If laser graffiti replaces the Bat signal, I’m all for it. I can never see it through San Francisco fog anyway.

From the laser guy’s reply on YouTube:
———————————-
“…..i never heard about anybody to get blind from a laser so far. so i think ppl are smarter that you might think, and the can watch after them selfs ; )

of course, those so inclined can damage their retinas with dollar store 3mw units if they try hard enough

I suspect the maximum incident exposure in normal use (of the graffiti system) is much less than say the “harmless” laser dazzlers used every day on Iraqi civilians

a cleaning person working late at night struck in the eye by a transient bright light is not going to do their best to follow the beam

be more afraid of Russian trawlers

http://images.google.com/imgres?imgurl=http://www.uwmc.uwc.edu/political_science/MIIIE/ZM87blinding.jpg&imgrefurl=http://www.uwmc.uwc.edu/political_science/MIIIE/catalogMissilesC.htm&h=132&w=124&sz=3&hl=en&start=3&um=1&tbnid=SiRBGfiqkythvM:&tbnh=92&tbnw=86&prev=/images%3Fq%3Dchinese%2B%2Bzm87%2Bblinding%2Blaser%26svnum%3D10%26um%3D1%26hl%3Den%26safe%3Doff%26rls%3DGGGL,GGGL:2006-32,GGGL:en%26sa%3DN

http://thegayrecluse.com/2007/09/20/on-washington-heights/

This is clearly a plot, all you need to do is swap out your little decorative laser for a death ray and MELT THE BUILDING.

http://www.sensaa.com/es/laser-graffiti

Regards

However, if the scanning mechanism were to fail and the beam would come to rest stationary onto one’s eye… that *would* be a problem.

“why couldn’t you just use the projector and not bother with the laser, since it’s the projector that keeps the graffiti image on the wall?
morgenmeister (1 day ago) Show Hide Marked as spam
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cause you draw the pic with the laser. (cam tracks the green dot and then the projector follows)
and its about “direct interaction with the wall”
sounds gay, but i hope you get what i mean…

regards, f*”

I wouldn’t advocate testing that theory by looking out the window through a pair of binoculars though.

Second, to Michael Dean, I WOULD be willing to be in this building at any time this laser was playing on it, which is what we are talking about, right? Not gazing directly into a 30mw laser.

I do admit I had it wrong, I thought they were using the laser dispersed to actually make the letters, but I’ve worked with a lot more powerful lasers on a closer basis than this and my eye doctor tells me my eyes are perfect, except for the astigmatism and nearsightedness, which I’ve had since before lasers were actively available, anyway (1963?)

But, if you think is a REAL hazard, then perhaps we should ban all automobiles, except for emergency purpose use, because automobiles are the leading cause of accidental death. OMG!

I posted my same “Fucking idiots” comment on the YouTube page, the guys deleted it. Guess they don’t like people pointing out that “It’s all fun and games until someone loses an eye.”

I think it’s extremely irresponsible of Make Magazine to post this, encouraging risking other people’s welfare like this. Fortunately, it also isn’t up to Make’s usual high standards of quality, so there’s no friggin’ way people could replicate it just from watching the video. The guys explain the software (sort of…barely), but nothing of the hardware. Lasers? Projectors? How? What’s the controller? Never mind, don’t answer that.

I love Make Magazine, and I love hacker ethic, but hate irresponsible hacker ethic. There’s a lot of that going on here, and I’m amazed Make Mag is encouraging it (especially with such a crappy demo.)

Michael W. Dean
http://www.stinkfight.com

You don’t get it. The persistent image is from a standard projector, not a laser. The laser is simply used as a fancy mouse for input to the drawing program.

“I posted my same “Fucking idiots” comment on the YouTube page, the guys deleted it. Guess they don’t like people pointing out that “It’s all fun and games until someone loses an eye.”

Or maybe he just doesn’t wish to abide your vulgarity.

That’s a chance I’m willing to take from some guys who snicker like grade schoolers at the thought of projecting “nasty stuff, like body parts” (i.e. genitalia) on a public building viewable by anyone of any age.

MWD

I’m square, real melvin, fuddy duddy, a buzzkill. I don’t think people should point lasers at places where people may inadvertently look directly into them.

Maybe you could tell how how lasers work, if you are so smart.

I can tell YOU how they work, and there is attenuation over distance and there is dispersal through windows with most lasers.

We are not talking about small laser pointer:
http://en.wikipedia.org/wiki/Laser_pointer
“in USA this output is limited to 5 mW…”,

30 mW (“++”, which I take to mean “or a good bit more, if you can get your hands on it) is a much more powerful scientific or industrial laser.

According to Wikipedia, “Today, it is accepted that even low-power lasers with only a few milliwatts of output power can be hazardous to human eyesight.”

also:
“Even the first laser was recognized as being potentially dangerous. Theodore Maiman characterized the first laser as having a power of one “Gillette”; as it could burn through one Gillette razor blade.

At wavelengths which the cornea and the lens can focus well, the coherence and low divergence of laser light means that it can be focused by the eye into an extremely small spot on the retina, resulting in localized burning and permanent damage in seconds or even less time.”

…Certain infrared lasers with wavelengths beyond about 1.4 micrometres are often referred to as being “eye-safe”. …..The label “eye-safe” can be misleading, however, as it only applies to relatively low power continuous wave beams and any high power or q-switched laser at these wavelengths can burn the cornea, causing severe eye damage….”

—-
MWD

Read post #18.

And then, JUST MAYBE, you will be quiet.

Somehow I doubt it, though…

also

#17 posted by Moon
“Maybe you could tell how how lasers work, if you are so smart.

“I can tell YOU how they work, and there is attenuation over distance and there is dispersal through windows with most lasers.”
—–

Moon, you may be right in both counts. But would you be willing to test your extensive knowledge by:

A. Having a 30mW ++ laser pointed into your eyes from a distance through a window?

and

B. Take on the responsibility (ethical and legal) for trying this on unknown numbers of unwitting non-consenting humans?

Also, Moon, I find in interesting that in one post, you are saying “I’m not absolutely sure, but I think….” then in the other post implying some sort of expertise which trumps that of the other people posting here. That seems kinda specious, and also kinda grade school to me.

I’m no expert on lasers, but have enough layman knowledge of science (and law) to know that pointing them into office buildings with windows is a damn bad idea.

–Michael W. Dean
http://www.oreillynet.com/pub/au/3220

but: They’re spreading out that 60mW beam over ~100 square meters on the front of the building, which is ~1 million square centimeters.

so: The power that someone in the building looking out the window is going to be exposed to is about 60 nanowatts per square centimeter.

and: The maximum safe exposure to a visible laser (in round terms) is 1 milliwatt per square centimeter.

so: There is a safety margin of about 10,000 in what they’re doing.

….

I thought MAKE is meant to encourage people to go out and try things themselves, and to be informative. The Graffiti video explains precisely nothing about how to make one of these things, and it doesn’t even go into how to check if what they’re proposing to do is safe or not, hence the discussion we’re having above.

MAKE’s normally interesting, but this edition was too dumbed down — perhaps it’s the new year and so they’re running repeats??