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Thread: first laser project for home use

  1. #1
    Join Date
    Dec 2007
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    Default first laser project for home use

    Hi there,

    First of all, what a wonderfull forum this is. The amount of experience here is quite amazing.

    So, I bought Dave's SCANPRO20K and I am about to order a FB3. My goal is to only use this scanner for a hobby and do some shows in my rather small living room.
    Because I like beamshows a lot, you are actually looking at the laser source. (unlike animations where you look more away from the laser towards the wall).
    So I wonder what the minimum (and safe) amount of mw is for a red and a green to at least see something (and yes, i have a fogger!!)

    I'm also gonna use goggles for setting up and aligning the laser. I just hope i dont need them while watching the show. (yes, i like being inside a timetunnel effect )

    I ordered the 50mw green and 100mw red 5V stage laser modules from DealExtreme.
    They also should be able to be ttl driven. (I already have a True 30mw from DX which is love for starpointing etc..).

    I know i dont have to expect quality, but this is almost the least amount of mw that you can get. And the 100$ that it costs is worth the risk. (specially with the low dollar to euro :-) )

    Oh, I also plan to buy some goggles and dichro's from the group buy here, but the guy doesnt seem to respond.

    Thx,
    Highvolt

  2. #2
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    Pflugerville, TX, USA
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    Default

    I also use mine for home. I have 50mw green, 180mw red, 70mw blue. This is coming out of the modules. I am not sure what the levels are when the exit the scanner mirrors. These levels give me a perfect color balance and are plenty for home use. In fact, sometimes I take it outside and broadcast 300ft or so away and can still see the images just fine. I can't see the beams in clear air but with just a touch of fog the beams are nice.

  3. #3
    Join Date
    Mar 2007
    Location
    Rotorua New Zealand
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    Default

    Hi...

    In some ways your timing to ask this could not be better.

    There has been some very good threads on laser safety and amount of exposure that may or may not be acceptable.

    Your comment..
    Because I like beamshows a lot, you are actually looking at the laser source. (unlike animations where you look more away from the laser towards the wall).
    So I wonder what the minimum (and safe) amount of mw is for a red and a green to at least see something

    I suggest that you do a search on here PL on laser safety and limits. Also go to the ILDA webiste (www.ilda.org) ..
    Also look at the Pangolin website (www.pangolin.com) you will see some good safety articles on these sites.

    I would suggest you do this homework before you do any more towards purchasing your lasers.

    I am not an expert on the amount of laser light you can safely look at but I can tell you it is very small. There are many factors not just the power to consider.

    The good news is you are here and there are some very knowledgeable people here that can help with your questions I am sure.

    Anyway have fun and stay safe its a great hobby but could be an unforgiving one if mishandled.

    Cheers

    Ray
    NZ



  4. #4
    Join Date
    Dec 2007
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    93

    Talking

    Well, the reason why I ask is because I have the impression that all the people here ALWAYS wear goggles when they do something with the laser, even watching the show. I understand that I need to use goggles when working with single beams and for laser setup. But I still think that a show needs to be watched without...
    See, it's like having sex with, or without a condom... if you trust your wife, sex without a condom is safe and a lot more fun

    I understand the principle of MPE and all that, but it's not very practical for home use, is it. With the same analogy from above, it's like putting the condom under a microscope and look for holes. By that time, my desire is long gone. (and your wife as well)

    So, my personal guideline was that with this amount of power (50+100), a moving beam can be assumed safe enough for home use. As long as the scanned pattern is for example not smaller then a cokecan, and any single beams are above the audience heads.

    Here in Belgium (and the surrounding countries) you would be amazed what you see at parties and clubs. They probably know MPE levels, but i dont think anyone is checking it. I guess they boost it 4 times because they know the max mpe is a worst case scenario number with build in safety margins.

    If there is one thing missing on the forum, it is a reasonable safety guide for newbies like me. It scares me that people on ex. LaserPointerForums buy +200mw pointers for burning only. Hell, even my 30mw green pointer is too bright to watch when you point it to a white wall. On the other hand, telling everyone to calculate MPE's and use goggles all the time is imo overkill for home use.
    I call it personal safety mentality.

    Carmangary, can you tell me where you bought these and how much they were ?

  5. #5
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    Pflugerville, TX, USA
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    I bought the 50mw green from Aixiz for about $130. I got the 70mw Blue from Lasever for $400. It was sold as a "50mw" laser but puts out 70mw. Most of the lasers do put out a little extra. I made the red laser with the 200mw 650nm laser diode from aixiz. But, a DVD burner diode would be just as a good.

    The green laser came with a TTL board but I don't use it. I use Robin's die4drive boards for the red and green. The blue laser came with analog modulation already. Analog modulation is the way to go.

  6. #6
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    Mar 2007
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    Rotorua New Zealand
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    Oh boy this is one of those ... "ask and when I get answers that don't quite fit what I wanted to hear I then go to lengths to refute the very questions I was asking on the first place" type threads..

    Firstly there was no intention by me to say what you are doing IS dangerous or wrong merely that some homework is necessary and I was just giving you some pointers to some of that information. Like trying to help ...


    Quote Originally Posted by highvolt View Post
    Well, the reason why I ask is because I have the impression that all the people here ALWAYS wear goggles when they do something with the laser(probably not), even watching the show(I doubt it). I understand that I need to use goggles when working with single beams and for laser setup. But I still think that a show needs to be watched without...
    See, it's like having sex with, or without a condom... if you trust your wife, sex without a condom is safe and a lot more fun

    I understand the principle of MPE and all that, but it's not very practical for home use, is it(Why not ? do your eyeballs change because you are at home rather than at a venue ?.. are your eyes any less valuable than an audience members??) With the same analogy from above, it's like putting the condom under a microscope and look for holes. By that time, my desire is long gone. (and your wife as well) (perhaps the answer is in the matter of balls, eyes and other types !)

    So, my personal guideline was that with this amount of power (50+100), a moving beam can be assumed (oh no ! the assume word) safe enough for home use(why ? can you prove it? if so lets see the math). As long as the scanned pattern is for example not smaller then a cokecan, and any single beams are above the audience heads.

    Here in Belgium (and the surrounding countries) you would be amazed what you see at parties and clubs(it appears to be the case all over the world but does that make it safe ?). They probably know MPE levels, but i dont think anyone is checking it. I guess they boost it 4 times because they know the max mpe is a worst case scenario number with build in safety margins.

    If there is one thing missing on the forum, it is a reasonable safety guide for newbies like me.( if you went to those sites and also did a search here there is loads of information) It scares me that people on ex. LaserPointerForums buy +200mw pointers for burning only. Hell, even my 30mw green pointer is too bright to watch when you point it to a white wall(mmmmm interesting, wonder what thats telling you !!) On the other hand, telling everyone to calculate MPE's and (why again !!).use goggles all the time (I doubt this happens all the time) is imo overkill for home use
    I call it personal safety mentality.

    Carmangary, can you tell me where you bought these and how much they were ?

    I am not saying your wrong.. but it seems to me you came here for advice then gone into some slightly "I am justified mode" comparing MPE and safety processes with holes in condoms... well get it wrong in both cases and your screwed that I can vouch for.

    You may do well to look at the threads that are on this site in the last few months about audience safety and you will see this is very far from a simple matter. That is all I was suggesting to you.
    We have some of the best laser brains in the world here (not me by the way) who give their time generously to help us. Why not do them the courtesy of reading what they have said on this very subject.
    Just do a search on PL the information will flood in.

    I would think that if you came here with a view for someone to simply "rubber stamp or approve" your ideas I doubt that will happen.

    Anyway good luck with your project hope it all works out for you.

    Cheers

    Ray
    NZ

  7. #7
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    Jan 2007
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    Florida
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    Default

    OK, looking at the beams (the 'source') and not the wall is my fav too. As long is its above direct eye contact with the beam itself; altho moving is a little better than stationary they're both haz-mat and lost eye when the beam enters the retina..enjoy but when aligning projector and testing I use **very**low power and goggles (some-and-most of the time) and when you crank it up it's awesome but you still have to be extremely careful (especially when entertaining guests in the living-room, and even outside).. Foggy nights are the best Design, planning and care are essential though..
    Last edited by steve-o; 04-26-2008 at 18:26.

  8. #8
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    Cool

    If you're doing beam shows in your home, you'll be hard-pressed to keep the beams 10 feet off the floor. (Unless you have tall ceilings!)

    That said, you can still do beam shows that look great. Just don't let the beams scan you in the eye. Keep them high enough that you'll be out of the beam and you'll be fine. (Or stand off to the side.)

    Of course, this sort of "fly by the seat of your pants" technique would never fly in a public venue, but what you do in your own living room is your business.

    The danger is when the beam enters your eye. If you are going to do this, then you are crowd scanning, and you will be putting your vision at risk. (Yeah, even if it's just in your living room.)

    The MPE calculations you refer to are time-consuming and require specialized gear, but if you're going to park your eyeballs in the beam, you really should do the math first. (You only have one set of eyes...)

    Remember: just because the beam is moving doesn't mean you are safe. And if you don't know a *lot* about laser safety (particularly as it relates to crowd scanning), then you shouldn't be doing it - even in your own home.

    If there is no chance that the beam can enter your eye, you don't need the goggles. You can enjoy the show just fine. But if the beam can hit your eye, you either need to go through the math above, or else wear a pair of goggles.

    Adam

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