crowd scanning in the USA

[hibbity]

OK, first off, im new, hi everyone

now that that's out of the way, down to discussion

i get the idea that crowd scanning is prohibited/illegal? in the US.
why?

also, how illegal are we talking, fine /misdemeanor/ assault with a potentially harmful weapon/device, one count per person in the audience?? jail? whats the deal?

also, if i have a few friends over at my place, and we do some crowd scanning? is that morally wrong, or illegal? its a private show in my garage or basement, maybe my back yard on a nice night.

where/what are some guidelines that aren't too technical, for crowd scanning?

what are the maximum outputs recommended for each color?

i mean, hurr durr, watch me point a 2 watt beam at your black shirt and hold it there, i get that he'd probably die in a fire.

i kinda wanna scan, but i dont want to hurt my friends.

advise me please.

[hibbity]

Oh yeah, i live kinda close to an airport. If i take my projector outside, will the cops come?

[White-Light]

what are the maximum outputs recommended for each color?

If only it were that easy!!

There is no easy way of calculating MPE at the moment. (There is a simple method) but you still need a power meter, an oscilloscope, a good controller such as Pangolin software and some technical knowledge as you need to start measuring scanner velocities!!

There are some software developments that may simplify this in the future - however I can't discuss them as what was said to me was said in confidence.

However, for now there is no "easy" method. Just doing it risks eye damage, possibly permanent, for you and your guests.

As for the legalities in the US I wouldn't know.

You will also find it difficult to do a show in your back yard for anything other than graphics as the fog will just disperse too quickly. Only solution for an outside show is a marquee (or a totally still day and a serious investment in fog machines numbers and fluid!!!!)

[mixedgas]

Yes, pilots are required to report ANY laser activity by FAA directive, and they do. Even at a outdoor show I did with FAA approval and a Notam, they reported it frequently, 500 mW 4 miles from the airport, termimated on the wall, was visible to pilots on approach and climbout. Nice clear air in Phoenix. ATC was kind enough to tell us the number of radio calls they got that evening, and it was a large number.

Steve

[mixedgas]

Its still assault and battery or criminal endangerment if you mess up. The civil lawsuit would be far worse. Because you asked about it here, the lawyers have you cold in their sights if you ever do it.

The federal charge for 21 CFR is fines of 300,000$ or Six months in jail,

The Interfering with a Aircraft one is upto 14 years and a huge fine.

Your local cops or sheriff beating you up for doing it, priceless.

If you do get charged or sued, the cost of the expert witness to defend you would be 10,000 to 20,000$.

Here is the gotcha,

First off: Damage:

If you use too much power, and damage someones peripheral vision, your friend gets hit by a truck crossing the road, because it works mainly in the subconscious and you dont think about it, you just use it, and its the part of your vision that protects you from collisions and helps with driving etc.

If you get the main portion of the retina, it does not heal, and your friends end up with permanent black spots in their vision. In a few cases, the brain will try to work around the damaged area,and the black spots dissapear but then a few months down the road your friends have trouble seeing or reading or get migrain headaches.

Worse case, you hit the fovea on the macula, where the optic nerve joins the retina INSTANT BLINDNESS.

Now while done by professionals with exposure measuring systems , it can be safe, but if you do not own a power meter, a oscilloscope, and do the math. NO. You cannot assume a modern low cost solid state laser stays at a known amount of power, without light feedback circuits etc.


While in Europe under strict conditions its done all the time, The point is, its done under strict conditions.

NO amount of software helps you if you do not measure the power and divergence.

The point of the matter, is, DONT DO IT unless you spend a considerable amount of time and effort having your laser checked out and you do the math.

BTW< the effects are cumulative , the allowable exposure adds up over time, and there is a limit on total exposure. Effects are only safe for limited amounts of time, ie, a effect can be designed for 15 seconds of use once during a show, but of you used that effect 5 times in the show instead of the 3 times it was calculated for, , it could blow the MPE (maximum permissable exposure) limits.

This is a very tricky business.

If you keep the total power to about 4 mW and the beams have no hot spots, or areas where they totally stop, your marginal, buit it can be done, However that means you have just invested in a nice fogger,invested in a 300-400$ power meter, and are fogging the room to a point your friends may not want to hang out in it.

BTW< in Germany etc, the rules are , someone ELSE checks your show to make it safe, and that person has taken a course on how to do it.

YOU ALSO HAVE TO CHECK EVERY SINGLE ANIMATION OR STILL FRAME IN THE SHOW!

If your laser is pulsed, ie qswitched or a copper vapor etc DONT EVEN THINK OF DOING IT!!

JUST DONT DO IT.


See, in Europe, if you go to a club to party, the assumption under the law is you assume you know your taking a risk by going to a bar or club. Here in the states, the rule is different, the club or bar is legally bound to make sure your safe. Free Will doesn't matter under US law.

BTW< You have to tell your friends that this could be unsafe when you do it.

And one of the side effects of doing this is you go around straining your eyes looking for damage, or every time your out driving, you wonder if that floater in your vision is the result of a clump of cells blown off your retina the night before.

BTW< your eye is a lousy power meter, you can't just go by "This looks safe".

And if you do this in a confined space, you have secondary reaction problems, ie you just flashblinded a friend, and they trip over a coffee table and hurt their back.... You get the idea.
In a big club a person can turn away if its too bright, in a apartment or basement, that is not the case.

Also in the states, you hit extended liability, "Well I have vision problems now, and two years ago my friend scanned me" , well, guess who just got sued.


Steve

[LASERGUY]

For my full time job I am an optical engineer.... I design barcode scanners
We do these types of calculation all the time for UL, CDRH and IEC all the time..

I do have access to allot of equipment to measure things such as this...

But even still I do not want to bother. My personal rule of thumb is that there is no need for unnecessary exposure to laser light.

I do understand how cool an effect must be when you have a beam fan sweep down in the audience but the risk involved in my mind are just not worth that effect.

I am curious is anyone within the forum has the same butterflies when performing a show that I do?
I feel an overwhelming reasonability to my audience to ensure their safety.

When I was starting out with shows at my buddy’s house party in the basement I took comfort that the aerial effects are way over their heads... I masked my scan head so none of the clear aperture would yield beams into the crowd.
The aerial effects in my mind are still powerfully cool... I felt that the shows were definitely still cool even if the beams were not hitting the crowd. In fact, for your audience to really see and appreciate the effects you need to pull them away so they se the full stretch of the beams.

I assume people love crowd scanning in the clubs and such because the drunk and high audience members want to be submerged in light.... I’ve have been on that dance floor plenty of shots in me and I love when that music is pumping and lights going. But that’s what you use the intelligent lights for... Keep the lasers out of reach...

Anyway... I am rambling.

I am by no means disagreeing with the effects.... I think some may think I am crazy fro not seeing the enjoyment in crowd scanning. But I like Steve’s comment about driving the next day wondering if that floater is from the night before.
Just remove these questions all together.
Plus..... People are crazy and mean.. They will do anything to point their finger at another person.
Any question that by getting hit by one of your laser beams may have caused something to happen.. Oh man will they chase that.

One last point.... I know many are working without a variance.. This isn't so great.
But at least at the end of the day... if shit hit he fan... you can at least stand by that you were practicing safe use with lasers.
The argument may not help but at least you are following the basic rules of laser safety.

When I do my shows for the children (5th graders) I always pull out two lasers.
I show them my older HeNe lab lasers.... It’s a big beast... I point out the large cord and safety light…. it cost $3000 at one time.
I ask them "Looks kind of intimidating... would you just play around with this when in the Laser lab?" The little kids shake their heads and say "NO!?"

Then I pull out my $5 keychain laser you get at Spencer gifts... All the kids get excited and tell all these stories about what they or their older brother or sister did with their laser keychain.

I then go on to point out that that the big "scary" laser puts out 1mW.... Their laser pointer key chains put out 5mW (5x's the power)... Their little mouths drop to the floor Guess these little laser pointers aren't much of toys are they?

I think we need to start reminding ourselves of this on the forum..... These little cheap Chinese eBay lasers are putting more power out then the old scary large frame lasers did. What needed water-cooling, 3-phase, weight a million pounds.... is not in the palm of our hands.. We need to respect the power of the laser more than ever.

JUST DON'T DO CROWND SCANNING if you don't know exactly what you are doing and have been trained by those who know.

Just my lame boring self

[LASERGUY]

I seriously need to use spell check

[mixedgas]

I think you just wrote the sticky.
Aud scanning, done right, can be a beautiful thing, but doing it right requires a huge amount of funding , long amounts of programming time (days) and the main audience for it is raves, the Cleveland Orchestra is not gonna hire me for aud scanning. Also in a club, in many cases, the intelligent fixtures are gonna wash out legit aud scanning a lot of the time. Some of the 500 or 1000 watt metal halides are brutal. Not to mention 3 pieces of Phlatlight LEDs at 35 watts each in a fixture.

Steve

[mixedgas]

I seriously need to use spell check

Me Two,

I find the edit button to bee highly useful with our atrociously hard to spell language. And I avoided the fowl language I wanted to use to describe English.

Thats while you'll sea I audit about 20 times per post.
Steve or is it Stephen ?

[Corporall Clegg]

My uncle seems to think this laser http://www.americandj.com/ProductDet...sers&txtSearch= is safe for crowd scans I have told him he is incorrect but he will not listen can anyone here give me a professional opnion he won't take my word for it maby he will take somone elses

Thanks
Aloha