License tag/plate cameras are in wide use in security, toll collection and traffic infraction prevention systems. Snow can degrade performance. This device uses an energetic infrared laser device directed by some spiffy xpatch like control system to melt snow from license plates.

This system is cost-effective when there ratio of cars to cameras is very high. When the ratio of cars to cameras is very low, consider Heated License Plates (below).
-- husband_of_bath, Dec 08 2007

Heated License Plates Heated_20License_20Plates
Lest we forget [husband_of_bath, Dec 08 2007]

I could see this as a device in action movies. [+]
-- Spacecoyote, Dec 08 2007


Did you think about this? OK, suppose there are 100g of snow on the licence plate, and suppose that you need to melt this in half a second (as a car drives past).

The latent heat of fusion of ice is about 335J per gram, so you need to deliver about 33,500 Joules of energy in half a second (this assumes that the snow is already close to its melting point). This means that you have to deliver about 67kW of heat to the licence plate. So, you are going to be wielding a 67kW continuous-mode laser, aimed by a "spiffy" system, amidst moving traffic.
-- MaxwellBuchanan, Dec 09 2007


//This means that you have to deliver about 67kW of heat to the licence plate. So, you are going to be wielding a 67kW continuous-mose laser, aimed by a "spiffy" system, amidst moving traffic.//

Wicked Cool!
-- jhomrighaus, Dec 09 2007


category?
-- pertinax, Dec 10 2007


[-]

Had this been a licence plate snow generator, on the other hand...
-- Ned_Ludd, Dec 10 2007


100 grams of snow on a license plate? I guess I wouldn't really know, as I can still wear a sweater outside, and need short sleeves on in the afternoon, but how does a tenth of a kilo get stuck on a primarily vertical surface?
-- ye_river_xiv, Dec 10 2007


What could possibly go wrong?
-- marklar, Dec 10 2007


//100 grams of snow on a license plate?// That's four ounces, or enough for a modest snowball. Feel free to assume 50g, requiring only a 34kW laser.
-- MaxwellBuchanan, Dec 10 2007


Sounds like it would be easier to use a snow penetrating radar to read the shape of the number thru the snow.

Does everyone use raised letters on their license plates or is that just in the states?
-- MisterQED, Dec 11 2007


Number plates in UK used to have raised characters. Now, they're smooth - black letters and numbers on a white (front) or yellow (rear) reflective surface, with a clear top layer. They're quite expensive, but we don't often need to buy them as the number stays with a car for life (unless an owner changes to a 'vanity' plate, or it's re-registered for some other reason).
-- angel, Dec 11 2007


Seeing how I dearly detest traffic cameras - I found the destroyed Gatso website amusing and disturbingly compelling - the last thing in the universe I want mounted on these things is a HEAT RAY.

But if I could have one on my car aimed back at the camera, that's another matter.
-- elhigh, Dec 11 2007


//But if I could have one on my car aimed back at the camera, that's another matter.//

Mirror.
-- MaxwellBuchanan, Dec 11 2007


The mirror isn't as fun as actually getting to aim and fire the GatsoBlaster for myself. But it is more defensible in that it is a passive device.
-- elhigh, Dec 12 2007



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