Reke 500 and Crowd Scanning

I know this is not exactly safe, but what would be an acceptable distance to crowd scan with the Reke 500?

one mile is safe.. J/K
crowdscanning USED to be quite common- still is legal in some countries- In Moscow 20 some people were scanned at a show and got eye damage-IMHO dont ever scan people -- its just a bad idea.. why would you want to lase people anyway??

there is so many other ways to do lasershows w/o the need to shine them into peoples eyes- lawsuits are a good reason to avoid- ALSO w/o a lot of somewhat expensive mods to a REKE it would be an illegal projector to display in ANY public place even w/o crowd scanning.. A single phone call to the FDA could get you a visit from the laser police-thats no joke!!! They may not take you to jail but will issue some kind of ticket and prolly(rightfully) take your lasers with them.

hakzaw1 said:

one mile is safe..

Click to expand...

I'm gonna second this, and not as a joke.

Read up on NOHD.

Here's all the information you need: http://safety.uchicago.edu/files/Laser MPE and NHZ Calculations.pdf

It depends on the divergence, wavelength, beam size, exposure time, distance from laser to audience and exposure time.
Take those numbers to find out hazard factor, if it's safe then feel free to audience scan, but you may want to move the projector a couple meters away from what is safe, just to be cautious incase your calculations are off.

Light show with lasers . - YouTube

Found this video. I'm thinking this is totally unacceptable?

keoky said:

Light show with lasers . - YouTube

Found this video. I'm thinking this is totally unacceptable?

Click to expand...

People can walk right up to the PJ and put their face in it :O

That's a very bad idea.

That looks very unsafe...

Unsuspecting people sitting in the foreground facing the laser without being near or part of the "dance floor" being repeatedly blasted in the face and eyes.
It seems like a typical wedding reception type of occasion so the audience can have their reflexes slowed and dulled by alcohol thereby causing even more damage and problems from direct exposure.
Stupid with a capital "S" !

Now if anyone from that event develops any sort of vision issues and finds out that they were exposed and could rightly sue this guy for everything he is worth AND possibly take a portion of everything else he makes in the future...

Do you think it is worth it ?

"Typical disco setup" Yeah, people tend to be dancing at typical discos too

Yes, looks crazy unsafe. Ok what if it was on the OTHER side of the room, 10 ft above the crowd but pointing down. Would the length of the room attenuate the beams enough for it to be safe?

Here's another video. https://www.youtube.com/watch?v=94vHZOaiZrI

Obviously these guys are experts and everything had to be measured correctly, but these lasers seem 5x brighter and stronger than the reke 500 yet they're still crowd scanning around and after the 2:00 mark. I'm just trying to wrap my head around this confusing subject.

Thanks

Crowd Scanning /Audience Scanning requires the purchase of a oscilloscope, fast photodiode, and a means of accurately measuring the beam diameter and divergence. Until you have all those, and some practice, you should not do crowd scanning.

Time duration of the effects matters as well.

The math has to be calculated and tested for each effect, not just for the whole projector.

Or you need to purchase a "PASS" system from Pangolin, which will not fit in a REKE.

There is a requirement for you to do "Quality Control" on your effects each night.

There are a few possible shortcuts if your in Europe, but not if you live in the US.

Steve

Just because what you see looks like it is brighter or more powerful doesn't necessarily mean that the portion of the beams scanning the crowd ARE such. Besides software modifications and physical glass filters that can be used to reduce the power for portions of the projections you have to also consider that the operators may have taken the time to make sure that the crowd scanning portion isn't noticably different to the observer. So anyone looking in from the outside, so to speak, would think that those bright blasting beams are going through the crowds while they might actually diminish in entensity as the get lower so it would be completely indistinguishable.
Now there is no way to be sure exactly what was being done in that situation but the question of whether or not you want to risk everything (today and in the future) on doing it remains up to you.

Phonecamera videos are just what lawyers love-- evidence for free.
and at youtube they document where, when and name the DJ doing the scanning-- All they need to own you is a doctor who will gladly show the jury photos of eye damage--case closed... I cant see the atraction at all-- is having lasers aimed at people supposed to look cool to others or to those being lased.???
I have been to many lasershows and 5 LEMS- We can do pretty much what we please at LEMs and even with all signing waivers of liability the audience does not get scanned- at SELEM we are allowed to enter the balcony where we can definetly get scanned but the only ones who dare to go there do that for vids and pics and all take great care to avoid eye shots..I shield my eyes(with the bill of my cap) and wear my glasses and try to only view the view thru my cameras. We are all told in no uncertain terms that the balcony is NOT a safe zone.

Greetings , Thats my setup your merrily tearing into there . I'm based in the Uk where laser use isn't covered by a whole lot of regulations . Lasers are an element in most of my shows and where possible we follow the guidelines of 3m up in the air . In this particular venue that wasnt possible due to the location of where I was setup in an alcove . The lasers are only on when the dj is behind the equipment and if we are away from the gear then they are locked off and the keys removed. In venues with high ceilings it isnt a problem as the laser is aimed upwards . If customers get too close to the lasers again they are turned off . I have no wish to injure people I want them to have a good night .

I have been using disco lasers for many years and have not heard of anybody being injured by one . Other than the cases in russia it doesnt seem to be that big a problem .

As the output of these lasers increases I believe it will become a problem as dj's are now getting their hands on lasers with 5 watt outputs . There should be some form of control over class 4 equipment as these are the ones I believe are going to cause the issues .

I realise the reke is pushing the limits of what is deemed safe which is why next on the shopping list is a dac to give me greater control over it and be able to reduce the output power where needed .

Somebody mentioned filter lenses , Where can you get these from and how do they affect the laser output ?.

Any help or advice you can give me would be great as I like my rigouts to be as safe as possible as has been rightly said people sue these days at the drop of a hat which is why I have PLI .

I'm not going to deny I've crowd scanned before, how you do it really needs special attention to detail. Like the UK, here in Aus (At least outside of WA) there really is no guidelines or regulations at _ALL_ for lasershows (Although generally you should check with CASA for outdoor stuff).

However, I'd be fairly careful with the cheap Chinese lasers like the REKE. Having built my projector from the ground up over many years, I know _exactly_ how everything works, and exactly where the problem is if something fails. If you are using the cheap Chinese lasers at least semi-professionally, I believe it really helps to know them inside out, so if you ever have any issues, you know how to deal with it.

Also seeing as the REKE lasers have only 10K scanners, I'd be cautious using fast moving beams as a "safety feature", as 10K is fairly slow in terms of a high power beam. Could be worse, but it's not great either.

Always monitoring what people are doing is a good thing, however over time I found it's really not worth the hassle and risk. OTOH my projector does about 1.4W OTF, a bit more than the ~500mW or so of the REKE, however in terms of eye damage, 500mW is still very dangerous.

The problem with saying "It hasn't happened yet, so it should be fine" is that when it does happen, shit goes downhill _fast_, so in reality, you really, really don't want it to happen at all.

Being a DJ, you'd also be well aware of issues with strobes and fog machines too, it's one of those things that are rare, but if/when they do happen, it can be a serious problem for your business and reputation. PLI is great, but it's not going to save your reputation if you accidentally blind someone.

None of my shows uses dedicated strobes and any strobe effect on other lighting is kept to a slow speed . I use a hazer rather than a traditional fogger although the venues that let you use either are getting fewer .

I'm surprised you say its a 10k scanner as its sold as a 20k unit . Might have to check the galvos just to be sure .