Cool I hope it works out for you :D
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Cool I hope it works out for you :D
Although I had considered delays in ns for the wire length I really did not see the need to worry about capacitance/impedance due to the fact the maximum wire length from jamming head, to transistor, to home made heads is now less than 3 feet.
Although I had to bust my ass abit to find a high speed switching transistor that could handle the current and would not significantly add to the on/off delays or screw the form up.
Sadly however my Old scope has gone to the great Ohm symbol in the sky and I wont be able to do a comparison of the forms from the led heart and the heads.
but now looking at it I am wondering if it is going to be enough. given that some jammers are throwing out 50w and above with pulsed laser diodes ...
we will see how this does ( if anything ) If it fails again I will take the next step of going from 3.6w per head to 30w per head with laser diodes. then to 100w
and so it goes
The key to successful laser jamming is finesse, not brute force.
Your return pulses don't have to be stronger than the gun's; in fact, they can be weaker. Consider that the gun has to read a reflected signal off your car, while your jammer heads are sending a signal direct to the gun.
So, before going crazy with lots of power, work on the timing of the pulses. Get yourself a nice high-bandwidth dual (or more) trace scope, so you can compare your head's pulses to those coming off the Blinder, and see how much delay/phase shift/loss you're getting through your wires/driver circuits.
I think this guy stole your idea:Quote:
Originally Posted by mb300sd
http://i47.tinypic.com/2rzt7br.jpg
:D
Here are the latest pictures of he new and improved jamming heads. I will be installing them tomorrow.
Designing and building a good jammer is not simple and, after the design phase, the task of transforming the prototype into a commercial unit comes with its own set of problems.
If you want to build your own jammer, then this is how I would design/build a prototype. (Just a rough list):
* Forget LEDs, and go for a pulse laser based design.
* Make the prototype modular.
- build a laser pulse unit in its own box with power supply etc. You connect this laser unit to your CPU unit using a coaxial cable with BNC connectors.
- build a laser pulse receiver unit, again in its own box with coaxial connector to the CPU unit.
- Build a CPU unit with the right interfaces to pulse transmitter, pulse receiver unit and development PC.
* If you want to cut some corners you might want to buy a complete pulse laser module, and concentrate on the receiver first.
A LIDAR jammer is a lot about timing the send and received laser pulses. You will have to measure the pulse interval of the laser gun as good as possible, and then you will have to insert your jamming pulse (again) at the right time.
Small time delays in hardware are not a problem as long as these delays are fixed.
An example of a fixed (hardware) delay is the time it takes between the pulse trigger of the CPU unit and the time the laser pulse unit actually sends out its IR pulse. (Hardware delays in the CPU unit, cable to the laser pulse unit, and the hardware of the pulse laser unit.) Because these delays do not change, they're easy to compensate for.
A more difficult type of delay is the one in the receiver. A wrong design will have different timing delays depending on the strength of the received laser gun pulse and/or the amount of interfering light. (daylight, headlights etc.) You really need a good design with the right components to minimize this problem. These receiver timing issues are very difficult to compensate for in software. Laserguns use avalange photodiode based receivers, expensive but ideal for precise timing. In a jammer 'normal' photo diodes are the logical choice.
Only when you have solved these issues it is time :) to create the software.
You can measure the time in the CPU unit in 3 different ways:
1: Using the stored energy in a capacitor to measure time. (Charge fast, and then discharge slow for timing resolution. This technique also works with slower CPU's)
2: Use an external (picoseconds resolution) timerchip that interfaces with the CPU. (This is how it's done in current laser guns as far as I know. Also works with slower CPU's)
3: Use the CPU internal timer to measure the pulses.
Assuming you go for option 3, then you will really need a fast (32bit) microcontroller. I think an around 100MHz 32bit RISC CPU is the minimum. ARM7 based controllers are probably the easiest choice. (There are many cheap development and prototype boards available based on this CPU family)
There are single chip controllers with enough speed, RAM, Flash, EEPROM, fast 32bit internal timers and input/output.
The ARM9 family is more powerful, but also more expensive and more complex to play around with. I don't have hands on experience with ARM9. I guess this might technically be the better choice, but maybe not for home-grown experiments. (Maybe I'm biased :) )
The CPU speed is important because this limits the resolution of the time measurements you can do with the processor.
Speed of light is around 1ft/ns, a 100 MHz CPU will give you a resolution of 10ft + bit errors. (This is why a 300MHz ARM9 based design can be better then a 100MHz CPU, because the timing resolution is 3x higher). Although a 32bit timer is not necessary for jamming, it will proof to be very handy if you want to sample laser gun and/or jammer output during the development phase.
Just for info. I did build my own jammer, and was able to jam my 2 different guns (Jenoptik LaserPatrol and LTI 100LR) reliable. This project crashed a few years ago on the laser receiver and lack of time. (My time) This jammer was supposed to double as a laser distance meter on a car. I couldn't get the resolution because of receiver timing errors combined with receiver sensitivity. (However the receiver was good enough for jamming purposes)
Avalanche :DQuote:
Originally Posted by fulcrum
As for everything else, it's all over my head..
Finally, someone has clarified this... if it were that easy as everyone thinks... we'd have our own homebuilt jammers...
I might convince some of my old co-workers to look into building their own.. Since all they do is work with lasers and optics..Quote:
Originally Posted by speed-dreams
I agree with the above.Quote:
Originally Posted by kpatz
For this you need an A/D system ie. Labview to collect data... a computer based ocilloscope...Quote:
Originally Posted by jigglyI agree with the above.Quote:
Originally Posted by kpatz
You stepping on snoopyc4's jurisdiction??? :eek:Quote:
Originally Posted by ATFAvalanche :DQuote:
Originally Posted by fulcrum
I would love to see those waterproof flexible "strip" LEDs used as jammer heads.Quote:
Originally Posted by Solion
http://www.oznium.com/product_photos/large/1850.jpg
They do make a version with IR LEDs, but the ones I saw emit at the wrong wavelength. :(
Just like the other poster said, you could turn your bumpers, your A-pillars, your roofline, and a whole bunch of other parts of your car into a gigantic jammer head. :lol:
This thread is epic... hopefully it wont be an epic fail :D
this is where I am at with a home made jammer in the overall,
The first thing is to see if Offboard heads will work with the blinder unit I have now. If I can make these heads jam effectively then the plan would be to see how many other places I could install heads, Then the attempt to increase the number of sensors in the unit.
Al of those things will lead me to the next phase of the "home built jammer " portion of this
Basically the original plan was to build a jammer on the cheap/something a hobbyist could build, Now after pulling all the information into play I see that there really is only one way to do this. But it means throwing jam codes. Here is what I suspect the final build will look like.
The Budget jammer
Hacked, 1 whistler radar/lidar detector , sealed in project box with apeture window with lens focused on the laser detector with pigtailed detectors on marker lights /grill/ wherever.
This would fire the jammer, 2khz pulse jammer with high output laser diodes or leds that will will run on a timer then shut down. /or can be turned off
Yeah , will you throw a jam code? probly , well for PL3 it doesn't matter. but it will be fun to test. Simple build almost anyone could construct in a couple of evenings. for about 50.00.
mmmm I don't know what snoopy's job is :D care to enlighten me?Quote:
Originally Posted by swargaYou stepping on snoopyc4's jurisdiction??? :eek:Quote:
Originally Posted by ATFAvalanche :DQuote:
Originally Posted by fulcrum
I just know what APD's are from work.
Well we live and learn and build better. After taking the switching rig to a friend of mines scope we are ditching the HS transistor setup for driving the new jammer heads. The wave forms are not there for what I think will work.
Enter the MOSFET driver... Yeah .. Now were talking.
Stay tuned.
Good decision, I'm sure a MOSFET is the best component today to drive those LEDs. These modern MOSFETS are even fast enough to drive a pulse laser to full power within a few ns. But even the fastest MOSFET can not drive a large group of LEDs with some (long) wiring fast enough for your purpose. (Why do you think blinder uses 1 MOSFET per LED, and then mounted very close to that LED)Quote:
Originally Posted by Solion
Of course it's a fun hobby, but I'm pretty sure that you are wasting time and money now. Why not design a driver layout that will work, and integrate that with the LEDs in a single compact unit?
Quote:
Originally Posted by fulcrumGood decision, I'm sure a MOSFET is the best component today to drive those LEDs. These modern MOSFETS are even fast enough to drive a pulse laser to full power within a few ns. But even the fastest MOSFET can not drive a large group of LEDs with some (long) wiring fast enough for your purpose. (Why do you think blinder uses 1 MOSFET per LED, and then mounted very close to that LED)Quote:
Originally Posted by Solion
Of course it's a fun hobby, but I'm pretty sure that you are wasting time and money now. Why not design a driver layout that will work, and integrate that with the LEDs in a single compact unit?
Well we will see, I have now shortened the leads to the absolute minimum 1.5 feet in total. and the new fet driver is giving me really clean pulses. SO going to do a single run test and see of the offboard heads work
we will see
Mosfet driver with heatsink in place. If its going to work, this may have the best chance at it.
Will be sealing it in the same plastic as the heads for waterproofing. At a possible 20 amps the heatsink will be very necessary
Looking Good!
x222222222222Quote:
Originally Posted by STiMULi
Hi,
I stumbled upon your ideas through googling for laser jammer home brew info.
I have read 95% of this home brew thread and I love what i read. keep it up.
Can I suggest a few items for you to look at.
go to worlwideweb dot amazing1 d0t c0m forward slash infrared-lasers
and search for 904 nm diodes.
They have the wattage of 904nm diodes in you favourite flavour, and a pulsed 904nm 10watt premade device..:D.:D.:D
I'll be following your findings and add what i can to help out. Keep up the great work.
happy frying :o
FN
Here is the latest video of the new and improved jammer heads hooked to the old blinder. If there is a chance this will work , I really think that this is going to be it. If not then I will go to the 2khz square wave circuit and see if it jams. regardless the heads and driver are there to stay,
This is running them at 8 amps . second to the lowest setting on the CC driver
rated at 100 ma each , I am now running them at 200 ma each pulsed. I think I will probly be safe all the way up to 650 ma each
[ame=http://www.youtube.com/watch?v=xfh0xDpfPFk]YouTube - REC-00008.avi[/ame]
here is a video of the daylight testing.
[ame]http://www.youtube.com/watch?v=-nKw_Yp0bWk&feature=player_embedded[/ame]
Quote:
Originally Posted by Solion
Looks like the one on the right is a little weak
No, it is exactly the same, just the camera is very close to the car and pointed directly at the head on the left.Quote:
Originally Posted by Lucky225Quote:
Originally Posted by Solion
Looks like the one on the right is a little weak
That is great looking!
Call it the TriClops!
lawl I can't wait to see this baby in action.Quote:
Originally Posted by STiMULi
Well I hope it works with the Blinder as an offboard head system that can be added to out of warranty (or broken ) heads units. If this doesnt jam, then we will go with the 2KHZ jam unit and detector.Quote:
Originally Posted by Lucky225lawl I can't wait to see this baby in action.Quote:
Originally Posted by STiMULi
But, as I side note, we do have SOMETHING happening, Dont know exactly what it means but.... We have a red light camera system here on windy hill. this was the first night I was able to pull up to the balk line. Now normally , my laser detector on the Bel goes off and continues to go off at the same time. the blinder head and the Bel 965 is BEEEeeeeeeeeeeeeeeeeeeeeee. it does this till the light turns green.
But tonight, (made 2 runs to be sure) Blinder goes off Beeeeeeeee, then Off. the 965 goes quiet as well .. then Beeeeeeeeeeee, then quiet, then beeeeeeeeeeeeee. it did this till the light turned green, about 5 -7 second intervals. it has never ever done this in the 2 years this thing has been in place.
I turned around and went and did it from the other direction. Exact same response , just faster . on/off/on/off , the bell responding exactly the same.
Whatta weird year this is gonna be.
here are a couple of pictures of the 2 KHZ square wave unit I made , nice thing about this simple design is that simply by changing one cap in it I can have anything from 10 hz to 10khz pulse rate to feed into the led driver. so I can do some experimentation with it
this friday I am going to meet with Cat4 to test the offboarding of the blinder, and since everything is now socket related I can just plug this little baby in to see if the heads jam at various pulse rates (but we will begin with 2 khz )
I gather that your pulse generator is a resistor-capacitor timing circuit with the TO-92's handling swiching duties to trigger the jammer (er, excuse me, transponder) and I'm wondering why not use a 555 or 556?
I use them a fair bit to make adjustable PWM type circuits; by using a 556 I can have one section generating a frequency that is adjustable via a pot which feeds into the trigger on the second section which ouputs an adjustable pulse width also adjustable with a pot.
PS, Cool Project!
The premise is to make this as simple and easy a build as possible, Sadly Radio shack is not the store it once was and getting ahold of a 555 timers and such tends to put people off , But I do see your point.
But yeah , this is just a pair of 2n4401's with a third to give me my negative pulse to pull down the FET. This unit is the home made JAm -- Um , transponder portion of the system. I will be testing tomorrow to see if a 2khz pulse rate will jam with the heads I built. so there are two sides to this first, can offboard heads be added to a blinder, and second will the 2khz square wave generator jam a gun with the heads I built.
If the 2khz generator works, I will be connecting it to a elcheapo radar/laser detector. I hacked the LASER LED inside it to drive a transistor to flip the square wave generator on.
All in all. for about 40.00 you can build the Ja...transponder portion of this with the IR leds
Do I expect it to throw a jam code on some guns? Probly. But if you are smart and slow, then shutdown the Jtransponderand allow them to hit you , then it may be an elcheapo way to help save your ass.
we will know tomorrow if this has all been in vain or not
They don't sell 555s at ratshack any more?
sadly not , you can buy them online through their website. but not in most stores.
It has become an electronics store with parts as a sideline . FRYs however, mmmmm parts heaven
TEST RESULTS OF THE HOME MADE LIDAR JA_,TRANSPONDER
Well Cat4 was kind enough to put up with me and my mad science today in the not so wonderful weather, However we did get a break for abit, a respite from the rain to test 2 things...
First the offboard heads driven by a blinder unit. to be frank, given all that was said here I was not expecting much from this setup. Timings being as crucial as they are for a successful ja---transponder interferance. all I could do was hope. However..against the PLIII the blinder driven offboard heads punch through only happened at about 328 feet ( if I am wrong Cat4 will correct me) this is a significant step forward since the last test (since the last test was such an epic fail anything would be better) On this side of things I may adjust the power output to the leds, such low rates are just not getting them lit bright enough. But the viability of offboard heads seems plausible at least and worth looking into.
Now for the other side of things..... The home made Transponder . this is a square wave generator driving the FET unit used by the blinder test. that when fired by a elcheapo laser detector will transponderize a gun. my starting rate was 2 khz... and the result?
EPIC FAIL!!!... thats right, 2khz right to the leds = epic fail Like there wasn't even any jamming at all. max range punch through... However , Undaunted I had brought more than one frequency to drive the generator.. SO , I decided to go for broke. 90 KHZ it was the highest one I could drive for this test. So .. Shrug? why not ..
Aaannnddddd Drum roll please .... EPIC WIN!. punch through center mass at.. wait for it..
28 feet !! :eek:
Second run (just so I and Cat4 were not hallucinating) Headlight shot
128 feet!!:D
I went then and adjusted the led array to see if I could improve the headlight shot .. answer was ..... Feh 220 feet. I adjusted wrong ...:rolleyes:
I then swapped in a cap for 50khz just to see what would happen and adjusted the led array back into place ... the last shot was 28 feet again , but I don't know if the was a CM or headlight, Cat4 can tell us here this evening.
This is the way I remember it. If Cat4 says different Ill default to him as I am a giddy mad scientist at the moment. As for jam codes. this was just against the PL3 so no jam codes for that gun. but given the epic fail that was my previous attempt, this is a major improvement.
Now to tune this bugger UP! :D
I wanted to be the first to say congratulations!
very nice :)
Thanks , this has been a great bit of mad science fun and I am not done yet. with an offboard array there is no reason I cannot now build maker lamp arrays to fit my corner lights and even my headlights.Quote:
Originally Posted by The Chariot
I will continue to expand the array bit by bit till we are rock solid. and I may pump the rates up to 1-4 MHZ at some point But 50 and 90 khz worked well. One step at a time as they say. Will know allot more when we shoot other guns at it. can't wait till the end of the month to see the overall numbers at the frozen toes event
we will need a "mad scientist " column for our test results:D
very nice... now try to get a micro PIC or a RISC program it, find a Oscilloscope with a A/D system that collects data, and try to borrow the guns from somebody, and you'll have your own jammer ;)
HEH, well if I wanted a jammer that would not throw jam codes that would be a way to go. But most guns out there don't throw codes at all. this is a 40.00 build almost anyone with a soldering iron and a trip to ratshack could build (save for the vishay 890's from digikey)Quote:
Originally Posted by speed-dreams
It jams the PLIII. I wont consider this a complete success till we have done a few other guns. But as it is I am doing better than laser star with the PLIII,
The only guns I think I need to worry about is the laser Atlanta (of which I am told it will throw a jam code on headlights sometimes) and the Stalker.
The trafipatrol gun would be tough, But its in Europe only
I am going forward today and ordering more the the Vishay leds for the marker lights and the heads for the rear of the car.
At the end of the month there will be a full scale test across several guns I hope to be ready for it with a full loadout of Leds and various frequencies up to 4 mhz