PDA

View Full Version : Receiver for a jammer....



Vonkie
12-19-2005, 09:36 AM
Has anybody successfully constructed a laser receiver to trigger a jammer??

I was thinking of using a standard phototransistor with a sensitive pre-amp followed by a filter sharply tuned to 1.106 MHz (904 nSec) and a pulse extender for the trigger.

Will it work??

jimbonzzz
12-19-2005, 09:49 AM
As far as I know, most commercial units use a photodiode for detection. Specifically, many use the SFH203 (Osram) or one of it's variations, usually including a spectral filter. Something to look into...

Jim

Vonkie
12-20-2005, 10:04 PM
Nobody on the forum ever tried this??? :(

Can't believe it ... :shock:

truemagellen
12-26-2005, 12:33 PM
Nobody on the forum ever tried this??? :(

Can't believe it ... :shock:

I don't understand why you need it

laser jammers detect laser....and jam it

the receiver is built in to the design otherwise how would it recognize it

maybe I'm confused by your questions :?

Won Hunglo
12-26-2005, 03:42 PM
Nobody on the forum ever tried this??? :(

Can't believe it ... :shock:

Why would anyone want to put the time, effort & money into re-inventing the wheel?

Vonkie
12-27-2005, 01:27 AM
It is for a home built unit..... Forum project :wink:

As for reinventing the wheel, it may be so but I don't think so.. :?

BMW_525_TDS
01-01-2006, 03:44 PM
You need a photo diode, band-pass filter and a good op-amp..

band-pass should be from 70- 670 Hz (audio range).. :-)

In normal conditions you could use a circuit from graphic eq. (filter and op-amp) and with this filtered and amplified signal you should trigger a warning... :-)

Vonkie
01-02-2006, 01:46 AM
Wouldn't you need some kind of a pulse extender as well???
Just thinking of the short pulse received from the laser gun...... :(

drive-smart
01-02-2006, 09:50 AM
Almost missed this!LOL :D
On the Defender2 in-car box there is a socket to plug in a slave Pulse Master.
This will set the jammer off if it gets a laser pulse hit.

jimbonzzz
01-02-2006, 10:13 AM
Wouldn't you need some kind of a pulse extender as well???
Just thinking of the short pulse received from the laser gun...... :(

I would like to know this too.
With some of the photo diodes I have tried, they are slower so they have extended the pulse naturally. But the SFH203 has a 5ns rise/fall time, I have not yet tried this one yet with a laser gun.

Vonkie
01-15-2006, 03:04 AM
Just an update, found 2 receiver circuits that seem to do the job. Will post them once they have been proven. Then the discriminator needs to be finalised....and of course the jammer circuit!!! :D

A few questions:

Will the LIDAR gun detect if the jammer responds to, say, in this manner - receives 2 or 3 pulses, determines the jamming sequence and sends it for say a period to cover 2 or 3 or....whatever LIDAR gun pulses. Then the sequence starts over again. If one can do it this way it will simplify things quite dramatically. Also, I think, the gun will not be able to display a jamming signal as it get some of its pulses back. But should not be adequate to be able to reach a solution :shock:

LED's seem more powerful than generally accepted :roll:
The ratings of LED's is for CW purposes, so if you pulse them the same as a laser diode things start to happen quite dramatically. Currently I am pulsing LED's on my test bench and they seem to be fine running directly from 12V without a ballast resistor!!!!! I want to determine where catastrophic failure occurs..... :( Anybody done this or has more info????

:D

jimbonzzz
01-15-2006, 04:47 AM
Just an update, found 2 receiver circuits that seem to do the job. Will post them once they have been proven. Then the discriminator needs to be finalised....and of course the jammer circuit!!! :D

A few questions:

Will the LIDAR gun detect if the jammer responds to, say, in this manner - receives 2 or 3 pulses, determines the jamming sequence and sends it for say a period to cover 2 or 3 or....whatever LIDAR gun pulses. Then the sequence starts over again. If one can do it this way it will simplify things quite dramatically. Also, I think, the gun will not be able to display a jamming signal as it get some of its pulses back. But should not be adequate to be able to reach a solution :shock:

From what I know the guns generally need to receive a series of consistent pulses to be able to display a speed (50+ pulses maybe). So I think that your idea might work to jam.

Keep us updated on what you find :D

Vonkie
01-15-2006, 10:33 PM
I'll post the receiver circuits currently under test. One is LM741 (http://www.geocities.com/wastegate999/lidar/jam_rec2.jpg) based and the other on the CA3140 (http://www.geocities.com/wastegate999/lidar/jam_rec1.jpg)

Both have filters to exclude daylight and minimize false alerts. Comments would be welcome though..... :wink:

411
01-16-2006, 10:18 PM
I don't know if it can help you .

I build a very basic trigger device that activates v-1 but not a m-20.

Take a led use for remote control 940 nm and plug it in place of the speaker , the voice/sound modulates the led and trigger the v-1 .
Probably the 940 is not strong enough in the 900 band to trigger m-20 ,since v-1 is ultra sensitive = it captures the overband .

http://img40.imageshack.us/img40/1820/ledinfrared7pe.th.jpg
So pump the volume :wink:

Vonkie
01-22-2006, 01:09 AM
I think the M-20 has a low pass filter built into it and maybe a pulse discriminator to look for the gun pps. You will need the Lidar gun simulator to trigger it. Another quick check is to use your TV remote control and see if it triggers. If it does then it will be an indiction of its susceptibilaty to false triggers.

No comments on the receiver circuits posted above by any body :?: :?:

Has anybody tried to trigger a jammer using the standard commercially available detectors (Escort, Whistler, Uniden, etc.). If one could, say, install a photodiode to monitor the laser detection LED on the unit which will then trigger the jammer. :wink:

You could have jammer heads at the front and rear and just run them simultaneously when you detect a signal. :P

Or maybe you could have a clip-on unit that fits to the underside of the detector with forward and rear firing diodes..... 8)

SmaartAasSaabr
01-22-2006, 05:10 PM
I don't know if it can help you .

I build a very basic trigger device that activates v-1 but not a m-20.

Take a led use for remote control 940 nm and plug it in place of the speaker , the voice/sound modulates the led and trigger the v-1 .
Probably the 940 is not strong enough in the 900 band to trigger m-20 ,since v-1 is ultra sensitive = it captures the overband .

http://img40.imageshack.us/img40/1820/ledinfrared7pe.th.jpg
So pump the volume :wink:

Hey 411, put the radio on Doc Mailloux and the Blinder will go crazy :lol: :lol:

SmaartAasSaabr
01-22-2006, 05:12 PM
Has anybody tried to trigger a jammer using the standard commercially available detectors (Escort, Whistler, Uniden, etc.). If one could, say, install a photodiode to monitor the laser detection LED on the unit which will then trigger the jammer. :wink:

You could have jammer heads at the front and rear and just run them simultaneously when you detect a signal. :P

Escortn ZR3 and Beltronics LaserPro 905 do that, when you hook up the Passport or Bel RD up to the jammer the laser sensor of the RD acts as an extra sensor. Of course there are also sensors that are built into the jammer too.

BMW_525_TDS
01-30-2006, 05:04 PM
What is band-pas in Op-amp?

PM-me if you need more info, i will be glead to help you.
Regarding the jamming technique you are going a good way....
Receiver looks like my first prototype!.. :-) good job...

In this stage you need more filtering and amplification, afther that you will ned some logic and cpu-ing to doo...

mrmichael112002
02-09-2006, 06:48 PM
Watchout - you get too close to someone's protected design...they'll bing up a lawsuit - or steal your name...hahahah

Vonkie
02-11-2006, 06:27 AM
Looking at the posting of 411radarlover made me think of something. :shock:

What will happen if you just modulate the jammer laser with pink or white noise??? :(

BMW_525_TDS
02-11-2006, 10:43 AM
nothing.. :-) will be filtered-out by lidar receiver....

ginasas
03-26-2006, 10:20 AM
Wouldn't you need some kind of a pulse extender as well???
Just thinking of the short pulse received from the laser gun...... :(

I would like to know this too.
With some of the photo diodes I have tried, they are slower so they have extended the pulse naturally. But the SFH203 has a 5ns rise/fall time, I have not yet tried this one yet with a laser gun.

Can you say, photodiode that have rise/fall time 100ns will react to laser pulse or he will think that no pulse? I don't have diode with 5ns at this moment.