SV: oops... (was Re: Nology)

[Mos]

On Sat, 2 Jan 1999, Roland Johansson wrote:

M>First it didn't show up in my mind but when thinking of this
M>idea a drawback appeared to me. All the welding helmets I been
M>looking thruu (two) are having a big green filter, looks like
M>that might be a problem. But why not have a LCD showing the
M>plate number and turning it off when a flash appear?

Because an LCD panel does not consitute a legal number plate. If you get
pulled over for anything, I'm sure it wouldn't be too hard to work out
something funny is happening. I very much doubt an LCD panel showing the
numbers would be convincing. Also the welding mask LCD panels turn opaque 
entirely. You would need to obtain an LCD panel that has individual
sections in it to make up the differnet numbers and letters. 
In Australia you are allowed to have clear plastic number plate covers,
hence an LCD panel can be made to look like one of those.

Cheers, Mos.

M>Hm, have to go to my fathers house and make a close examination
M>of his helmet in the evening
M>
M>
M>
M>Roland Johansson
M>Scirocco 1,6l TIC -82
M>> >I like your idea of an LCD screen similar to the expensive
M>welding hoods. The
M>> >opaquing action would not have to outrun the light, only go
M>dark before the
M>> >camera lens had collected sufficient light. Anybody know the
M>shutter speed
M>> >used?
M>> 
M>> There are two sources of light used to expose the film. First
M>is the flash
M>> from the speed camera, the second is the ambient light hanging
M>around. The
M>> shutter speed is likely to be around 1/125 to 1/250 of a
M>second, certainly no
M>> faster than 1/500. Camera flahes have very short durations. I
M>don't know how
M>> quickly the light builds up from the flash, but any trigger
M>circuit would need
M>> to detect the flash building up and get the LCD opaque before
M>enough light had
M>> arived.
M>> 
M>> The effect of the ambient light would be interesting, since
M>this light is
M>> always there, and the flash is triggered somewhere in the
M>middle of the
M>> exposure. The shutter opens fully, then the flash fires, and
M>the shutter
M>> closes. Depending on the power of the flash and the distance
M>from the camera
M>> to the car, ambient light would probably have no real effect
M>on the image.
M>> 
M>> --
M>> Tom Parker - tparker at nznet.gen.nz
M>>            - http://www.geocities.com/MotorCity/Track/8381/
M>

--
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|           Jealousy is a lifelong curse...          |
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| Lukasz Szymanski,                       /\/\OSFET  |
| 3rd Yr, BE(Comp)/MBiomedE                       |--+
| The University of New South Wales            __||<-+
| Email: s2193387 at cse.unsw.edu.au                 |--|
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