This 40 watt laser shotgun somehow isn't illegal to build

By Shawn Knight · 16 replies
Jun 9, 2015
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  1. Late last year, we shared a story of a gadget enthusiast that built a fully functional laser watch. While impressively cool, the invention pales in comparison to this laser shotgun that YouTuber “styropyro” recently put together.

    The 40 watt gun is comprised of a blue laser diode array that shoots eight parallel five watt beams. It’s strapped to a massive passive heatsink, is powered by a lithium polymer (LiPo) battery pack and is regulated by 24 LM317 drivers.

    As styropyro points out, dangerous is an understatement. Watch as he ignites all sorts of objects with ease. Very cool!

    Found is a TechSpot feature where we share clever, funny or otherwise interesting stuff from around the web.

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  2. VitalyT

    VitalyT Russ-Puss Posts: 3,660   +1,948

    Same policy as having a bottle of booze in the car, which is fine for as long as it remains unopened.

    Just so, before Hiroshima, it was perfectly legal to have an atomic bomb in your household ;)
  3. stewi0001

    stewi0001 TS Evangelist Posts: 1,681   +1,079

    I would love to use this for starting my grill and fireplace.
    Julio Franco likes this.
  4. this! ^^ :D
    Julio Franco and stewi0001 like this.
  5. VitalyT

    VitalyT Russ-Puss Posts: 3,660   +1,948

    It can start a grill and a fireplace, yours and of your neighbors' :)
    Julio Franco and stewi0001 like this.
  6. trparky

    trparky TS Addict Posts: 246   +115

    I like this comment on the video...
    "Do you want Supervillains? Cause this is how you get Supervillains!"
  7. lipe123

    lipe123 TS Evangelist Posts: 718   +236

    Meh unless you actually point it right into someones eye its fairly harmless, it takes quite a while to warm up something to dangerous levels so moving targets would be totally safe.

    It does look pretty cool though, wish he cleaned up the messy wire job better
  8. Seventh Reign

    Seventh Reign TS Booster Posts: 131   +65

    You obviously didnt actually watch the video. Ignition was virtually instantaneous. With the correct focal length, even a moving (human) target would not be able to get out of the way in time.
  9. Spykezxp

    Spykezxp TS Addict Posts: 294   +73

    Dr. Evil - "You know, I have one simple request. And that is to have sharks with frickin' laser beams attached to their heads!"

    Step 1: Build Laser
    Step 2: Acquire a shark.
    Step 3: Combine
    BlueDrake, Julio Franco and Hexic like this.
  10. Everything he does in that video can be done with a match. I guess that's why a laser of that power is not illegal.
  11. sTharsdan

    sTharsdan TS Rookie

    If he added some nice laser sounds then he would have something. Otherwise no good.
    Julio Franco likes this.
  12. lipe123

    lipe123 TS Evangelist Posts: 718   +236

    It took a full 1.5 to 2 seconds to pop an inflated balloon just 1-2 meters away. Anything beyond the perfect focal distance will take forever. A magnifying glass in the sun is every bit as powerful as that laser by comparison.
    Saying dumb things like "you obviously didn't watch the video" is just silly don't do it. The only reason that laser is any good is because of the focusing lens on it which limits its use to very short distances and perfectly still targets.
  13. wiyosaya

    wiyosaya TS Evangelist Posts: 1,918   +750

    So a "secret" or two without saying much:

    If each beam is collimated to a fairly small spot size, each beam by itself is enough to start a fire depending on the target material and at a reasonable distance since laser light does not spread significantly when collimated.

    This is not a 40-watt shotgun. It is an 8 x 5-watt array. For it to be a 40-watt shotgun, the beams would require phase conjugation which is what the recent military laser uses to produce a 30kWatt beam from multiple, lower power fibers. In this "shotgun" each beam is probably partly cancelling out the power of each other beam since the array is not phase conjugated. Phase conjugation is generally not within the economic reach of someone like this guy.

    Nevertheless, it might be some dolt like this guy who ends up making it illegal for the basement experimenter to build something like this - especially in the climate of this day and age. I am sure he thinks it is cool, but is he doing anything even remotely useful or scientific in nature with this? I highly doubt it.
    Sancticide likes this.
  14. MilwaukeeMike

    MilwaukeeMike TS Evangelist Posts: 2,886   +1,222

    The headline is just clickbait. It's legal to build a full-sized medieval trebuchet... it's legal to buy a flame thrower for burning out weeds, it's legal to buy fertilizer that can blow up a building.... and on and on...

    Like anyone knows what any of that means.

    What even cooler than setting paper on fire? This laser casts it's own shadow! Although I guess that's proof of it's wasted power. If all the light were focused forward, it'd be even stronger.
    Sancticide likes this.
  15. Capaill

    Capaill TS Evangelist Posts: 451   +180

    I thought it wasn't possible to see the beam from a laser (sorry Star Wars fans). I guess he has a filter on the camera?
  16. Why is everything that "might" be suspected of becoming a weapon need to be made illegal? Should Fists be made illegal? Will we all be forced to wear Socker Boppers over our hands in public so cowards will feel safe? Taglines like this article that pander to the fearful and eternal victims are a disgrace.
    Sancticide likes this.
  17. wiyosaya

    wiyosaya TS Evangelist Posts: 1,918   +750

    I was thinking that myself. What is likely happening is that the oxygen (or another gas) in the air itself is fluorescing as you can see the beam in blue and green lasers on other youtube videos.

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