Wanting to test home built lidar jammer

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1) Threshold of sensitivity of a lidar gun to "see" its own pulse amongst noise generated by a high power jammer is limited.

This is supported by a well known and tested jammer called the LE-10. Firing at 2 mhz (or as high as 4 mhz) it put out an amazing level of IR, and was (still is) an effective jammer.

The LE10 (I have one, and played around with a lot) is a pulsed laser system, that jams the lasergun using high frequency pulsing instead of smart pulsing. (Jimbozz posted a good explanation of it sometime ago) Its output cannot be compared with your LED system, because you cannot get the switching times in the ns range as the LE10 can. The LE10 radiates very nice sharp ns range spikes, but at a very high pulse rate, these pulses enter the laser gun just as easy as its own reflected signal.

2)Lidar guns are not made to seriously beat jamming technology. A bold statement perhaps but really the only thing Lidar guns have really tried is to beat is sensing technology. weird rates that are not recognized or multiple pulses hidden with the pulse train. Or amplitude modulation. The guns sensing side even gated has limitations as to what it can do to try and filter for its own signal. Most guns claim a .3sec pull of the trigger to a speed reading. This does not allow a whole lot of time for in depth analysis of what it is getting back. And given the LE-10 can still jam the ever livin snot outta every gun on the planet regardless of jam code. I think proves the point.

The LE10 is so effective because (by design) it doesn't try to beat jamming detection. The other BIG difference is that this jammer uses a pulse laser, that can resist much higher pulse frequencies than the popular Osram pulse lasers. If you would pulse the Osram SPL-PL90 at 1MHz (fully using its 16Watt peak power), it would burn out almost instantly. (I think the datasheet specifies the limits of these lasers at 1000Hz @ 100ns pulses = 0.1% duty cycle)

I fully agree on your statement that much better anti jamming techniques could be used. If (for example) the pulses coming from the lasergun are timed randomly, then none of the current jammers (except LE10 type of jammers) could jam this type of lasergun.

I bet you still didn't read a lot about photo/pin diode receivers. There is no "in depth analysis" of what is getting back, because the noise doesn't reach the processor part of the gun in the first place. It is simply filtered out by the analog receiver circuit around the photodiode.


3) Lidar gun sensor saturation. I still contend that beyond filtering for noise that the lidars sensor can be simply overloaded. Unable to detect the small changes in the noise level and reflected pulse because it is balls to the wall pegged with so much IR in the correct bandwidth that it cannot pass any more current.

I connected a 300MHz oscilloscope to 2 different laserguns. (one of them was the LTI100) Trust me, you can saturate these receivers but you will never be able to do that with a few dozen of LEDs at 300-3000ft. This is exactly what i tried using a 50% mirror in front of the laser gun that was connected to the scope. I pointed the lasergun at a licenseplate at 300ft. while beaming infrared light into the gun via the 50% mirror. With other laser guns this might be easier to do.

My conclusion is that a few watts in the proper nm range at 2 MHZ can potentially Jam most guns, And can be done for under 100.00 (around 50 actually.

I really hope you prove me wrong.... but you have to test with different type of guns. The PLIII is not the right gun to test your system.


Overall I am not trying to build a unit that can prevent a jam code. But to be honest . Jam codes have been seen in guns when no jammer is present. And if you abide not to JTG it is not going to be a factor.

Only time will tell. This weekend will be very interesting as beyond the MOAC we will hopefully do just some standard testing against the various guns

I might have an idea for you, that will enable you to switch the LEDs fast, and make your jammer act as a LE10.

You want to modulate (or pulse) your LEDs with an 1 MHz or higher frequency signal. (basically switch them on and off 100% 1000000 per second) The problem is getting the energy into the LEDs at that frequency in a simple design.

Basically this is a radio transmittor at 1MHz of enough power, but with an array of LEDs connected to it instead of an antenna.

- The transmittor is easy. (1MHz generator connected to a high power opamp)
- Then (also easy) the "antenna" cable to your LEDs can be a simple 50ohm coax.

The remaining problem is a to create a LED-"antenna" that has an impedance of 50ohm at 1MHz. These impedances have to match, otherwise you will loose most of the energy as a result of transmission losses.

There are two possible solutions to this problem.

- Use a transformer to adapt the LED array impedance to the 50ohm coax.

or

- Connect the LEDs in such a way (combination of groups of serial and parallel connected LEDs) that the resulting group of LEDs has the needed 50ohm impedance at 1MHz.

I expect a transformer to be the practical solution to this problem.
If this idea works, then you have your cheap simple noise jammer.

http://www.nimbusworld.com/jPicts/Ba...oiseJammer.jpg
I don't think this will ever become a FCC approved design.....................

if you want to saturate a gun, with high frequency, you need a Osram diode not LED's... and you need a better circuitry to drive it as well ;)

I never realized how dumb I was until after reading the last few posts :p

quote :I bet you still didn't read a lot about photo/pin diode receivers. There is no "in depth analysis" of what is getting back, because the noise doesn't reach the processor part of the gun in the first place. It is simply filtered out by the analog receiver circuit around the photodiode.


I have read up on them as they are used for communication systems. However I would love to look at the circuit they are using in a Lidar gun. Again from what I have seen there is an absolute noise ceiling. In fact dare I say it could be jammed with CW. One of the reasons I don't think anyone has ever tried is that most people were told from the outset that hey would "fry their eyes" with the amount of power needed to do it. Just for fun I may try that with a couple spare heads from another build to see what happens.


Quote:I connected a 300MHz oscilloscope to 2 different laserguns. (one of them was the LTI100) Trust me, you can saturate these receivers but you will never be able to do that with a few dozen of LEDs at 300-3000ft. This is exactly what i tried using a 50% mirror in front of the laser gun that was connected to the scope. I pointed the lasergun at a licenseplate at 300ft. while beaming infrared light into the gun via the 50% mirror. With other laser guns this might be easier to do.

Well I tend to think however that given the amount of reflected energy from the laser to the pin diode that sensitivity is going to be quite high and even with cruddy waveforms the sheer power of what I am tossing out is going to drown out its ability to see what it wants to see. Take a look at your LEDs and then take a long look at the radiant intensity of mine

Yours http://www.nimbusworld.com/jPicts/SFH487.pdf and http://www.nimbusworld.com/jPicts/SFH459x.pdf

MINE : http://www.vishay.com/docs/81313/tshf5210.pdf

Everyone needs to take a long hard look at those numbers and realize when I say HULK SMASH .. I mean it.

And check out the angular displacement while you are at it for comparison.

I don't think we can even try and compare the power output of the heads you made with the ones I did. And on top of it mine are closer in nm to the guns sweet spot.

I am going to just have to wait and see what happens with the test at this point. There are a couple of things I am not
hinting on that I have done with the array's. If the test is successful then the world will know. if not I will try a different system.

I tend to keep all of my schematics out of sight till it works. But there is more than meets the eye with this. Why do I need coax when the driver can be built into the head?

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Originally Posted by Solion

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I tend to keep all of my schematics out of sight till it works. But there is more than meets the eye with this. Why do I need coax when the driver can be built into the head?

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:confused: Because in our earlier discussion about cable length etc. the driver electronics always was seperated from the LED unit. If you want those units seperate, then the connection between them becomes a very important component.......................
Your LEDs look great and you are right on that, the radiant intensity of those LEDs is impressive compared to the LEDs I had to use 4-5 years ago, and wavelength is also a lot closer to the optimum 904nm. I hope your tests will be succesful! Really!!

I like this thread! Good reading!


:popcorn:


Phil :dirol:

Well got back form the MOAC and I am sure everyone is wondering how well the HMLT did

Overall not too well, The MOAC is insane. your jammer heads are either facing the dirt , the road or the sky. and for a brute force jammer that's a special little hell. however it DID jam. so the question was why such a poor showing given the drastic difference between the earlier tests with the PLIII and the MOAC.

Well, when I designed the heads I went with the 10deg leds. This was to extend the output ranges as far as I could. In a word I was trying the narrow the beam for by best levels at distance. The cone of IR from them was pretty tight. So in short, Not pointed even reasonably at the gun? = PT

I was pretty dismayed unsure that this was the problem , Infact I was outright depressed. with the evening comming on I wanted to do some standard testing against the Stalker and LRB. But with so many coming out (and with some amazing results) there was not going to be any time

Then the man , Cat4 .. The master of all things Lidar let me borrow the Stalker.

I went back to the original place where we tested the PLIII and with a nervous twitch in my eye and a straight flat road we tested again.. I will have video tomorrow as it was getting a little too cold to hook up the video gear.

BUT after a little head adjustment, and tripod resting the Stalker like they did at the MOAC .. here were my numbers , at 25-30 MPH

CM was averaging be 70 - 90 feet PT
Headlight was averaging 120 - 180 PT

Now this is no excuse to do poorly on the MOAC, But I will have a rematch as I begin to combine LED's of greater deg cones out there. and seeing how cheap this can be built I will have a plehtora heads to stick into place with Velcro.

For right now for testing I HAVE THE PRECIOUS STALKER... THE PRECIOUS WILL BE PROTECTED!. HISSSSSSSSsssssssss

However YES , I can jam the Stalker with the present setup. Just not in MOAC maddness mode. And here is the strange shait... NO JAM CODES????let me know if there is a mode I need to put it in so it generates them.

But Cat 4, Thanks so much. really, It is the support of people like you that makes this ****ing fun as hell

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Originally Posted by fulcrum

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http://www.nimbusworld.com/jPicts/Ba...oiseJammer.jpg
I don't think this will ever become a FCC approved design.....................

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Why I failed physics...

As promised here is video of the HMLT working. sadly I had nobody to drive my car today to show the road test. So what I did in this case was under 100 foot static test against the range finding propertys of the Stalker gun.

Boy does driving 30 mph or higher really make a difference in jamming. However I think this does highlight that the underlying system is quite viable and can be cheaply built.

Enjoy! :D

[ame=http://www.youtube.com/watch?v=VWhrfK-qHrg]YouTube - Home made Lidar jammer test[/ame]

Now for MORE POWER

I love the sound of the Stalker firing.

It only takes a few pulses coming back to get a distance reading. Not even my LI's will keep me from getting a distance reading.

I love the sound of the Stalker firing.

It only takes a few pulses coming back to get a distance reading. Not even my LI's will keep me from getting a distance reading.

While you call the MOAC madness it did do what it was supposed to do and find the weakness in your system. I really think you need to simulate an overpass shot and see how that performs.

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Originally Posted by category4

I love the sound of the Stalker firing.

It only takes a few pulses coming back to get a distance reading. Not even my LI's will keep me from getting a distance reading.

While you call the MOAC madness it did do what it was supposed to do and find the weakness in your system. I really think you need to simulate an overpass shot and see how that performs.

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Oh I agree. it really showed that a narrow cone of fire is bad for that course. I did my research on the LI's they are firing at 25deg so there is quite abit more play in that setup.

I have some bar magnifiers on order I will be mounting in front of my main arrays to open up my angles. then I will retest. for a buck each if they work they will go on the man arrays horizontally and secondarys vertically

So overall from what you see there, am I going down the right path on my testing or am I making it way to hard on myself?. My goal right now is to make it unable to even get distance readings anywhere on the front of the car like you see in portions of the video. Or is that a near impossible task that will make me pull my hair out.

It only takes one or two pulse to get a distance reading, so I don't think you will ever be able to jam a distance reading completely.

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Originally Posted by category4

It only takes one or two pulse to get a distance reading, so I don't think you will ever be able to jam a distance reading completely.

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You are probly right, as it stands I get distance readings easily on the headlights, But I don't get Immediate PT till under 200 feet.

I am gong to have to get on the balcony of a friends house to test for overpass hits once I get the lenses on

New video of the jammer in use. better videos to follow . this is shooting down onto the car at an angle . my nice flat run had the landowners on it today )

[ame=http://www.youtube.com/watch?v=hak2Ckj4DTU]YouTube - output[/ame]

More room for improvement as the headlights need work.

great work man keep it up!!

Clearly on the right track. Excellent work! Very impressive! :thumb2:

I'm surprised it didn't trigger any jam codes...

After reading all of the most recent posts I have couple issues. (I had read all the way to the initial arguments about why you wouldn't be able to use LEDs over a month a go.)

1. Why does everyone use the same LEDs instead of mixing lower or higher values for better performance?

2. The only reason you aren't doing Laser Diodes is because of the price but you left out the price of the Blinder CPU you are using to do the tests. What for? That is no where near $50 worth of parts.

3. Do you think the IR based system would be better if it was active for example where the some of the heads tracked the incoming IR source not just stationary?

4. Do you think 8 laser diodes would be overkill for a front system?

5. If overpowering the gun is your preferred method (blinding) why don't you just make a strip that goes across the front of the car with say 80 IR LEDs? At some point won't the massive IR output prevent any external light from reaching its destination and reflecting? Don't most materials have a limit at which they stop reflecting?

6. I read something about you working on something like Veil. I want to try this but I am going to have to wait until I have access to a centrifuge. I am thinking I could use this info to make a coating that blocks all IR reflectivity that can be added to most car waxes or clear coats. It can also be applied to glass and plastics. What do you think?

I also learned about the electrical resistance caused by IR light in another patent. It would be cool to have abase coat that absorbed the IR or that could be modified by applying power like with an a LCD.

INFRARED SHIELDING FILTER - Patent application - with high heat resistance and transparency realizing an enhanced infrared shielding effect

Method and apparatus for measuring light reflectance absorption and or transmission - Patent 3910701

Very impressive, I am going to keep an eye out to see what happens with this.

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Originally Posted by Dead Aim

2. The only reason you aren't doing Laser Diodes is because of the price but you left out the price of the Blinder CPU you are using to do the tests. What for? That is no where near $50 worth of parts.

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The additional parts.

Where is the cheapest place to get 904nm laser diodes or IR LEDs in that range?

If anybody finds a source send me a PM.

jameco's got em for $40.

C'mon Solion. It's been a mighty long time since your last update. Did the MIB get to you? Did the black helicopters take you away? Threats? Bribery? Extortion? Waterboarding? Inquiring minds want to know. Out with it! :confused:
Apchar

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Originally Posted by apchar

C'mon Solion. It's been a mighty long time since your last update. Did the MIB get to you? Did the black helicopters take you away? Threats? Bribery? Extortion? Waterboarding? Inquiring minds want to know. Out with it! :confused:
Apchar

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No no no , just been busy and well... cant talk about a whole lot till everything paperwork wise is done. Believe me I want to tell you all the news , but cant even whisper what is coming.

All I can say is .. it will be worth the wait... I promise.

Egad. By your secretive demeanor we can all of this gathering safely assume you're going to attempt to patent your new prize. How do I divert you from this misery-laden path upon which you've set yourself. Patents are not the holy grail of capitalism as we've all been lead to believe. They are an arduous gauntlet of tedium, bureaucrats, and that most depraved and perverted species western civilization hath spawned: Orcs! er.. I mean lawyers.

Sorry. I just finished watching Lord of the Rings for the n'th time (n >> 1).
Honestly Solion. I was immersed in a patent-mongering atmosphere for 11 years. It is not what it was meant to be. Unless you're one of the big boys, it's hard to get a patent and damn near impossible to defend it.

But the quest before you is of your own making and we can wish you only good fortune ... Sorry.
God Speed young hobbit.
Apchar

Wow - last I checked this thread or the board was back in November. It is absolutely AMAZING to see the progress. Good job!Honestly, Ive been thinking about buying a jammer but this thread is the only reason I havent. You can say that youve sidelined me! Of course, if a jammer sensor head is still required, perhaps I should buy a system if anything for donor parts in the future.

Solder iron is warming up and ready to go....

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Originally Posted by tj90

Wow - last I checked this thread or the board was back in November. It is absolutely AMAZING to see the progress. Good job!Honestly, Ive been thinking about buying a jammer but this thread is the only reason I havent. You can say that youve sidelined me! Of course, if a jammer sensor head is still required, perhaps I should buy a system if anything for donor parts in the future.

Solder iron is warming up and ready to go....

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I don't think anyone's heard from the author in the past 20 or so days tho :eek::rolleyes:

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Originally Posted by Lucky225

Quote:

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Originally Posted by tj90

Wow - last I checked this thread or the board was back in November. It is absolutely AMAZING to see the progress. Good job!Honestly, Ive been thinking about buying a jammer but this thread is the only reason I havent. You can say that youve sidelined me! Of course, if a jammer sensor head is still required, perhaps I should buy a system if anything for donor parts in the future.

Solder iron is warming up and ready to go....

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I don't think anyone's heard from the author in the past 20 or so days tho :eek::rolleyes:

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You will, I think he's on to something!! Or on something.....:eek:

Actually I'm looking forward to seeing what he has in the works!!!

I wonder why hes so secretive.

If you don't mind lifting the cone of silence just a smidgen Solion I'm curious about something. What duty cycle are you pulsing your LED's at?

Why don't we let this drop? He's made it obvious he's not going to talk about it.

I am sorry guys, I just can't right now. Id say lock the thread until I can.

Solion

Solion has been up front the entire time. There is an issue that needs to be resolved I am sure.

Let it die... (I will)

:stop: