BL> When they first started using cameras on the F4 I was tempted
 BL> to build my own flash unit.

 JT> You may be able to get away with it at night, but during the
 JT> day, the flash will have little or no effect on the exposure of
 JT> the photo.

  (grin) A photograph uses light reflected from the number plate, and
day or night this would be overwhelmed by the intense flash.

 JT> That and the pigs know that you are trying to defeat the thing.

  We are not dealing with rocket scientists. It would take them a week
to work out what happened, and by then you would be 100 miles gone.
And in any case, everything that is not proscribed is legal.

 JT> There was some discussion on the net about this, some guy had
 JT> come up with the idea of a light-operated infra-red flash.
 JT> There are a series of IR leds around your rego plate, and these
 JT> are supposed to flash on when the camera flash is triggered.
 JT> The intention being to over-expose and cloud the film around
 JT> the area of your rego plate. Personally I think that you would
 JT> need a huge abount of IR light to cloud any bloody film at that
 JT> distance let alone normal film.

  My idea was to install a "reversing" light and build the flash into
that (along with the reversing lamp). If the cops suspect, simply turn
it off.

 JT> Sensing the flash would still be a problem during the day,
 JT> would be very suseptable to false triggering, but since no-one
 JT> can see the infra-red flashes coming from your plate, this
 JT> would not be a problem. 

  Yes... this was what stopped me: high-beam from other cars at
night, and sunlight reflections during the day. My idea was to put the
sensor down a tube with a lens, to narrow the field of view off to
the side where the cops would be lurking... but I never tried it.

 JT> Another had come up with a more high-tech version of that
 JT> cardboard strip in the center of the rego plate, so if viewed
 JT> from an angle it covers part of your plate, this version is a
 JT> flat plate cover, and has the same effect of viewing an LCD
 JT> display at too far at an angle- you can't see it. 

  My fallback idea was black and yellow PVC tape to change the number.
I actually did this, and it's virtually undetectable unless they
actually look. 

 JT> Another guard against the laser "radars" is to
"steath" your
 JT> car against IR, so under normal light conditions, it seems
 JT> fine, but it severly reduces range of the IR laser, gives you
 JT> time to slow up. There was some talk of using another IR laser
 JT> to point back to the pigs, but the IR power required for this
 JT> may be excessive. As well as a wide enough angle to cover all
 JT> the possible positions of the pigs.

  That won't work. They lock to the fastest return in a set range, and
you's have to be phase/frequency locked to their signal or they'd 
just ignore it.

 JT> I've just had a thought on those lasers, could you get the pigs
 JT> for possible eye damage from the laser, or is the diffusion
 JT> angle too large for this to be a problem?

  ROFL! These are milliwatt lasers. The reason a laser works so well
is that you are tuned to the exact frequency, and the narrower the
band the less interference in that band... so you can use lower power
for the same range.

 JT> Either way, can't you have an IR sensor "led" on your car to
 JT> look for IR pulses? It may not guard you against it, but at
 JT> least you will have a chance to make a decision on what to do. 

  They outlawed radar detectors a few years ago... it's even illegal
to possess them (like drugs), but no one has tried flashing the
cameras yet. The response has to be quicker than the shutter, but it 
ought to be possible.

Regards,
Bob
___ Blue Wave/QWK v2.12
@EOT:

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