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  1. #1
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    Default What if... (IR emitter modifications/tweaks)

    First of all Hello everyone, lemme introduce myself: I'm Aldo from italy, the owner of a land rover defender, paited white, with additional headlights and a roof mounted offroad bar with 4 lights... all of their diameters is 20cm... i think this is the perfect setup to be a bull's eye for LIDARs and not even the application of laserveil will make my truck fitted for jammers, even the m45....

    Since that my idea:
    What will happen if i manage to get a m45, open the emitters apart (lenses etc) and replace the IR LEDs with some class III 250mw IR laser diodes? the brilliance should become 20 time higher thus literally blinding the LIDAR. But there is a chance that the beam will become too narrow, even with the lenses, laser in facts does not provide the lighting angle of a LED.

    Another question i have is about the pulsation scheme/pattern of blinder: is it regulating teh beam to flash back based on the LIDAR beams or it just turns on and emit a single prefixed flashing pattern?

    Thanks in advance

  2. #2
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    Default Re: What if... (IR emitter modifications/tweaks)

    Quote Originally Posted by Adonai View Post
    First of all Hello everyone, lemme introduce myself: I'm Aldo from italy, the owner of a land rover defender, paited white, with additional headlights and a roof mounted offroad bar with 4 lights... all of their diameters is 20cm... i think this is the perfect setup to be a bull's eye for LIDARs and not even the application of laserveil will make my truck fitted for jammers, even the m45....

    Since that my idea:
    What will happen if i manage to get a m45, open the emitters apart (lenses etc) and replace the IR LEDs with some class III 250mw IR laser diodes? the brilliance should become 20 time higher thus literally blinding the LIDAR. But there is a chance that the beam will become too narrow, even with the lenses, laser in facts does not provide the lighting angle of a LED.

    Another question i have is about the pulsation scheme/pattern of blinder: is it regulating teh beam to flash back based on the LIDAR beams or it just turns on and emit a single prefixed flashing pattern?

    Thanks in advance
    Sounds like a good idea and theoretically is possible. As far as the pulse rate goes it is not fixed it is based on the pulse rate of the gun.

  3. #3
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    Default Re: What if... (IR emitter modifications/tweaks)

    Guys of LIDAR - Laser Jammer Test - March 2007

    Scroll all the way to the bottom...i think Quad LI's w/ no plate and laser Veil could do something for you

    Li even makes High Powered ones on their site now..so if you got the cash..
    Last edited by Montu; 11-10-2008 at 12:35 PM.

  4. #4
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    Default Re: What if... (IR emitter modifications/tweaks)

    Welcome to the forum!

    Quote Originally Posted by Adonai View Post
    What will happen if i manage to get a m45, open the emitters apart (lenses etc) and replace the IR LEDs with some class III 250mw IR laser diodes?
    Honestly? Say you were able to open up a Blinder head and chip off the epoxy without damagaing it. Then, you did a 1:1 replacement of the LEDs with Laser Diodes. The end result would most likely be a non-working jammer and several hundred dollars worth of burnt-up Laser Diodes due to them not being driven properly.

    At minimum, you would have to re-design the driver circuit... so this quickly becomes impractical especially with other solutions already out there.

    Quote Originally Posted by Adonai View Post
    Another question i have is about the pulsation scheme/pattern of blinder: is it regulating teh beam to flash back based on the LIDAR beams
    Yes, all modern jammers work this way. For more info, see my post in this thread:
    http://www.radardetector.net/forums/...wikipedia.html

  5. #5
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    Default Re: What if... (IR emitter modifications/tweaks)

    Quote Originally Posted by jimbonzzz View Post
    Welcome to the forum!



    Honestly? Say you were able to open up a Blinder head and chip off the epoxy without damagaing it. Then, you did a 1:1 replacement of the LEDs with Laser Diodes. The end result would most likely be a non-working jammer and several hundred dollars worth of burnt-up Laser Diodes due to them not being driven properly.

    At minimum, you would have to re-design the driver circuit... so this quickly becomes impractical especially with other solutions already out there.



    Yes, all modern jammers work this way. For more info, see my post in this thread:
    http://www.radardetector.net/forums/...wikipedia.html
    Teach me oh great one.Your knowledge overflows!!!

  6. #6
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    Default Re: What if... (IR emitter modifications/tweaks)

    Quote Originally Posted by BLINDER-GUY View Post
    Teach me oh great one.Your knowledge overflows!!!

  7. #7

    Default Re: What if... (IR emitter modifications/tweaks)

    One thing I don't understand : do the laser always use the
    same window time frame ?

    The same window frame either the target is @ 200' or 1000' ?

    My theory is that the laser shoots
    his first burst then wait for the return before
    sending the next and so on , untill it computes
    the change in distance over +- 40 burst.

    Could it be so simple that the only move the
    jammer has to do is interpreting the pulse rate
    of the laser and shoot at the same frequency ???

    Will I pass my jam exam Porfessor Jim ?

  8. #8
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    Default Re: What if... (IR emitter modifications/tweaks)

    Thanks alot Jimbonzzz you re very kind and exhaustive

    I red other thread's explanation post, wonderful job

  9. #9
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    Default Re: What if... (IR emitter modifications/tweaks)

    Quote Originally Posted by Eloi View Post
    One thing I don't understand : do the laser always use the
    same window time frame ?

    The same window frame either the target is @ 200' or 1000' ?

    My theory is that the laser shoots
    his first burst then wait for the return before
    sending the next and so on , untill it computes
    the change in distance over +- 40 burst.

    Could it be so simple that the only move the
    jammer has to do is interpreting the pulse rate
    of the laser and shoot at the same frequency ???

    Will I pass my jam exam Porfessor Jim ?
    Since light travels at around 1 foot per nanosecond: at 200 feet = window is 400 nanoseconds, and at 1000 feet = window is 2000 nanoseconds, which is the "time of flight" from the gun to the target and back. The window gets smaller and smaller as you get closer to the gun, and the jammer also sees the window occuring "sooner" in the pulse train.

    So for reference, consider a ProLaser III @ 200pps, which sends out one pulse 5000000 nanoseconds. Since the time window is 2000n nanoseconds at 1000 feet, the laser gun will only accept pulses .04 % of the time at 1000 feet, and this gets less and less closer to the gun.

    So, jammers can (and do) calculate a time window and then initiate a jamming sequence that is good for several pulses and makes it into the window. But, ultimately the jammer must continue to monitor incoming pulses and calculate the time window as you approach (or move away from) the gun.

    And in reality, it gets even more complex: I have been told (but have not verified) that some guns are smart enough to predict (based on the past pulses) when the next reflected pulse is likely to be received back, and then reject any pulses which are outside of that specific range. In this case, the window could be much smaller.

    Hope this answers the questions

  10. #10
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    Default Re: What if... (IR emitter modifications/tweaks)

    Quote Originally Posted by jimbonzzz View Post
    Since light travels at around 1 foot per nanosecond: at 200 feet = window is 400 nanoseconds, and at 1000 feet = window is 2000 nanoseconds, which is the "time of flight" from the gun to the target and back. The window gets smaller and smaller as you get closer to the gun, and the jammer also sees the window occuring "sooner" in the pulse train.

    So for reference, consider a ProLaser III @ 200pps, which sends out one pulse 5000000 nanoseconds. Since the time window is 2000n nanoseconds at 1000 feet, the laser gun will only accept pulses .04 % of the time at 1000 feet, and this gets less and less closer to the gun.

    So, jammers can (and do) calculate a time window and then initiate a jamming sequence that is good for several pulses and makes it into the window. But, ultimately the jammer must continue to monitor incoming pulses and calculate the time window as you approach (or move away from) the gun.

    And in reality, it gets even more complex: I have been told (but have not verified) that some guns are smart enough to predict (based on the past pulses) when the next reflected pulse is likely to be received back, and then reject any pulses which are outside of that specific range. In this case, the window could be much smaller.

    Hope this answers the questions

 

 

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