Holiday Lights and Laser Dangers

John Huntington’s Blog has covered a lot of holiday light displays over the years. Brooklyn’s Holiday Light Spectacular is the newest one covered on the blog. It tells about Holiday Light Spectacular display with nice pictures, and also gives details on technology behind the display.

If you want to do your own holiday light display then here are some links to interesting project ideas from around Internet: Control your holiday lights with a magic wand circuit allows you to turn on your holiday bulbs with a wave of the magic wand. DIY Christmas Light Suit project uses LabVIEW to perform sound analysis of a playing music and uses LabVIEW Interface for Arduino (LIFA) to drive various Christmas light strings based on the power level at various frequency ranges. Smart Christmas Tree Lights with JenNet-IP video plays with the idea that “What if every Christmas tree light had an Internet address?”. Don’t forget my older Christmas Lights blog postings.


Light shows are nice to watch, but the technology used in them be can dangerous. Blink-182′s Mark Hoppus’ Retina Damaged by a Show Laser posting tells about the potential dangers of light displays that involve powerful lasers. In video Mark Hoppus Presents: The World’s Most Powerful Touring Laser Blink-182‘s bassist and singer Mark Hoppus talks about how he suffered retinal damage during a show in Milwaukee. In the video, he does a pretty good job of explaining how the laser show process works in terms of protecting the audience and what went wrong in performance. That show used a very powerful 26W Lightwave Lightwave Prism Series laser show equipment (you have read right, that’s watts, NOT milliwatts you normally see in most laser specifications).


Remember that this kind of laser damage to eye is usually permanent. Primary personal hazards of high-power laser exposure are skin burns, blind spots when the laser strikes the retina, and the worst case total blindness. Lasers have been coming back into vogue in recent years on touring concerts, so be careful if you happen to be near them or operate them. Remember Laser Safety. There is also a a growing concern over the increased potential risk of eye damage from high power LEDs as well because intense blue light can cause damage to the retina. Do not stare at lasers or very high brightness LEDs, because doing so may cause permanent damage to your eyes. Remember that lasers can also damage cameras and camcorders, and even video projector chips (DLP).


  1. Tomi Engdahl says:

    Found this cool looking light show web page

    One of the best light shows in all of Japan. It runs for 4 full months (from mid November – mid March). Among other things, there is a tunnel of light, a cloud of lights, one of the major flower display areas is turned into an “aurora”, the lake is lit up with lights, and more.

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  10. Tomi Engdahl says:

    Doing Unsafe Things With A Laser Watch

    [Pierce Brosnan]-era James Bond had a beautiful Omega wristwatch. Of course as with any Bond gadget, it couldn’t just tell time; it needed to do something else. This watch had a laser, and [Patrick] figured he could replicate this build.

    Bond-inspired LaserWatch ( selfmade, including some burning laser tricks)

  11. Tomi Engdahl says:

    Metamaterial Technologies partners with Airbus to protect pilots from laser strikes

    Metamaterial Technologies (MTI; Halifax, NS, Canada) and its optical filters division, Lamda Guard, entered into an agreement with aircraft manufacturer Airbus to validate, certify, and commercialize its laser protection product metaAIR [trademarked]. In 2014, MTI signed its first agreement with Airbus to test and tailor metaAIR, which is a flexible metamaterial optical filter engineered to protect pilots against harmful laser beams aimed at aircraft.

    Laser strikes on commercial aircraft are rising globally and laser pointers are increasing in power and decreasing in price. Lasers can distract pilots during critical phases of flight and can cause temporary visual impairment. In 2015, according to the Federal Aviation Administration (FAA), the number of reported laser incidents nearly doubled to 7,703 in commercial aviation.

    “We know from facts and conversations with clients that cockpit illuminations are real, immediate and increasing in frequency, and metaAIR will benefit our customers,”

    “metaAIR will provide vision protection to pilots in the aviation industry and can offer solutions in other industries including the military, transportation and glass manufacturers.”

  12. Tomi Engdahl says:

    Laser pointer safety regulation status

    Last October, the U.S. Food and Drug Administration (FDA) proposed banning laser pointers that are not red or red-orange by designating green, blue, and other colors as “defective”

    The primary goal is to help restrict green and blue pointers. These currently account for 95% of the 7000+ reported incidents per year in the U.S. where a laser beam is aimed towards an aircraft.

    Pilot illumination is a serious safety concern because bright light can disrupt pilot tasks, can cause veiling glare while the light is on, and can even temporarily flashblind a pilot. This visual interference is potentially hazardous during critical phases of flight: landing and takeoff, low-level flight and hover (helicopters), and emergencies.

    Since 2004, there have been over 55,000 reported laser/aircraft illuminations in the U.S., UK, Canada, Australia, and Italy. Fortunately, none of these have resulted in any accidents, nor in any documented pilot eye injuries. But aviation officials, regulators, and lawmakers are concerned that laser light, in a critical situation at the wrong time, could be “the straw that broke the camel’s back.” For example, Senator Charles Schumer (NY) has called three times for the FDA to take action against laser pointers.

    The FDA told TEPRSSC that it is considering designating all laser pointers from 400 nm (deep violet/near-UV) through blue, green, and yellow to 609 nm (red-orange) as “defective” under 21 CFR 1003.2. This is because such pointers “emit electronic product radiation unnecessary to the accomplishment of its primary purpose, which creates a risk of injury.”

    This would not make possession of current laser pointers illegal at the federal level. It would allow the federal government to ban the manufacture, importation, or sale of new non-red laser pointers. If some professions required specialized pointers, a manufacturer could request a FDA variance, allowing sales to law enforcement or other authorized users. However, the FDA is not set up to allow variances for individual sales. So, a person who wanted to buy a non-red laser pointer would not be able to obtain a newly manufactured laser pointer.

    A key advantage of this rule is that pointers could be controlled by color. A customs official does not need to measure a laser pointer’s power

  13. Tomi Engdahl says:

    A Mechanical Laser Show with 3D-Printed Cams and Gears

    Everyone knows how to make a POV laser display — low-mass, first-surface mirrors for the X- and Y-axes mounted on galvanometers driven rapidly to trace out the pattern. [Evan Stanford] found a simpler way, though: a completely mechanical laser show from 3D-printed parts.

    Mechanical Laser Show
    device that projects a pattern by quickly moving a laser. all mechanical, 3d printed, hand powered

  14. Tomi Engdahl says:

    Many laser-safety eyewear products do not meet specs for shielding light from ultrafast lasers

    High-power ultrafast pulsed lasers are used widely for biomedical applications and imaging, materials processing, industrial micromachining and more. But many laser-eyewear products are not tested with ultrafast lasers and may not be providing adequate protection for the technical workers who depend on them.

    The main reason for this situation lies in the typical test procedures and standard measurements widely followed by eyewear makers to set their product specifications. Those methods use low-power continuous-wave (CW) light sources. As a result, they do not capture many potential hazards of actual high-power, pulsed-laser working conditions. Moreover, end users only infrequently test how their eyewear performs in particular applications prior to deployment.

    Scientists at the National Institute of Standards and Technology (NIST; Gaithersburg, MD and Boulder, CO) and Hood College (Frederick, MD) have published a study of 24 samples of protective filters used in eyewear from five different manufacturers.1 They found that “some of them are good, but some did not perform even close to their own specs when used with ultrafast lasers,” says NIST researcher Ted Heilweil.

  15. Tomi Engdahl says:

    Pulse Train HAT Controlling Laser Light Show Raspberry Pi

    Pulse Train HAT controlling laser light show with Raspberry Pi, using PWM and galvanometer scanners.

  16. Tomi Engdahl says:

    Teardown: What’s Inside a Christmas Laser Projector?

    Given how popular they are, I was surprised to see a lone Home Accents Holiday Multi-Color Light Projector on the clearance rack at Home Depot for around $14 a few days after Christmas. This was a 75% price reduction from normal MSRP, and right in that sweet impulse-buy price range. Let’s see what’s hiding inside!

    This particular projector isn’t much different from other’s I’ve seen, except for the fact that it actually has three lasers inside. Usually these projectors are just packing red (662 nm) and green (532 nm), but this one has a blue (440 nm) laser as well. Interestingly, there are only two laser apertures in the front of the unit, which means there must be some kind of beam combiner inside that’s allowing two of the lasers to shoot through one window. Presumably it was cheaper and easier to tack a beam combiner into the design than get new cases injection molded.

    The attentive reader might notice from this picture that the lasers are way out of focus: at 3 meters, the spots looked as large as dinner plates. This is easily fixed by using a small pair of pliers on the focusing rings on the front of each laser. 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.

    In fact, once the blue laser was focused I was easily able to burn pieces of paper and punch holes in black plastic. As for the green laser, it is at least twice as bright as my green laser pointer which is labeled as 50 mW. I don’t have the equipment to measure the actual power of these lasers, but it would certainly not surprise me if they are both at least 100 mW.

    Blue Laser Playset

    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. If that’s what you’re after, I’d advise putting the blue laser in the red laser’s heatsink.


    I would suspect that the laser power rating is based on the diffraction grating breaking the beam up. No individual beam is more than 5 mW.

    Personally, I would not open one of these things up. I value my eyesight too much, and I don’t own any laser safety goggles. Do they even make goggles that cal block red, green, and blue all at the same time, without being completely black?

    Good point on diffraction, it could be they come in under the 5 mW FDA guideline because the individual beams don’t exceed that.

    “No user serviceable parts inside.”

    So should we be alarmed that people are waving ~100 mW lasers all over their house and street, while being told that they’re using much safer 5 mW lasers?
    Or maybe the rating was talking about the individual power of each dot, and the beam is being split up 20-odd ways?
    I guess as long as the beam is being diffracted, and not just reflected, it should be fine.

    Are there any usage restrictions on these projectors especially at locations near airports? I’ve seen people projecting them up at trees, which look really cool and all, but I wonder if stray beams could cause issues similar to people pointing laser pointers at airplanes and helicopters.

    Absolutely. Blind an airliner with one and you’re in trouble if caught. It just shifts the charge from intentional to negligent.

    In general using them outside is restricted to people with licenses similar to HAM operators. You won’t really get in trouble by local law enforcement though unless you are caught pointing at traffic or aircraft.

    My guess on that is that the diffraction and focus issues, out of the box, the light coming out of these things would be nothing to a plane overhead. I think they’d be so diffused, I wonder if they’d even be visible if they were pointed straight up in a flight path….

    First of all the beams move about, second they diverge madly (I expect on purpose) and third of all, a stray laser hitting a plane for a second won’t harm it even if it wasn’t so divergent.

    I saw one in a neighborhood this year. At a yard sized distance, one of the colors in the eye was easy to miss and nothing to worry about. It was a little foggy and by moving my head around I could barely see the beams and not at all if I was about 10 minutes of arc (3 mrad) off the axis.

    A lot of these projectors didn’t get sold this XMAS. I think our local hardware chain overstocked big time.

    Mr. Christmas Programmable Lite-Write Laser Show projects images, messages and has music output. They were half price after XMAS and come with an LCD key-pad to program your own message. Must have some sort of X and Y beam control.

    The green laser is probably DPSS which I think is still cheaper than direct injection green. DPSS is pretty critical when it comes to internal temps to operate efficiently. Not only is there and issue with the temp that the SHG crystal wants to be at, but the Nd:YVO4 crystal itself is wavelength dependent and the diode wavelength will change with temperature.

    I bought a similar unit from a DJ equipment place last fall, as disco lighting for my wife’s (redacted)-th birthday party. It is just red-green, but has the remote control and was music activated. This unit was a bit more expensive and has a better case than the Christmas ones… but I’ll bet it’s got pretty much the same mechanisms inside.

  17. Tomi Engdahl says:

    eBay laser pointers are DANGEROUS!!!

    You’ll shoot your eye out kid! But seriously, that eBay laser that was sold to you as 5mW is likely MUCH stronger. Now obviously I love high powered lasers, but I don’t like when something that is sold as “eye safe” is actually a very dangerous laser.

  18. Tomi Engdahl says:

    World’s Largest Laser Show by ER Productions at LDI 2017 (4k)

    This timecoded laser demonstration by ER Productions featured over 300 laser projectors, setting the Guinness World Record for largest laser show.

  19. Tomi Engdahl says:

    Laser Show – Armin Van Buuren (Mirage) – Pangolin and ECS

    Laser show made using Pangolin Quickshow by Emile Chauvin

    11x ECS 3000 RGB full diode

    600mw 637nm – with 4 diodes
    800mw 520nm – with 1 diode
    1600mw 445nm – with 1 diode
    PT 40 40Kpps Scan

    2x FB3 and pangolin Quickshow

  20. Tomi Engdahl says:

    China first naked eye 3D lighting art show

    Hi-Ltte the first naked eye 3D visual art light show. Points, lines and surfaces presents a perfect color rendering space. 6 minutes 28 second music,138 pics Rambo-Legend,148 Sqm P3-LED display,318 CUE showed the art.

  21. Tomi Engdahl says:

    Hi-Ltte New design 2017 lighting show More professional and Fantastic ! Rambo Knight sharpy Beam LED

  22. Tomi Engdahl says:

    Kvant Laser Show – Prolight+Sound 2015, Frankfurt

    50 KVANT laser systems were set in circular configuration to perform many new and innovative laser effects. In conjunction with other visual media and strong dance

  23. Tomi Engdahl says:

    Kvant Laser Show – Prolight+Sound 2017, Frankfurt

    It was a multimedia show packed with many new technologies and beautiful effects which nicely coupled with lasers together.

    Mirror family laser show – Michael Jackson tribute performance

    KVANT created a show in cooperation with Mirror family, it’s packed with great amount of laser lights and brilliant dance performance.

  24. Tomi Engdahl says:

    Mirroring Kingdom ( Light Laser Mirror Show)

  25. Tomi Engdahl says:

    Limitless 3D – 2013 1st Place International Award Winning Laser Show

    Winner of the 1st place 2013 ILDA award for Multiple Projectors Beams and Atmospherics Laser Show category.

    D1000 RGB LASER diode cirkelshow

  26. Tomi Engdahl says:

    pure diode 3W demo

    Laser Show – Funkin Matt – Elephant – 17 RGB laser – 47W total power !!

    Laser show made using Pangolin Quickshow by Emile Chauvin

  27. Tomi Engdahl says:

    QuickShow – Easy-to-use Laser Show Software and Hardware for the Entertainment Industry

  28. Tomi Engdahl says:

    Hi-ltte 2016 330W 3in1 beam spot and wash moving head light.most beautiful、wonderful show!

  29. Tomi Engdahl says:

    Hi ltte 7R beam and 15R sharpy beam moving head light

  30. Tomi Engdahl says:

    World’s Largest Laser Show

    Watch highlights from our world record attempt for the largest laser show on earth at Live Design International (LDI) in Las Vegas on 18th November, 2017.

    World’s Largest Laser Show by ER Productions at LDI 2017 (4k)

    This timecoded laser demonstration by ER Productions featured over 300 laser projectors, setting the Guinness World Record for largest laser show.

  31. Tomi Engdahl says:

    Laser show in Disney California for “Tron Legacy” movie release

  32. Tomi Engdahl says:

    Laser projector ditches galvanometer for spinning drum

    Laser projectors like those popular in clubs or laser shows often use mirror galvanometers to reflect the laser and draw in 2D. Without galvos, and on a tight budget, [Vitaliy Mosesov] decided that instead of downgrading the quality, he would seek an entirely different solution: a spinning mirror drum.

    He fires a laser at a rotating drum with twelve mirror faces, each at a different adjustable vertical angle. The laser will hit a higher or lower point on the projection surface depending on which mirror it’s reflecting off – this creates resolution in the Y direction.

    Alpha-Numeric Laser Projector

  33. Tomi Engdahl says:

    Science Shows Green Lasers Might Be More Than You Bargained For

    This may come as a shock, but some of those hot screaming deals on China-sourced gadgets and goodies are not all they appear. After you plunk down your pittance and wait a few weeks for the package to arrive, you just might find that you didn’t get exactly what you thought you ordered. Or worse, you may get a product with unwanted bugs features, like some green lasers that also emit strongly in the infrared wavelengths.

    Sure, getting a free death ray in addition to your green laser sounds like a bargain, but as [Brainiac75] points out, it actually represents a dangerous situation.

    He explains that the paradox of an ostensibly monochromatic source emitting two distinct wavelengths comes from the IR laser at the heart of the diode-pumped solid state (DPSS) laser inside the pointer. The process is only about 48% efficient, meaning that IR leaks out along with the green light. The better quality DPSS laser pointers include a quality IR filter to remove it; cheaper ones often fail to include this essential safety feature.

    It’s a sobering lesson, but an apt one given the ubiquity of green lasers these days. Be safe out there

    “Lots of hidden dangers, thanks for alerts, too many ppl not taking simple safety assuming low power label means low power, its a very messy market place…”


  34. Tomi Engdahl says:

    Laser + mirror + sound

    A laser shining on a mirror driven by a speaker creates cool patterns.

  35. Tomi Engdahl says:


    Some green laser pointers not only emit a bright green beam but also invisible radiation at a hazardous level!
    How do we make invisible radiation visible and how do you test your laser for this? Let’s find out!

    You can see infrared?!? Failing safety glasses

  36. Tomi Engdahl says:

    DIY Laser Made from Thin Air!!

    It turns out that regular old air makes a laser beam when you blast it with high voltage! In this video I demonstrate one of these lasers as well as talk about how it works.

    The laser that I built in this video is an example of a TEA laser, where diatomic nitrogen is the lasing medium. There have been plans for DIY TEA lasers around since the 1970s, so I am definitely not the first one to do this!

    Here is a great resource for building a nitrogen TEA laser, and this was the first resource I read when I wanted to build my own:

  37. Tomi Engdahl says:

    Destructive Testing of Laser Goggles!

    Find out which goggles to use with your high powered laser and also see how those eBay goggles hold up to a direct hit with a laser!

    In this video I broke out some of my huge lasers and blasted some goggles from ebay as well as survival lasers.

    The ebay goggles gave mixed results. Some did better than I expected, and others failed miserably. Although just the fact that one pair passed, doesn’t mean you should trust some random seller with your eyesight!

    I’ll always recommend survivallasers for their safety goggles, and I’ve used their goggles for years.

  38. Tomi Engdahl says:

    Amazing White Laser Experiments!!!

    Laser р0rn!! Here I build a full color RGB white laser, as well as experiment with the beam using prisms and mirrors.

    In this video I build a full color RGB laser using red, green, and blue lasers. I use an analog driver based on the LM317, and combine the beams using an X-cube. The resulting laser can make white, yellow, aqua, magenta, purple and many other colors. The white laser beam can then be split back up with prisms and diffraction gratings, as I show in the video. I then build a white laser based on just two colors, yellow and cyan, and then in the end of the video I show some TRIPPY effects with a laser time tunnel.

  39. Tomi Engdahl says:

    Crappy Christmas “Laser Shower” projector teardown

    A look at a cheap laser Christmas projector, with a mystery unnecessary chip on the PCB.

  40. Tomi Engdahl says:

    Looking at a cheap green laser

    A look into the control electronics for a cheap DPSS green laser module, with a diversion into optical measurements.

  41. Tomi Engdahl says:

    Green Lasers: What Can Certain mW Do?

    This video compares some of the most common power outputs of green lasers you can buy these days. I compare the difference in visibility and burning between 5mW, 15mW, 35mW, 50mW, 100mW, and 150mW.

  42. Tomi Engdahl says:

    James Bruton’s Laser Sound Equalizer

    His machine takes in audio signals via an MSGEQ7 graphic equalizer, which passes seven frequency readings on to an Arduino Mega. Dots from seven laser pointers that power the machine are turned into lines using a spinning mirror assembly, but in order to make the height of the lines proportional to actual sound, a few other tricks were needed.

  43. Tomi Engdahl says:

    Dangerous Christmas Laser Show Upgrade – 1000x Stronger

    Ever see those Christmas light show things at the store and think they would be a lot cooler if they were 1000 times stronger? I did at least, so I made it happen.

    In this video I tear down a cheap laser projector that I bought at Farm and Fleet, and do a bunch of mods to it so I could jam in a 5W blue laser diode. The puny little power supply couldn’t handle the huge laser, so I had to make a new driver from scratch. Plus, the original optics melted almost immediately, so I had to upgrade them so they wouldn’t explode after being hit with 1000x their rated power.

  44. Tomi Engdahl says:

    Amazing White Laser Experiments!!!

    Laser р0rn!! Here I build a full color RGB white laser, as well as experiment with the beam using prisms and mirrors.

  45. Tomi Engdahl says:

    eBay laser pointers are DANGEROUS!!!

    But seriously, that eBay laser that was sold to you as 5mW is likely MUCH stronger. Now obviously I love high powered lasers, but I don’t like when something that is sold as “eye safe” is actually a very dangerous laser.


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