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Thread: Radiant Electronics X4 3.7W Laser Power Meter

  1. #1
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    Default Radiant Electronics X4 3.7W Laser Power Meter

    How is the Radiant Electronics X4 3.7W Laser Power Meter at reading emissions at the low end of the scale, such as MPE for audience scanning?

    Anyone rely on this low-cost meter to keep people safe?

    Wes

  2. #2
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    It's fine for what it is, but what it is not is a high accuracy low power high speed power meter. It is completely unsuitable for testing MPE.

  3. #3
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    As a follow up question, you're mentioned that you're in California and you were shopping around for chinese import lasers. Is your interest in MPE for your own safety when enjoying this projector in the comfort of your own home, or is this for the purpose of audience scanning?

  4. #4
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    Can you suggest an affordable LPM that is suited for measuring MPE?

    I don't think I would have as much need to measure MPE if I were simply enjoying the laser in the comfort of my own home. I am trying to learn as much as possible about laser safety before I consider exposing anyone to audience scanning.

    I am working off of Murphy and Makhov's proposal (http://www.laserist.org/files/audien...iew_latest.pdf) as well as other ILDA safety docs.

    W.

  5. #5
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    All I'm going to say on this is to just be aware that beyond the safety component (Which is of paramount importance and is far more complex than sticking a power meter in the scan field) you also have to consider the legal implications of what you're doing, particularly if the display is taking place on University property. Best of luck to you.

  6. #6
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    Please feel free to point me to sources. So far I've been focusing on the safety aspects (measuring/calculating MPE, scanfail circuitry, good show design, etc). Next step after that is to tackle variance, legal, and any insurance issues. I know that many of the people on photonlexicon make their living playing with lasers, and I'd be grateful if people could point me to resources for learning about any and all of these topics.

    Wes

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    If this is something you are really interested in exploring, I'd contact X-Laser and discuss their Polaris system. Other than than, the co-author of that paper you cited, Greg Makhov and his company, LSDI are about the only sources you will find to be able to get into legal, safe audience scanning if you reside in and plan to do shows in the United States.

  8. #8
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    Wes most of the sensitive meter heads seem to have quite low power handling capabilities and the vice versa. The largest one I found with a 1mw resolution when I looked around the common brands, was 2W max power capability. I'm not saying that's definitive. It just seems to be the trend. High power handling and high sensitivity don't seem to go hand in hand. In fact all of the heads I saw over 2W capability had a resolution of 10mw or above, which is a disaster for MPE purposes.

    However, one of the things to remember, is you don't need a head capable of handling your laser at full power as you can simply reduce the brightness before you start measuring. So long as you remember to apply a BAM of sufficient percentage brightness reduction as to be safe for the head, before starting to take measurements you should be fine with a lower rated head. You can always start at the lasing threshold and adjust upwards if in doubt.

    There's a difference between a meter to measure total power and a meter for MPE purposes where resolution is more important than ultimate power handling capability. Remember you're only trying to get to a max of 10mw cm2 (less without a fast scanfail), so you don't need to be blasting it with 4 or 5W from X feet.

  9. #9
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    I think the whole issue of an audience scanning variance is likely to be the over-riding factor here
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    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

  10. #10

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    Quote Originally Posted by wmodes View Post
    How is the Radiant Electronics X4 3.7W Laser Power Meter at reading emissions at the low end of the scale, such as MPE for audience scanning?

    Anyone rely on this low-cost meter to keep people safe?

    Wes
    It is not made for that application. TEC based hobbyist meter and should never be used for safety measurements.

    If you need to measure low powers a thermal laser power meter (hobbyist or professional) is not the type of LPM for you. An optical LPM is much better suited for reading low powers.

    Most thermal meters from Ophir and Coherent are rated at a 10mW-20mW minimum power and even at those powers small heat sources or air flow can throw the readings by a couple milliwatts.

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