Laser detector (tech discussion)

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Kompete

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With ref to this thread http://mybroadband.co.za/vb/showthr...ctor-Mobile-Speed-Camera-Band?highlight=radar - and without having to discuss the ethics of the tech (we know its not illegal) - I am looking for a (speedtrap) laser detecting device that requires no wiring/installation. I there something like this?

I saw the Cobra XRS in the thread http://www.autostyle.co.za/prodview...ser jammers&cid=&pg=1&showall=&brandstr=&str= ; but I'm not sure exactly how it gets installed - seems like laying of wires is required?
 
Kompete said:
:confused:
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A laser detector will warn you that there is a laser in operation thus providing you with a oppertunity to slow down (hopefully soon enough) while a jammer disrupts the laser signal and could be treated as "defeating the ends of justice", is that clearer now?
 
supersunbird said:
A laser detector will warn you that there is a laser in operation thus providing you with a oppertunity to slow down (hopefully soon enough) while a jammer disrupts the laser signal and could be treated as "defeating the ends of justice", is that clearer now?
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OMG - did you even read the original post?

Let me repeat: I am looking for a (speedtrap) laser detecting device that requires no wiring/installation. I there something like this?
 
Kompete said:
lol, :D apology accepted.

Have you tried any detector device? and if so which one?
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Nope sorry, I stick to the speed limit or take my chances. Only cost me R300 this year so far, not worth investing in something like that... if its over R2600 it will take at least 8.6 years to pay itself off at the current rate of fines I recieve.

I'm sure it will require wires for power, the only way you could bypass that is for it to have its own 12v battery (which will make it bulky). Why the no wires requirement? If we know that we might find a solution.
 
supersunbird said:
Nope sorry, I stick to the speed limit or take my chances. Only cost me R300 this year so far, not worth investing in something like that... if its over R2600 it will take at least 8.6 years to pay itself off at the current rate of fines I recieve.

I'm sure it will require wires for power, the only way you could bypass that is for it to have its own 12v battery (which will make it bulky). Why the no wires requirement? If we know that we might find a solution.
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Sorry I wasnt clear about why 'no wires'. I was under the impression that some kind of detecting device needed to be installed in the front of the car (by the lights somewhere) and therefore wires to be layed from inside the car to outside. But I think i was mistaken.

Just sopke to the guys from lazerguys.co.za and they said the only wire is the power line which goes into the cigarette lighter and then the unit itself sits on you dashboard or mounted against the window with suction cups.

So looks like I can just buy it off the shelf and plug and play!

incidently there are cheaper ones too, like R800
 
Right, the engineer's method:

1) Simple googling reveals that's it's quite likely to be in the 904 nm wavelength range. (http://www.laserveil.com/laser/police/how-veil-fights-police-lidar/ , http://mr2.com/TEXT/FAQonLidar.html)
2) Simple physics will tell you that once you detect and react to the LIDAR, it's most likely too late (depending on how many samples the unit takes to determine your speed).
3) Only option would be then to block it, the trivial way by just emitting a large beam of 904 nm light. (Lots of diodes). (While I do know that mythbusters did this experiment, they never mentioned the wavelength of their diodes and the LIDAR, I'm guessing this is so because in they are in one of the least free countries in the world).

The result of 3 would mean that the LIDAR would give it improbable values (at best a speed of infinity at worst your actual speed if your diode power is too weak, LIDAR at 25 W = ouch!). Another option would be to try and reflect the near-infrared beam away or absorb it (difficult).
 
UnUnOctium said:
2) Simple physics will tell you that once you detect and react to the LIDAR, it's most likely too late (depending on how many samples the unit takes to determine your speed).
.
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At least you can then budget for the fine... :-P
 
Well what do you know: ooooooooooooooh

70 W, R500 a pop (at 905 nm though, 366.7 GHz off, but at that frequency, it's Q=0.0011 so it shouldn't be filtered out).

Otherwise, an array of these (half-intensity angle of only 30 degrees) phototransistors, a really sensitive op-amp and some form of lowpass filtering (analogue or a uC implementing an FIR) and you can have a good one. Damn, now I want to make one :/.

Anyone want to sponsor me making a prototype? You get first dibs on production models :D
 
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