LIDAR Jammer

Hardware incubation. See also our in development projects wiki.

Re: LIDAR Jammer

Postby ian » Sun Oct 07, 2012 10:51 am

Hi Jason,

Sorry you were greeted with politics. I'm happy to have you post any circuit here until someone tells me otherwise the flow of electronics represented is so dastardly as to be forbidden to represent in the physical realm. Then I'll make sure it applies to us in the US and our sever in Germany and then comply as needed.
User avatar
ian
Crew
Crew
 
Posts: 10578
Joined: Mon Jul 06, 2009 6:14 am

Re: LIDAR Jammer

Postby ian » Mon Oct 08, 2012 3:23 am

Ok, this got out of hand. I'm gonna zap it. Sorry I let it go. I understand there was some disagreement over the schematic, whatever, but it should never degrade to personal insults or attacks.
User avatar
ian
Crew
Crew
 
Posts: 10578
Joined: Mon Jul 06, 2009 6:14 am

Re: LIDAR Jammer

Postby hak8or » Sat Oct 27, 2012 3:08 pm

Hello Jason!

I have just found this project here in project development (so busy lately!) and I would like to say that the schematic itself looks nice, visually. I did not know that you can make an Altium schematic so good looking. :P

Anyways, how did you find such a high bandwidth led? I remember a few months back looking at LED data transmission using cheap off the shelf leds, but couldn't find anything that listed possible bandwidth of 1 Mhz or up. Also, I am confused as to how you are not killing the leds with so much current, even though the duration is only 83 ns. Did you get any dead leds? Also, any pictures, they are always welcome in threads! :)

And lastly, I did not see the original posts so I do not see the arguments made, but I would really like to chime in on this. While the legality of operating such a device on a vehicle is questionable in (I assume) many countries, the OP did not say he/she was going to use it on a vehicle. Maybe it was done out of curiosity, to see if such an implementation would work, which in turn could mean that it was meant to advance the OP's knowledge on the matter, and knowledge alone should never be impeded because of someones opinion on said knowledge. This project was not doing any harm to anyone, other than hurting the feelings of others through offense, so I don't see why it would have been needed to take it down. Just because information goes against your opinion or beliefs, does not mean the information should be blocked. Not to mention that if a police radar gun can be defeated so easily, then the guns were very poorly designed or planned out, showing a need to get a much more "secure" and "proper" means of measuring speed. After all, security through obscurity has never worked, is not working now, and never will work.

Thank you Ian for keeping such a project up, it is probably one of the many reasons this site is held in high regards among many hobbyists everywhere.
hak8or
Full Member
Full Member
 
Posts: 239
Joined: Mon Jun 06, 2011 11:06 pm

Re: LIDAR Jammer

Postby hak8or » Sun Nov 11, 2012 4:57 pm

Thank you for providing more information and an update!

Do you have any means of testing it if it actually works? Also, it seems that the bottom right text on the PCB is not etched fully, so I assume you made the board yourself? I also notice you have a Hong Kong coin, so does that mean you are based in Hong Kong? If you are, then are there not as easy ways to get PCB's for a reasonable price in small quantities, hence you etching the PCB yourself? Also, is there a specific reason you are sticking with a linear voltage regulator instead of a switching one? I assume to keep complexity low so you can have the project done quicker? It would have kept heat dissipation much lower though, going from 12v down to 5 volts at so much current.

Hopefully tests come out positive for this project! While a few members may have responded negatively, keep in mind that DP surely has a large amount of lurkers eagerly looking at your project. Again, thank you for updating! :)


Edit: woops, I re read and noticed that you said you ordered the PCB's, not made them, so excuse that quick lapse of thought. :P
hak8or
Full Member
Full Member
 
Posts: 239
Joined: Mon Jun 06, 2011 11:06 pm

Re: LIDAR Jammer

Postby sam512bb » Wed Dec 19, 2012 6:53 pm

jason wrote:Here's the completed jammer ready for mounting in my car (just in time for the holiday season when there is a lot more enforcement activity on the roads).

I measure an average current of 25 mA through each LED which is well under the 100 mA absolute maximum and corresponds to 250 mA of peak power given the 10% duty cycle on them. I could probably safely drive them even harder by using a smaller resistor but I don't want to do that until I've reduced the power dissipation of the 7805 further as it gets pretty warm to the touch with 15 volts on the input side.

Looking at the jammer with my IR-sensitive camcorder shows that the LEDs are extremely bright within their 20 degree beamwidth -- comparable to a 75-100 watt light bulb in terms of relative brightness on the display.

In the absence of anyone interested in doing formal testing with the unit, I'll be doing informal field testing myself over the months to come in combination with a Valentine One laser/radar detector and a V-8 pony car that likes to stretch its legs.

Image


Good day Jason,

Great work! As a suggestion, you may wish to change out your linear regulator to a switcher, as this will reduce the heat dissipation quite dramatically... With the liner regulator you are dropping 13.8v - 5 v, or 8.8V which is a hefty amount. I would suggest you look at the LM2675 switcher IC (+ inductor, diode, etc) by National (TI), or the self contained modules by TI (i.e. PT5101 series), etc.

Secondly, you may wish to place a larger cap (47uf or 100uf) on your 5V rail in order to provide some localized charge for the LEDs... 0.1 uf are pretty small and really meant to reduce switching noise, etc.

Cheers,

Sam
sam512bb
Jr. Member
Jr. Member
 
Posts: 65
Joined: Tue Dec 18, 2012 12:24 pm

Re: LIDAR Jammer

Postby southernduckie » Sat Dec 22, 2012 4:35 am

wow great work please keep us updated as to the results. I would assume that it would be possible to increase the number of leds just thinking of the distance a lidar can operate might need to be brighter? to be able to blind the reciever at 1000M?
southernduckie
Newbie
Newbie
 
Posts: 2
Joined: Sat Dec 22, 2012 2:56 am

Re: LIDAR Jammer

Postby arakis » Thu Dec 27, 2012 3:47 am

jason wrote:Hi Sam,

sam512bb wrote:Great work! As a suggestion, you may wish to change out your linear regulator to a switcher, as this will reduce the heat dissipation quite dramatically... With the liner regulator you are dropping 13.8v - 5 v, or 8.8V which is a hefty amount. I would suggest you look at the LM2675 switcher IC (+ inductor, diode, etc) by National (TI), or the self contained modules by TI (i.e. PT5101 series), etc.

Secondly, you may wish to place a larger cap (47uf or 100uf) on your 5V rail in order to provide some localized charge for the LEDs... 0.1 uf are pretty small and really meant to reduce switching noise, etc.


Happy Holidays and thank you for your ideas. Here are my thoughts:

The 7805 is dissipating 0.15(13.8-5) = 1.32 watts. Turns out this is well within the device's dissipation capability without a heat sink, and there is actually a small heat sink on the PC board. I ran it overnight sealed in the plastic case with 15V on the input side and it was fine in the morning. The choice of the 7805 in this project was predicated on simplicity and low cost. Thereanks was no requirement for efficiency (1.32 watts is lost in the noise in a motor vehicle). And even if heat were to become a problem, a $0.05 1-watt resistor of 10-20 ohms in series with the input power leads will safely move some of the power dissipation out of the 7805 leading to an even wider heat margin than currently exists.

The second change you suggest seems like it may any have some potential for bumping up the pulsed output power a bit. I will put my scope on the 5V rail and switch it on to see if there is any drooping occurring. Certainly the bandwidth of the 7805 is not sufficient to correct any IR droop caused when the IR LEDs are active so if this is more than 50mV or so, I'd consider it a worthwhile change. I believe a precise needed value of charge can be calculated, leading to a specific minimum value of capacitor, but the values you suggest seem reasonable at first glance.

Jason


Hi the 1.32W is right on the limit of it's capability.. at 65W/C that's 85.8C so you only have ~40C left for ambient temp.... but if the device is enclosed. We are then talking about at 100+C heater in an enclosed space, the air around it will heat up at over 40C even if ambient is 25C.... I use a rule of thumb of 1W for non heat-sunk to220... MHO only obviusly, but Id recomed at least getting one of those clip-on heat sinks...

I'd also place the LED-s in series and power them directly from the 12V battery, and control via a single FET...
best regards FIlip.
arakis
Crew
Crew
 
Posts: 1044
Joined: Wed May 25, 2011 11:15 am
Location: Belgrade, Serbia

Re: LIDAR Jammer

Postby ferdinandk » Sun Dec 30, 2012 4:48 pm

As you are switching a (relatively) large load very fast, things like parasitic inductance and ESR have be taken into account. I would try to bypass each LED with an 10 or 100nF ceramic cap. And maybe add another 100nF in parallel to the 47uF output cap, just to make sure.
ferdinandk
Newbie
Newbie
 
Posts: 28
Joined: Fri Apr 27, 2012 5:21 am
Location: Germany

Re: LIDAR Jammer

Postby madhawk » Sun Feb 10, 2013 5:35 pm

hello friends!

i have seen your post!
nice work!

i work since many years with laser jammer and radar detector (first customer and now i have my own business)

do you have testet your jammer?
i have 3 lidar guns and 2 of them are very very difficult to jamm!!!
(all guns have an jamm indicator.) when you take a "brute force jammer" you get a problem with the police because they can see over the jam indicator a jamming sequence from an laser jammer...
what you guys need is a intelligent jammer who can detect the guns and the true pps from the gan and send a signal with the same pps back to the gun.
my lti trucam has a antijam firmeware and the lidar gun change the pps and your jammer is knocked out...

when you need my help so i can make some tests with your device... (i am from austria!) or when you need other information about the lj´s on market please feel free to contact me.

i am searchin also a other device. i search a device who can read the bus protokol from an radar detector or laserjammer. (to build my own interface)
have anyone a idea?
thank you for your support
best regards from austria!
madhawk aka. RadarWetzi
madhawk
Newbie
Newbie
 
Posts: 1
Joined: Sun Feb 10, 2013 5:13 pm

Re: LIDAR Jammer

Postby traxonja » Thu May 30, 2013 3:01 am

Hello jason,

Any progress on this project? If you need an additional tester, I am willing to work with you in parallel.

Have you considered the detection of LIDAR pulses? It would be a good idea to receive the pulses from LIDAR and decide what to send out with your TX unit, as @madhawk suggested...

Best regards,
Trax
traxonja
Newbie
Newbie
 
Posts: 1
Joined: Thu May 30, 2013 2:58 am

Re: LIDAR Jammer

Postby handymandaveuk » Sat Nov 22, 2014 4:15 pm

I just found this Thread, interesting you guys are being Positive & getting motivated & trying to devise DIY Jammer systems. So many just want to get paid for testing them in US GOL RD etc.

It has to be said that considering the component cost of LI Laser Star whichever, running at $8-$10 they are grossly overpriced. I have done plenty of experiments and made many circuits. Some had very good range around 15+ Yards were triggering Laser Alerts, and would for Hours. That was an important step. It won't let me put the Url in to show you guys.

Some did give wacky Jam readings on guns -10Km/h etc, but earlier models probably were low on Grunt. That's sorted now. One had X4 high Gain Amplifiers and Pulsed 100 m/Amp led's at over double their 1.4Volt rating. To anticipate your next Question, no none fried even though emitters on all the time with Ignition. The fabled Lidatek LE-10 was a pure brute force Oscillator Laser Jammer and will still jam anything, interesting food for thought.

Anyone trying a Jammer must take a look at a Lidar Pulse, it's very low and high Amplitude, and this must be either imitated and returned (a'La LI L-Star , or obscured entirety, either method if done well=No reading.

Now I use the Osram 25W. See my You Tube Radtechdefence Britain. also DIY page with a few pointers. radar-laser-jammers with net
handymandaveuk
Newbie
Newbie
 
Posts: 1
Joined: Sat Nov 22, 2014 3:45 pm


Return to Project development, ideas, and suggestions