link, to the tower that the receiving phone is at, that tower modulates a different carrier wave with the digital signal
8- the new tower radiates that modulated signal out, which is picked up by the receiving phone.
9- the second cell phone demodulates the digital signal
10- the second phone converts the digital signal to audio, and then plays that audio through a speaker.


The car remote's signal cannot 'ride' the cell phone's carrier wave, because when that carrier wave gets to the tower, it is stripped away. Then a new carrier wave is created (without any possible car remote signals riding on it) and sent to the other phone.


Well just to point out that its 1e^9Hz..



AND Car Remotes ha ve the same range within its range (microwaves), you can unlock a car by making a phonecall next to the car with the right phone....I know, it has happened to me... hung up, checked what was wrong with car if anyone around, nothing, made call again, car locked...
joostvane
It is not possible. A) You are trying to spread the word of the myth and faking Razz or B) some special guy that has superpowers. Both of the movies of the tv show assured us that it is not possible, I believe them.
samjog
Well i dont really understand what you talking about (You physics have your own language! Smile ) But the thing mentioned at first post is just wonderful. Never heard about that before, have to try someday. Science and technologies suprise us everyday, it just can kill me! Surprised
ocalhoun
samjog wrote:
i dont really understand what you talking about

Therefore,
Quote:
Science and technologies suprise us everyday,

If you don't understand it, no wonder it often surprises you. ^.^
snowynight
Well, is that true? I can hardly believe it because it didn't work when i tried.
ptpmonitor
Well, it is really interesting and tough to believe. If you can open your car door in this way, then I think by taking the help of cell phone, you can even open it from other countries. By the way, I think remote signals mixed with mobile phone signal and it happened for this reason. Not sure and totally from guess. As both are electro-magnetic wave, it might be possible. By the way, I will ask our physics professor about it.
ocalhoun
ptpmonitor wrote:
As both are electro-magnetic wave, it might be possible.

<.<
As are TV signals, radio, light, and even the massive amount of 60Hz noise from the power grid.

By the same reasoning, if you shine a flashlight from the top of a radio tower, the flashlight beam should shine thousands of times as far. They are, after all, both electro-magnetic waves...
tony
chatrack wrote:
Hi,

I just want to share my experience and find a reason for the happening.

I have a car with remote control to open/close doors (secrurity system).
It works with in 100 to 150 meters.

But i could open it from a very large distance!

What i do is, i ask my friend to stand near the car with his mobile phone(GSM) in his hand.

Then I mooved to large distance (with remote key in my pocket).

Then I call my friend in his mobile from my mobile.

As we talking, i pressed the remote button.

VAAH.. "the door opens with its sound"... I could close it also.

So, it was really amazing , becouse we where about 1 km distance.
Still the car remote can do its job.



Now my question is that , how this mobile conversation help.. for more remote power?


Yes! I have heard about this feature for some keys. Isn't it crazy? I should try it out some time Razz Razz really 1 km is no limit, if it can be transmitted through the phone system - for we could be on the other side of the planet and do it Wink
ocalhoun
tony wrote:
if it can be transmitted through the phone system

it can't
michaeljscott93
That sounds awesome!!!

Where did you get this system?
fx-trading-education
Instead of enjoying it you should be very scared. If you could open a car with just the sound of your key then anybody who records this sound can open your car
chatrack
fx-trading-education wrote:
Instead of enjoying it you should be very scared. If you could open a car with just the sound of your key then anybody who records this sound can open your car


i think you can do it , if u can record in UHF and reproduce it
ocalhoun
chatrack wrote:
fx-trading-education wrote:
Instead of enjoying it you should be very scared. If you could open a car with just the sound of your key then anybody who records this sound can open your car


i think you can do it , if u can record in UHF and reproduce it

It's perfectly possible. All you need is a good knowledge of electronics, and to know what frequencies the remotes work on.
[FuN]goku
fx-trading-education wrote:
Instead of enjoying it you should be very scared. If you could open a car with just the sound of your key then anybody who records this sound can open your car
I was thinking that also.. Kinda like how phone phreaks use red boxing.
slashnburn99
place the key to your head

then point at the car

for some reason this helps open the car from further away
ocalhoun
slashnburn99 wrote:
place the key to your head

then point at the car

for some reason this helps open the car from further away

Because the transmitter is higher up- better able to clear obstructions. Holding it above your head should work even better.
rasheed
We cannot unlock car doors using 2 gsm mobiles on both ends.....The car key signal is in MHz range whereas te gsm mobile includes Low Pass Filter which removes and EM signal above 4kHz...Therefore the car key stroke EM signal gets removed as soon as it would pass through this LP filter contained in every GSM mobile.
Bikerman
Interesting - you sound like you have some expertise in this....?
Josso
tl;dr

I have opened my car from 1km plenty of times just find a metal signpost and put your key up against it.
chatrack
Josso wrote:
tl;dr

I have opened my car from 1km plenty of times just find a metal signpost and put your key up against it.


So it mean you are using signpost as an antenna reflector
Bikerman
Well, placing the unit against the skull certainly increases the range - I have tried it several times in several different situations and each time it gives an increased range of between around 10-30%. In one case it doubled the range.
Now, the theory that the object is acting as a simple dipole antenna would therefore seem to need some refinement.
If the frequency is in the 300-400Mhz range that gives a wavelength of around 3/4 metre if my mental arithmetic is up to scratch (I'd be grateful if someone would sanity-check that just in case).

Now, how can this be working (and it certainly DOES work - and I have controlled for other factors such as increased height of the fob)?
At first thought, I would assumethe head makes a pretty crappy antenna, unless it is possibly acting as a Yagi dipole - so I wonder if it is, instead, simply altering the capacitance of the transmitter circuit via the proximity effect?
f = 1/(2*pi(sqrt(LC)))

There again - clearly the body is a better conductor than air, so we now have capacitance coupling to a conductive body - that should account for it.....I think.....anyone else care to come in?
ocalhoun
Bikerman wrote:
Well, placing the unit against the skull certainly increases the range - I have tried it several times in several different situations and each time it gives an increased range of between around 10-30%. In one case it doubled the range.
Now, the theory that the object is acting as a simple dipole antenna would therefore seem to need some refinement.
If the frequency is in the 300-400Mhz range that gives a wavelength of around 3/4 metre if my mental arithmetic is up to scratch (I'd be grateful if someone would sanity-check that just in case).

Now, how can this be working (and it certainly DOES work - and I have controlled for other factors such as increased height of the fob)?
At first thought, I would assumethe head makes a pretty crappy antenna, unless it is possibly acting as a Yagi dipole - so I wonder if it is, instead, simply altering the capacitance of the transmitter circuit via the proximity effect?
f = 1/(2*pi(sqrt(LC)))

There again - clearly the body is a better conductor than air, so we now have capacitance coupling to a conductive body - that should account for it.....I think.....anyone else care to come in?


Perhaps the signal is merely reflecting off one's head, increasing the power by up to 50% by decreasing the area of effect by the same amount? (ie, very roughly focusing the beam in a particular direction rather than broadcasting in all directions like it normally does.)
I think most of the wave would go through rather than reflecting though, so I doubt that this alone could explain the gains people are talking about.
Bikerman
I wonder how much reflection you would get - I think the human body is pretty opaque at the 4MHz range.....
ocalhoun
I wonder if a dish reflector could focus the transmission even better and allow for even longer ranges?

*edit*
Idea!

1: Make a little dish reflector for car remotes -- make it foldable so it's pocket sized.
2: Sell it on infomercials
3: Profit!
milkshake01
It would be quite dangerous to lose the remote. Thives could enter your car and take your items.
ocalhoun
milkshake01 wrote:
It would be quite dangerous to lose the remote. Thives could enter your car and take your items.

Thieves have much easier ways to enter your car, starting with a good old fashioned brick.
harrer
It's a hoax. In all the cases this has worked is only when the remote uses the phone's antenna to extend it's own range, not to mention humans are good antennas themselves.
asnani04
This seems a little outlandish, but since its true, there must be something working over there. As a few of you quoted, an audio signal used by the remote control might be a reason, i.e. electromagnetic waves operating in the wavelength range of audio waves. Or maybe there's something else behind this? I would really like to know the right reason behind this observation.
chatrack
asnani04 wrote:
an audio signal used by the remote control might be a reason


Another reason is, some harmonic frequency (multiple frequencies of fundamental GSM mobile)
of GSM mobile carrier wave is some were near the car remote working frequency..this is making
interference in the car remote circuit..making it false switch the logic circuits.
Related topics
What countries did you visit?
amazing fact
Whats your views on alcohol?
Trains versus Cars
Fuel Prices!!!
Are You Addicted To The Internet?
i want thinner legs
Why Not Pakistan !!!
Peechi
Mumbai
In 2013 the sun will release big wind?
What exactly is pin-drop silence?
Problem of pen drive
Minus 2 On The Commute To Work Yesterday...
Reply to topic    Frihost Forum Index -> Science -> General Science

FRIHOST HOME | FAQ | TOS | ABOUT US | CONTACT US | SITE MAP
© 2005-2011 Frihost, forums powered by phpBB.