Last year it was no lasers, this year it's also no soldering. This is how hacker cons die. #34c3pic.twitter.com/n8Ep3BQ6Px
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Huh, actually on the 33c3 in the upper levels of the CCH there were a few high powered lasers, with a static beam configuration, also leaving the premises, which made me kind of nervous. If you can see a red laser beam without fog it's certainly beyond class-3a
Laser classes are useless. The danger posed by a laser is way more complicated than what class it is. Any useful scanner is going to be Class 4 (mine is), but there's a huge difference between a laser pointer (static beam) and a scanner at a minimum distance.
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For example, a scanner projecting a 1m diameter circle (quite a simple pattern) will only deliver about 1/400th the energy to a human eye that the same laser running CW as a static beam would. It goes lower with more complex patterns and wider beams and larger projection widths.
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I'm very happy to use my projector taking basic security precautions (point it at a wall, keep people away from the area between it and the wall), but I also own (not by choice) a 1W pointer and I don't dare turn it on without wearing goggles, because that thing is *nasty*.
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Laser classes are to give a quick impression of how to (not) look at it (pun intended). Class-1: Could be a friggin death-star inside, but everything is safely contained within the device. Class-2: Laser leaves the device but is eye safe even on direct exposure.
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Yes, Class 1 and 2 are useful for consumer devices, but the class system is basically useless for devices *intended* to emit laser beams beyond a 1mW laser pointer.
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Class-3: Will cause eye damage. Class-4: Will set shit on fire. There are also subclasses. Most important for laser projectors: 3a vs 3b vs 3c. 3a is: Eye damage on direct exposure. 3b: Scattering off polished surfaces cause damage. 3c: Scattering off dull surfaces cause damage.
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Class 3 and 4 and their subclasses are all but useless. The actual result depends way too much on the specific circumstances. Obviously my class 4 laser projector neither sets shit on fire nor is harmful when scattered off a dull surface.
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Then there's the topic of scanned vs. non-scanned. And unfortunately there's only very little research happening on that. Some of which is done at a institute which is kind of next door to my lab.
Thanks. Twitter will use this to make your timeline better. UndoUndo
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Here's the thing: In the research we do at our group, we deliberately deliver a focused laser beam into a subjects eye (usually ourself), to create volumetric images. We are using scanning spots, but we don't take that as a reason to go over class 2a; we keep it safe for static.
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Well duh. Class 2a is already ridiculously bright when aimed into an eye directly. If you're focusing all the energy directly into someone's pupil, of course you don't need to go to dangerous energy levels. There is an enormous loss in diffuse scattering that you bypass.
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