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Thread: Info on scan fail systems

  1. #21
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    Quote Originally Posted by greenalien View Post
    The safety board made by HB Laser is a little difficult to find on their website, so here's a link http://hb-laser.com/hb-en-apolloscanner.html
    When is technology going to catch up in this area? Who wants to have to twiddle pots to set the 'safe' zones ? This must be a right royal pain in the you know what if you have to set them every time.

    Jem
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

  2. #22
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    Yes, an interesting thread. Between us all we could probably fill a forum with this topic, but I will try and keep things as short as possible.

    Before I do so, did anyone see the Kahn fight on Saturday? I didn’t see the fight myself, but caught a few seconds of him emerging from a laser tunnel that went straight in to the faces and down the lenses of the cameras surrounding him…

    Kevin, good to see your post. You are quite right, the ocular hazards are just one of the hazards that need to be considered in the risk assessment of any laser installation. The typical laserist is likely to come across a whole range of hazards with potentially more severe consequences such as electrocution, manual handling, working at height, vehicle movements, slips trips and falls, and now, the new noise at work regs, to name but a few. And of course death or damage to property are both severe consequences of some of the hazards we have to work with. With risk being a function of the likelihood of an occurrence and its consequences, these extremes are thankfully rare occurrences in the entertainment industry. (although in the UK there have been recent deaths from rigging incidents, so it does happen). Solid-state laser projectors have done a great job in removing many of the traditional risks in using lasers.

    Few would argue that losing one’s eyesight, or having it damaged in someway is not a serious injury, which is why the regulations and guidance on the matter exist. (such an injury is actually legally reportable under RIDDOR 1995, so it is not trivial) Therefore the ocular hazards are always a hot topic for laserist to discuss. On our one day course we try to concentrate as much as possible on these hazards, as there is so much to squeeze into one day. More generic workplace safety H&S courses exist, and we would recommend that people running a business would use those to become familiar with more general safety matters and requirements. For example, it would be quite easy for me to spend a day going into the theory of H&S risk assessments, and another day on HSG65 (yes 65, not 95 the laser document) etc. And we do touch on key related elements of HASAWA1974, MHSWR1999, and PUWER1998 etc, but what the attendees generally want to learn about are the ocular hazards, and for many it is the first time that they get to look at the nitty gritty of understanding HSG95, bioeffects, or the MPE table and formulas. Some people grasp it, even if it means a couple of follow up emails, and others see it and switch off. But in the least, even if you understand the process or not, people learn why MPE is important, and will hopefully think twice before pointing a laser at someone’s face.

    Kevin you are right in that attending a one day course on the subject does not make anyone an expert on the subject. But it does, I think, serve to give them a good solid grounding to work from. But people are different, and come for different reasons. For most part, there is a genuine reason to attend and want to learn more about the subject. Sometimes I’ll see these people several months later, and get heartened with the fact that they are putting some of what was said into practice. And I generally have quite an open policy on people coming back and asking for extra advice. But for others, all they want is the certificate of attendance. Fair enough, it’s up to each individual as to how they want to run their business. End of the day though, someone who has attended the course should be more knowledgeable than someone who has just cottoned onto the fact its possible buy low cost laser products from China, and box shift them, or install them in venues as if they were any other lighting effect. And believe me this happens too! And they can get away with it if the local authority are not to hot on laser installation safety. – There is the belief that if a Local Authority has allowed an installation to go ahead, then everyone is in the clear. No. Under UK H&S law, the duty of care is always with (primarily) the venue owner and the contractor/suppliers it employs.

    HSE are aware of the concerns about the low cost Chinese products being used by DJs. I spent a good five hours with them last week showing, with measurements and calculations, how much the MPEs are being exceeded by. There is a work happening at the moment to help tackle the problem. But my feeling is that it is too widespread and impractical to police. Sadly we will probably have to end up waiting for an injury to be reported, then watch the following lockdown that will occur. Bottom line is that HSE are making a bit of an effort, but in their portfolio, with limited resources, there are bigger fish to fry at the moment. (IMHO they are probably covering their arses by showing a bit of an interest now)

    Injuries from lightshows do exist, but to a very large extent are unreported. I know of an injury I have, and now have seen a photo of my retina showing a scar. I know also of many peers that have suffered injuries, but don’t make them known publicly. (perhaps it’s not good for business? ) Rockwell’s limited database has a few reports of injuries from visible lasers. Some at shows. What I find interesting is that when someone knows about a hazard, then they are more likely to notice an effect of it. Rockwell has reports of workers who have been hit with 20-30mW lasers and have an injury. Measurements I have taken show that people in village hall scenario are likely to be exposed to much higher irradiances. Yet Aunty Marge, doesn’t think for a moment that Dazzling Darren’s Disco Show has lighting that could burn her retina.

    It is public perception though. People don’t think a laser show should be unsafe. “for surely, everything has to be safe, and it wouldn’t be allowed.”. Yet a few years ago, when it was publicised in the media that laser pointers were dangerous, injuries appeared from 5mW laser pointers when we had the spate of claims from bus drivers and the like.

    The visual cortex is very complex and can deal with hiding many deficiencies in eyesight, including blindspots. The same can’t be said of CCDs and DLPs that people have started to notice get damaged by a laser strike.

    Back to the issues in the post, Bill is right. Laser beam propagation is not something that can be accurately predicted, especially with the types of laser we use in the entertainment business. Which is why when making the laser safety case, actual measurements are an extremely important part of the process. I’ve been asked, and have thought about running an advanced laser safety workshop for those that are interested in getting into more practical assessment of laser effects that hit the faces of the audience. Our new software can help in this process by telling you what you should be looking for in the first place. When you go to check a measurement, and something is out, then it’s time to take a look at where the discrepancy could be coming from.

    Carl, the NOHD for a static beam from a 2mr 150mW laser is as Kevin wrote, 43metres, and for 200mW, 50metres.

    If you had the 200mW laser producing a scanned effect that contained 1ms finger beams striking the pupil several times a second, the hazard distance would still be 37metres. A faster scanned effect such as a tunnel, giving a typical 100us exposure and the distance is reduced to below 30 metres.

    Jem and Carl, to answer your question about what the pros use, it is difficult, for don’t see many of them using a lot. Does anyone here really think that the laser effect on the Kahn fight was checked and measured before putting into people’s faces and cameras?, or that the actors on Skins were warned about laser radiation during the filming of episode 1 in season 2? Or that the lasers we see in audience scanning in many of the UKs clubs are below the MPE? People do it because they can get away with it. And they will as long as no one appears to get injured. Now we have the mobile DJs doing it and in much greater numbers and higher energy levels than anytime in the past. … there are those that have told me, “give them enough rope… and…”

    Part of my work involves me working with venues, organisations, and production companies in relation to laser safety, and as a such, a lot of the work I carry out for these people is under NDAs and client confidentiality. But there are many situations where there are simply no workable solutions to get the effects to scan below the MPE. For example, putting an undiverged 5W (or even the smallest class 4 laser) in a small nightclub is never going to work in terms of getting below the MPE, and with so many projects like this I have to walk away, if they won’t listen to the advice. But there have been several projects where we have been able to put a good safety case together in parts of the country where the authorities are more observant on laser show safety matters, and the operators want to achieve a good effect. So it is sometimes possible. What they are looking for are competent operators, a sound and thought out methodology covering the foreseeable failure modes, and evidence that the emissions have been checked and can be contained. This inevitably costs time and money in terms of the work involved and calibrated instrumentation required to take the measurements. But some clients recognise the need for safety and understand such things are necessary parts of the project costs.

    Best regards

    James Stewart


  3. #23
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    Hi

    Mr. Green Alien

    I may be completely wrong and if I am I apologize, but my understanding is that if your prototype is to be used anywhere in public either paid or unpaid, you have a duty to ensure that your public or any other person is not exposed to any unnecessary risk. If you are only using your prototype in your own garage on your own with no one else in your garage then it is up to you to assess the risk to yourself only.

    I am fairly sure that it is a legal requirement for equipment to be CE marked after the 1st Jan 1996. So if this is inaccurate could you please post some information to counter claim this as this is quite important.

    You can self certify your own equipment and there are may documents to help you, but you do need to construct the unit referencing all of the relevant standards regarding low voltage directives, BS standards EU standards etc.

    James thank you for your very detailed post.

    Jem, yes I do audience scanning and can put together a very interesting argument, backed up by some very careful measurements and statistics and very controlled multi redundant control systems. We only do this at private parties where people are made aware of the hazards prior. We use diverged laser power using a 100 mw single wavelength projector with over all scan fail.
    A risk assessment has been put together, but not submitted as yet as we hope to obtain approval on this method independently from possibly John Tyrer at Loughborough. There is still lots of research we need to do (time permitting) before we make the method public. It may not be too far away from Pangolins PASS system, but we don't want to step on his patient (Don't send the lawyers across the pond yet Bill).

    Regards

    Kevin
    Free Guide Dog Puppy With Every Laser Show Lynx Laser UK

  4. #24
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    Quote Originally Posted by Lynx View Post
    Jem, yes I do audience scanning and can put together a very interesting argument, backed up by some very careful measurements and statistics and very controlled multi redundant control systems. We only do this at private parties where people are made aware of the hazards prior. We use diverged laser power using a 100 mw single wavelength projector with over all scan fail.
    A risk assessment has been put together, but not submitted as yet as we hope to obtain approval on this method independently from possibly John Tyrer at Loughborough. There is still lots of research we need to do (time permitting) before we make the method public. It may not be too far away from Pangolins PASS system, but we don't want to step on his patient (Don't send the lawyers across the pond yet Bill).

    Regards

    Kevin
    Kevin, I was having a go regarding your risk assessment regarding audience scanning with my tongue firmly in my cheek perhaps it didn't come across too well in the post, If you recall we've had discussions about safety, and as you know i'm firmly on your side and the side of all safety conscious laserists.

    As for myself, i'm not quite ready to audience scan just yet

    Cheers

    Jem
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

  5. #25
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    Quote Originally Posted by Lynx View Post
    but we don't want to step on his patient...
    Err... Should that be 'patent' ???, I was just wondering who was ill in Bill's office, sounds too much like the UK NHS to me

    Jem
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

  6. #26
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    You do knoww thas ams dykylexzik dont y.

    regdsa

    Kevin

    Still learing how to spil
    Free Guide Dog Puppy With Every Laser Show Lynx Laser UK

  7. #27
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    Quote Originally Posted by Lynx View Post
    You do knoww thas ams dykylexzik dont y.

    regdsa

    Kevin

    Still learing how to spil
    Tryping errots are easy to make

    Jem
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

  8. #28
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    Quote Originally Posted by Jem View Post
    How about some more information as to what's actually available as regards safety systems? Why is it so difficult to find out what's out there, is it some sort of big secret?
    Hi Jem,

    Well, if you are looking closely, you will see that at Pangolin, there is no big secret . We try to be as open as possible. I wrote an entire article on this (actually many), but a single, condensed version is on our web site here:
    http://www.pangolin.com/resguide09a.htm
    And we also have a lot of information available on our web site in the form of John O'Hagan's article here:
    http://www.pangolin.com/resguide09b.htm

    Really if you put in the time, those two articles will pretty much get you all of the information you need to know. All of the information is there, and, for the most part, the technique that Greg and I use is inferred in the first article I point to above.


    Quote Originally Posted by Jem View Post
    Bill, What exactly IS your system for diverging the beams and how much does it cost?
    Jem, it's not "my" system. It's just a simple lens. All you need to do is increase the divergence *somehow*. One *somehow* way of doing it is to adjust the collimator lens on cheap lasers themselves. Another *somehow* is to put a two-lens collimator just before the scanners, and adjust it so that it gives you a divergent beam. Yet another *somehow* is to put a long focal length PREFERABLY NEGATIVE!! lens directly after the scanners. Any of these techniques will work. It really doesn't matter how you do it, as long as you make the beam divergent.

    Heck, at a PL meeting in Florida, we borrowed somebody's eyeglasses and taped them in front of the projector...

    By the way, Buffo came to our office and saw a Discoscan lens. You can read about it here:
    http://www.pangolin.com/wideangle/index.htm

    The Discoscan lens increases the scan angle such that you can reach a 180-degree by 360-degree scan field. It also increases the divergence too, although that is just a side effect. Buffo is a bit confused though, in assuming that we always use that particular lens any time we do audience scanning. That is not the case.


    Quote Originally Posted by Jem View Post
    Perhaps someone could add some info on exactly what is required to enable us hobbyists to make our projectors fully 'safe' for audience scanning. Even if we can't afford it at least we'll be fully informed and it will give us something to aspire to.
    We actually did a bit of this at a previous PL meeting in Florida. The SINGLE BIGGEST thing you need to do is increase the divergence. You will find that somewhere between 5 and 10 milliradians is the magic number. This is far more important than any other thing. If you have a beam with proper irradiance and no scan fail system and no special software, that's better than having software but no lens and no scan fail, or having a scan fail but no software and no lens.

    You have to increase the divergence period (unless you want to use 5 milliwat lasers). This might seem controversial to some, but not to the people who really know what the hell they are doing. James, back me up here...

    Anyway, that's step 1. Step 2 would be go do an assesment somehow some way. James' software is probably one way to do it. Another way is with real measurement equipment, but we won't expect hobbyists to have it. HOWEVER, honestly (and I am talking honestly here), it is conceivable that an assesment could be done for your particular power level and room size, and give you a divergence number that will work for most shows. So it is conceivable that you really don't have to consider a lot of show scenarios, and check each and every effect. So, perhaps James or someone with his software could just tell you what to set your divergence for, given room size and power level, or what to set your power level for, given room size and divergence, and you let it rip. Sure, there are exceptions like, if someone programs a show that parks visible beams in the audience, or if someone creates a show with damn dangerous effects. Theoretically each show would need to be assessed separately. But what you will find might be surprising in that, once you have divergence, power level, and room size dialed in, they hold for most PROPERLY programmed shows.

    Step 3 is to get a scan fail safeguard to make sure that, if someone DOES park a visible beam in the audience, or if there is an equipment failure, the beam will be terminated before any occular hazard exists.

    If there is true interest in this project, I think there should be a kind of open-source effort on a scan fail circuit for hobbyists. Honestly I think that the collective consciousness can come up with something better than some of the commercial solutions out there. Sure, it won't compete with the likes of PASS or James Stewart's system, but I am talking about something as a kind of "last line of defense". Note that this isn't the "first line of defense" as some people think it is. Everything else has got to be right first, and the scan-fail safeguard steps in only in the event of a problem.


    Quote Originally Posted by Jem View Post
    What really hacks me off is that I am a concientious person and I *REALLY* want to do things right, yet there are countless mobile DJ's who are audience scanning in the UK without even giving it a second thought.
    Yes, exactly. I have seen the same thing here in the US, at raves. This is happening kinda "underground" here... People just don't know is the problem. But the more people who find their way to PL, and ILDA, and more awareness being spread by James Stewart and people who attend his classes, the better.


    Quote Originally Posted by Jem View Post
    I haven't done any audience scanning so far as i'm not fully conversant, nor comfortable with working out the MPE's for all the different effects that can be produced in LivePRO. Perhaps that's because I work in Optics and have a conscience, it wouldn't look good if I screwed someone's vision up.
    Really we can discuss all of this here, but the best thing woudl be to attend a class. Perhaps there could be a kind of "introduction to audience scanning" class put on at an upcoming PL meeting?

    In any event, I hope you can see that there are those of us who ARE pretty open about this stuff. Pangolin has always been that way. And James certainly does his part to spread the gospel -- including his participation in this discussion, as well as putting on classes in UK.

    Now let me respond to some other comments .

    Quote Originally Posted by JoJo View Post
    I understand that some companies try to promote their high professional systems here
    Or not .



    Quote Originally Posted by JoJo View Post
    , but the question was about a scan fail detection system, not a system to make shows "safe".
    Right. That's how this discussion started. But both James and I see how people can think that, gosh, if I only had the scan fail circuit, then my projector would be "safe". So yes, this topic has diverged a bit (no pun intended), but into a much more informative area.



    Quote Originally Posted by JoJo View Post
    Our system is microcotroller-based, but it works great.
    Are the schematic and source code available for peer review? If not, then how does anyone else really know that it "works great"? Should we all just take your word for it?

    And to me, here is a real bottom line question that can be asked of literally anyone who is selling a safety solution of any kind. If something goes wrong, and you are dragged into a court of law, is the vendor prepared to stand next to you and defend you? Is the vendor prepared to demonstrate how it is that their safety system (whatever it is) is, to the greatest extent possible, infallible? And is the individual or company frankly rich enough to afford such a venture? Maybe hobbyists don't need to ask this question, but if you are doing serious work, to me, this is an entirely valid question and one that deserves answering.

    Note that if anything lands in a court of law, it's going to go through a lot of scrutiny. It sure would be nice if the safety system has already gone through such scrutiny to begin with... Remember, in the end, you get what you pay for... (but I digress)


    Quote Originally Posted by JoJo View Post
    I designed the first kind of this safety ('safeguard' from Medialas) 1997. At a time, nobody cared about such a thing.
    Really? Nobody? Are you sure about that?

    Pangolin funded a study in 1996, by a professional research firm whose clients included Hughes, Boeing, and countless other high-profile firms. The study was to discover exactly how many audience-scanning-related injuries there were. Pangolin and LSDI also did a lot of work in laser safety software exploration as early as 1997, and hardware work before then. And of course scan-fail safeguards have existed in the US for a very long time, and one was installed at Disney's Epcot Center perhaps as early as 1986 by Laser Media (although not for audience scanning as we know it). So are you sure that "nobody cared about such a thing"?


    Quote Originally Posted by JoJo View Post
    On the other side, you can try to make your show absolutely safe by spending thousands of $ in products, nobody has seen in practical use until now.
    Really? Nobody? Are you sure about that?


    Quote Originally Posted by JoJo View Post
    And nobody ever has seen the result of a safe show, using such a system (except maybe the developer).
    Really? Nobody? Are you sure about that?

    How about what was done for Pink Floyd here in the US? I think a lot of people saw that, including some of the PL members here. I seem to recall a few discussions about it...

    And how about the three- or four-day ILDA Laser Theater at the last LDI in Orlando, where each and every day, we showed safe audience scanning. Heck, it was enough to make Lothar Bopp himself sit up and ask questions .

    There have been other high profile uses for popular vocalists as well. And you will be seeing a whole lot more news about it too.

    So are you sure that nobody has seen this in practical use?

    And how about the work being done by James Stewart's close knit group of users? Are you sure that they are not seeing safe shows?

    Are you absolutely sure of that which you speak?

    Best regards,

    William Benner

  9. #29
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    Hi guys

    I'm glad to see so many on PL are very conserned about making lasers and the shows we do with them as safe as posable. After reading all of the replys on this thread i've come to the conclusion that the only safe laser shows in venuse of the likes of night clubs are those that don't scan the audience.

    Thakyou to Kevin & James for informing me of the correct safe viewing distences for the lasers I mentioned ealyer. The guide sheet I got with the laser I bought a few years ago is heading for the shredder.

    Getting back to scan fail detection systems I would like to hear more about other options and prices for systems that us hobbyist can look at.

    Carl

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    Thanks Bill

    Great reply and I truly appreciate your comments

    I attended the LaserVisuals course about 12 months ago and have a lot of respect for James and his knowledge. I am always eager to learn and will always give a willling ear to anyone who is prepared to teach.

    What we really need is for you to come over to the UK and enlighten us, perhaps you could get together with James and get something organised

    Cheers

    Jem
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

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