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As a controls engineer who deals with CDRH regulations for laser sensors, laser engravers, and and laser cutters on a regular basis, the crap that some light sh

As a controls engineer who deals with CDRH regulations for laser sensors, laser engravers, and and laser cutters on a regular basis, the crap that some light shows get away with is criminal. The lasers used in light shows are only allowed because they're moving; if you looked directly down the beam while it held still your blink reflex would not save your vision. Fortunately, you've got natural liquid cooling: your cornea is bathed in tears and your retina is surrounded by fluid-filled tissues, so there's a safety window of a few milliseconds while the laser pans across your eyeball too fast to cause dangerous temperature rise. If the laser beam slows down - if the encoders/resolvers on the galvanometers register insufficient change in the mirror angles - the controller will shut off the laser. I don't have sufficient trust in my own professional, methodical, high-quality work using top dollar equipment to open up a machine without safety eyewear and lock out/tag out procedures; I have even less trust in products for the lower-margin, faster-paced entertainment industry. On top of that, it would not surprise me if a camera sensor has slightly less heatsinking compared to human eyeballs...but the fact that the safety margin is so thin that cameras can be damaged makes me not want to go to a light show!

deepsun 5y ago
Last time I was at a concert in San Francisco Bill Graham auditorium, I noticed that lasers travelled fixed path always pointing at the walls or between balcony levels, never at people.
- spurtrenolds 5y ago
  Of course they are not aimed at people! See the comment below regarding concerns of misalignment, limit stops & containment for beams with the power to cause permanent blindness. I'm sure some venues handle this safely [1], but powerful lasers are being treated far to casually for my liking. [1] Though I wonder what would happen if you asked for a copy of their risk assessment?
GoodbyeMrChips 5y ago
> the crap that some light shows get away with is criminal Seconded. Telecoms laser engineer here, and amateur musician. I'm astounded how casually class 3B and class 4 lasers are treated in the entertainment industry, or that using them in free space with poor travel limit stops / beam containment is even legal..... Often it appears little-to-no consideration is given as to what happens if a beam becomes misaligned or reflected into the audience. You only have one set of eyes.
- LeifCarrotson 5y ago
  I felt hoodwinked when it turned out when I'd designed in a class 1 (intrinsically safe, power limited) time-of-flight laser distance sensor and the purchasing department replaced it due to lack of availability for a 'superior' range class 2 (DO NOT STARE INTO BEAM for more than 0.25 seconds, intentionally suppressing your blink reflex can cause damage) sensor. Flags went up, every stakeholder was pulled in, we redid the risk assessment (aware of the temptation to fudge it to ship the equipment on time) and eventually allowed it after replacing a clear anodized part with a black anodized one and festooning the machine with "Do not stare into laser" stickers. My roommate in college was a stagehand, we talked a bit about the safety and it appears the consideration is more on the scale of "We try not to shine the lasers in people's eyes" and less like "We have redundant, proven processes that ensure people cannot be harmed." It feels like they've missed an important distinction between what's acceptable for your own purposes and what's acceptable risk to impose on someone else. Safety when messing about in your own backyard would often not pass OSHA requirements, that makes sense because it's your own risk and your own reward, this is ethically different an industrial scenario where you're forcing someone who's just trying to feed their family to endanger their eyes for someone else's profitability, similarly, concertgoers should and do assume that entertainment light shows are safe, while [some in] the entertainment industry take it much more casually.
jnwatson 5y ago
The number 1 lesson I learned in laser safety class: do not look into laser with remaining eye.

deepsun 5y ago

Last time I was at a concert in San Francisco Bill Graham auditorium, I noticed that lasers travelled fixed path always pointing at the walls or between balcony levels, never at people.

spurtrenolds 5y ago
Of course they are not aimed at people! See the comment below regarding concerns of misalignment, limit stops & containment for beams with the power to cause permanent blindness. I'm sure some venues handle this safely [1], but powerful lasers are being treated far to casually for my liking. [1] Though I wonder what would happen if you asked for a copy of their risk assessment?

GoodbyeMrChips 5y ago

> the crap that some light shows get away with is criminal Seconded. Telecoms laser engineer here, and amateur musician. I'm astounded how casually class 3B and class 4 lasers are treated in the entertainment industry, or that using them in free space with poor travel limit stops / beam containment is even legal..... Often it appears little-to-no consideration is given as to what happens if a beam becomes misaligned or reflected into the audience. You only have one set of eyes.

LeifCarrotson 5y ago
I felt hoodwinked when it turned out when I'd designed in a class 1 (intrinsically safe, power limited) time-of-flight laser distance sensor and the purchasing department replaced it due to lack of availability for a 'superior' range class 2 (DO NOT STARE INTO BEAM for more than 0.25 seconds, intentionally suppressing your blink reflex can cause damage) sensor. Flags went up, every stakeholder was pulled in, we redid the risk assessment (aware of the temptation to fudge it to ship the equipment on time) and eventually allowed it after replacing a clear anodized part with a black anodized one and festooning the machine with "Do not stare into laser" stickers. My roommate in college was a stagehand, we talked a bit about the safety and it appears the consideration is more on the scale of "We try not to shine the lasers in people's eyes" and less like "We have redundant, proven processes that ensure people cannot be harmed." It feels like they've missed an important distinction between what's acceptable for your own purposes and what's acceptable risk to impose on someone else. Safety when messing about in your own backyard would often not pass OSHA requirements, that makes sense because it's your own risk and your own reward, this is ethically different an industrial scenario where you're forcing someone who's just trying to feed their family to endanger their eyes for someone else's profitability, similarly, concertgoers should and do assume that entertainment light shows are safe, while [some in] the entertainment industry take it much more casually.

jnwatson 5y ago

The number 1 lesson I learned in laser safety class: do not look into laser with remaining eye.