Wanting to test home built lidar jammer

[mb300sd]

Rather than having heads, how about having many strips consisting of a few LEDs mounted all over the grill, in the headlights, turn signals, around the windshield, basically every possable place on the car, so that the entire car becomes one huge IR emitter?

[Lucky225]

Rather than having heads, how about having many strips consisting of a few LEDs mounted all over the grill, in the headlights, turn signals, around the windshield, basically every possable place on the car, so that the entire car becomes one huge IR emitter?

Now were thinking outside the box

[Solion]

Right at the moment it is a crawl before we can walk sort of issue. First thing is proof of concept of using off board jamming heads, then if that works we will look at the offboard units to fit inside the headlight housings and markers. Then rows along the lower edge of the windshield/side view mirrors.

So thats where we are at the moment. second test of the new jamming heads will tell if this is going to be feasable.

[kpatz]

Project's looking good there Solion!

The biggest potential issue I see is: when dealing with narrow pulses, wire length becomes more critical. Longer wires will make the pulses less "sharp" due to the inherent capacitance of the wires. There could be a tiny amount of propagation delay, and response delay in the LEDs (how long between the LED receiving current and it reaching full brightness?), once again due to capacitance.

This is why Blinder and other jammer makers use compact heads with everything from the pulse generator to the driver to the LEDs/diodes all integrated, to minimize the effects of capacitance, and also to reduce cost and make installation easier. Otherwise, spreading the LEDs out over the whole front of the car becomes more practical.

[mb300sd]

Project's looking good there Solion!

The biggest potential issue I see is: when dealing with narrow pulses, wire length becomes more critical. Longer wires will make the pulses less "sharp" due to the inherent capacitance of the wires. There could be a tiny amount of propagation delay, and response delay in the LEDs (how long between the LED receiving current and it reaching full brightness?), once again due to capacitance.

This is why Blinder and other jammer makers use compact heads with everything from the pulse generator to the driver to the LEDs/diodes all integrated, to minimize the effects of capacitance, and also to reduce cost and make installation easier. Otherwise, spreading the LEDs out over the whole front of the car becomes more practical.

Is it really that much of an issue though? Especially if their wired in a star structure with wire lenth limited to a few feet. I can see it being an issue at MHz or even KHz ranges, but not really at the ~200Hz that the guns pulse at.

[22349cvc]

Rather than having heads, how about having many strips consisting of a few LEDs mounted all over the grill, in the headlights, turn signals, around the windshield, basically every possable place on the car, so that the entire car becomes one huge IR emitter?

I'd like some custom heads that mount to my H2 brushguard in place of the off-road lights...

[fulcrum]

Project's looking good there Solion!

The biggest potential issue I see is: when dealing with narrow pulses, wire length becomes more critical. Longer wires will make the pulses less "sharp" due to the inherent capacitance of the wires. There could be a tiny amount of propagation delay, and response delay in the LEDs (how long between the LED receiving current and it reaching full brightness?), once again due to capacitance.

This is why Blinder and other jammer makers use compact heads with everything from the pulse generator to the driver to the LEDs/diodes all integrated, to minimize the effects of capacitance, and also to reduce cost and make installation easier. Otherwise, spreading the LEDs out over the whole front of the car becomes more practical.

Is it really that much of an issue though? Especially if their wired in a star structure with wire lenth limited to a few feet. I can see it being an issue at MHz or even KHz ranges, but not really at the ~200Hz that the guns pulse at.

Yes, this will prove to be THE major issue. The 200Hz is not a problem, but switching the LED's in a few nano seconds is impossible with that type of wiring.

Trust me, this project will fail if you don't solve this. The specs of the LED's used only show you how fast you could pulse the LED using the ideal driver circuit.

If you want to use a long cable between LED(s) and driver, you have to make sure the impedance of the cable used matches the group of LEDs and the driver circuit. If not you will loose the energy in the transmission through the cable and the pulse shape on the LED side will not be a short, sharp pulse but a sort very weak sinoid shape.

For the same reason you use a coaxial cable to connect a TV to an antenna. 60 ohm is the impedance of the cable and that matches the impedance of the antenna and the receiver circuit of the TV set.

Do not confuse the pulse frequency (200Hz) with the pulse length. (30ns) Because that is in the multi MHz range.

[speed-dreams]

X2^

[The Chariot]

Also, not just pulse length and frequency, but start time delay, since you're trying to precisely time when the flash starts in order to properly fool the gun. Considering that the gun is measuring differences in the ns range, timing is critical.

[Eloi]

I can assure you the Blinder's driver are directly imbedded
in the heads , meaning the jamming signal
does not travel
thru the connecting wire(from the control box).
The wires serve only
to power the heads and sending back the signal
of actual jamming
for the visual and audio alert.

This info does not help you in the project
but let you realise that the whole process
of jamming can take place without a control
box.

I dont know for the other brand.