A comprehensive resource for safe and responsible laser use
In a January 22 2018 Hackaday post, Tom Nardi purchased a “Home Accents Holiday Multi-Color Light Projector” from a hardware chain on clearance, marked down from $56 to just $14.
He removed the cover with four screws and found the parts inside used connectors instead of solder: “It’s like they wanted us to strip it for parts.”
The lasers were defocused inside. “…[A]t 3 meters the spots looked as large as dinner plates…. Once focused, it becomes pretty clear that these lasers are quite a bit more powerful than the <5 mW listed on the product’s warning sticker.”
The green and blue laser diode modules inside the holiday projector
Nardi noted that the blue laser, when focused, was “easily able to burn pieces of paper and punch holes in black plastic.” He also estimated that the green laser was “at least twice as bright” as a laser pointer he owns that claims to be 50 mW: “…it certainly would not surprise me if they are both [green and blue] at least 100 mW.”
Nardi writes: “If your biggest take-away from this post is that the Home Depot is selling a 440 nm laser you can use to burn stuff, I certainly don’t blame you.”
From Hackaday. LaserPointerSafety.com has a page with more information, including measurements of the beam output of a Star Shower projector, here.
Commentary from LaserPointerSafety.com: In fairness to Home Accents, the FDA-required warning sticker has to do with the laser power of the unopened unit in its factory configuration. Class 3R (IIIa) laser projectors like this are not allowed in the U.S. to be over 5 mW output power. It may be that after going through the holographic diffraction grating that creates the stars, that the Home Accents projector meets Food and Drug Administration requirements for user access to laser light.
It works by putting a standard pen-type laser pointer between two cams. Cranking a handle turns the cams which bounce the laser pointer up/down and left/right to create projected patterns:
By using different cam shapes, different patterns can be projected:
Instructions and plans are available online, including Thingiverse 3D printing files.
Stanford noted “At this point I think it is unlikely I will continue the project. But if I did, here’s what I could do:” He then listed adding blinds to make discontinuous patterns, making the device motor driven, and adding a web service to make it easier to create new cam patterns.
From Evan Stanford’s Hackaday.io page, posted in mid-June 2017
Michael Reeves’ tongue-in-cheek narration states “…it’s really doing its job of lasering me in the eye which is the real innovation here. To my pleasant surprise I found that this machine also solved another of society's problems; the fact that you're not seeing little tiny dots in your vision all day long. I know where to go when I wanted to see little dots, now I can't focus on anything.”
The laser in the video looks substantially more powerful than the U.S. FDA limit of 5 milliwatts. (However, it can be difficult to estimate laser power from a video. For example, the camera may be more red-sensitive than human eyes which might explain why the beam seems so large and bright.)
Anyone doing this should be aware of the problem of laser pointers often being more powerful than the label states, and more powerful than the U.S. limit of 5 mW.
Fortunately for Reeves’ vision, the laser is mechanically aimed by two devices that move it left-right and up-down. This makes the aiming relatively slow and lagging the facial recognition, so the beam can be dodged much of the time. He moves to avoid the beam, and is hit in or very near to an eye about once every couple of seconds.
The screenshot below shows the camera (blue arrow) and a laser module mounted on two servos (yellow arrow).
As befits a student budget, the housing is an old pizza box. Reeves wrote the facial recognition and aiming program in C#, using Emgu CV, a .Net wrapper for the OpenCV computer vision library.
In about a day, the video received 80,000 views as well as being featured at tech blog The Verge.
From The Verge. Original YouTube video here.
UPDATED April 19 2017: Michael Reeves told C/Net “My eyes are fine. A lot of people seem concerned about that, which I admit is warranted. I used a 5 mW laser diode, and never had it in my vision for more than a fraction of a second."
Anthony started by harvesting lasers used in DLP video projectors, such as the Casio “LampFree” series:
He purchased four broken projectors, each with an array of blue laser diodes totaling 50 watts, to get a grand total of 200 watts of laser output. He then used knife-edge optical components to help superimpose all the laser beams.
When energized, the beam is immense and powerful:
The highest (most hazardous) laser classification is Class 4, which starts at 500 milliwatts (0.5 watts). Such lasers can cause instant eye injury, skin burns and can burn materials. Anthony’s 200 watt laser is 400 times more powerful than the 0.5 watt limit where Class 4 begins.
In the video, Anthony says “this feels like I’m holding a bolt of lightning in my hands. This is definitely my new favorite toy.”
Adding a magnifying glass to the end focuses the beam onto a spot that can almost instantly burn a block of wood:
When operating the laser, Anthony wears a welder’s mask with laser goggles fitted. This prevents potential retinal burns caused by looking at the concentrated laser light. Below he is shown with the laser and mask.
At the end of the video, he says “I'm glad to have finally finished this beast because that means I can start working on some of my other projects, and in the coming months I have a lot of crazy stuff planned including impulse lasers that peak in the megawatts as well as explosively pumped lasers, so I'm looking forward to that….Until the next time, stay safe and happy lasing!”
Drake Anthony is a 23-year old senior at Southern Illinois University, who has been accepted into the University of Rochester PhD program. In a Feb. 2016 newspaper profile entitled “SIU student turns passion for lasers into potential career”, the author notes that “What really excites Anthony is the science behind the beam.” She quotes him as saying “From a theory perspective, it’s beautiful. It uses physics, it uses quantum physics, chemistry, good things of math, engineering. It’s just this conglomeration of all the best things that humans have come up with.”
From the YouTube video “My Homebuilt 200W LASER BAZOOKA!!!!!”, posted June 28 2016
The hobbyist, with the username “styropyro,” wrote on YouTube: “Just finished building my 40W(!!!) laser shotgun!!! The output of this laser is complete insanity, and is made up of 8 parallel 5W laser beams totaling to 40W. The parallel beams are manipulated with lenses, sort of like how a choke modifies the spread of a shotgun blast. The massive diode array is powered by a huge lithium polymer battery pack (capable up dumping 250A) and the laser array is regulated by a whopping 24 LM317 drivers. This is definitely the craziest thing I have ever built, but I hope to beat this invention with something even crazier before too long.”
In the video narration, he said “I just built something so crazy that I’m almost afraid to use it” and “There is no, no good reason for anybody to own something this powerful. But because it wasn’t illegal for me to build, I decided to build it anyway.” The video then goes on to show the beam popping balloons, and burning paper, a ping-pong ball, and other materials.
Styropyro had previously posted other videos with titles such as “Homemade Lightsaber!?! MASSIVE 3W Handheld Laser Torching Stuff!!”, “My Homemade 6W Laser Sword!!!” and “Homemade Death Ray Laser DRONE BOT!!! Remote Controlled!!!”
From Gizmodo. Thanks to Patrick Daniel Murphy for bringing this to our attention via Reddit.
The technique is to look in the desired direction with the red aiming beams on, then to switch on the blue beams while looking at the desired target. The glasses have a lens that attenuates blue laser light, so that the user is protected in case of any reflected blue beams.
The two blue beams emitted from Priebe’s glasses, each roughly 1 watt, can burn cloth and pop balloons.
His inspiration: Cyclops’s 2-gigawatt “optic blast,” which is red in the Marvel comic books.
An online YouTube video shows Priebe’s laser glasses in action:
Due to the inherent danger of head-worn lasers, Priebe is not making additional glasses and he is not offering plans for others to build their own.
Priebe has previously built custom laser gadgets such as a replica of Iron Man’s palm-mounted repulsor ray projector, a laser “Gatling gun” with six rotating 1.4 watt blue beams, and a laser gun that emits a non-visible 1 megawatt pulse.
From Gizmodo. Original video posted by AnselmoFanZero.
Click to read more...
Lasers in the 1 watt range have been widely available since the mid-2010 introduction of the Wicked Laser Spyder III Arctic blue laser. This is the first handheld 3 watt laser that LaserPointerSafety.com has been aware of.
Click to read more...
This is not the first time such a project has been done. In 2007, Kip Kedersha (“Kipkay”) posted a YouTube video showing how he bought a surplus Playstation 3 laser diode for $45 and a Star Trek toy for $30, in order to make a laser-emitting phaser.
A Huffington Post story has the 2012 video, as well as links to earlier videos and detailed build instructions.
From Reddit via the Huffington Post
Hobbyist Patrick Priebe’s inspiration was the comic book character “Iron Man”, who has “repulsor rays” in the palms of his armor’s gloves. Priebe’s device is self-contained, with the battery in a case that wraps around the back of the hand. Simply flexing his hand triggers the beam to fire.
Priebe’s 1 watt, 445 nm blue laser beam ignites a match
His inspiration: Iron Man’s repulsor ray glove, as seen here in the motion picture with Robert Downey, Jr.
Priebe made a number of versions. He is selling limited numbers (not mass-produced) of kits and assembled gloves on laser pointer forums for $200-500 depending on the version.
From Popular Science and many other sources. Details on the construction are at Hacked Gadgets. Videos of the device in action are here and here.
This differs from most pointers and handheld lasers, which use lasers that emit continuous light. This one emits a single, strong pulse each time the trigger is pulled. It is “enough to punch holes in plastic sheets, scorch wood, and pop balloons from several feet away” according to Dvice.com.
The maker, Patrick Priebe, posted a YouTube video showing the gun in action. He also was offering it for sale. According to Priebe, the gun uses a Q-switched Nd:YAG laser. It takes four seconds to charge the capacitor; the gun then fires a 100 nanosecond, 1 megawatt burst of infrared 1064 nanometer light. The gun took Priebe about 70 hours to build. His YouTube page offers to help others wanting to build their own laser gun.
SAFETY NOTE: Because the laser emits an invisible pulse, it would not be a visual interference hazard to aircraft (e.g., it could not cause glare or flashblindness). At close range the Q-switched pulse would definitely be an eye hazard, causing an explosive steam “pop” on the retina rather than the relatively slow burn of a continuous-wave laser. LaserPointerSafety.com has not done an analysis to determine the “safe” distance, beyond which it would not pose an eye hazard to pilots or others.
From Dvice.com and Hacked Gadgets forum
The hobbyist indicated “I will comply since the things don’t really bring me much money.”
A link to the hobbyist’s post and the text of the letter are after the break (click the “Read More...” link below). For background information on the Casio diode harvesting, see the June 2010 alert.Click to read more...
More than two weeks after the accident, he reports “... there are no identifiable irregularities. I am certain there is permanent damage in the spot, but it is so far out in [my] peripheral vision, that it is just not noticeable. So I have officially ceased worrying about it. Lesson learned.”Click to read more...