DECORATION LASERS | Stronger than you think…


Hi! In this video, I will open up four
decoration lasers and see what’s inside. How do they work?
How powerful are they? I will measure them with a laser power meter since I have a feeling they are way beyond
the power indicated on their labels… Wear laser safety goggles
when messing around with powerful lasers. And do not open them, unless you know
what you are doing. These decoration lasers can be
used for a lot of things But they are intended to be placed in a garden
and project green and red dots onto your house at night. Typically around Christmas, where it is popular
to have houses illuminated with a lot of lights. I have never used mine for
the intended purpose though. I have just bought these over the years
after Christmas, where they were on sale. Often for 50% off. I like lasers, and these are special
since they run on mains electricity, are remote controlled and designed to work in a very wide temperature range for
hours upon hours without overheating. Unlike most laser pointers. They can also be set to blink, light only one laser and three of them even have motion built in
making for a lot of different light functions. Well, in one of them, the motion function is not
working, so I will try to fix that when I open it. The two with a working motion function
have quite different speeds. One is slow. And one is fast. I prefer the slow moving one. Let me know in a comment
which speed you prefer? The four lasers can be divided into two types. The ones with a single aperture for
both the red and the green laser, and the ones with dual apertures.
One for each laser color. Let’s open them up and
see the differences inside. I will start with the simplest and smallest one. A dual aperture type with no motion. There we have it. The green laser on the left
and the red laser on the right. And some double-axis diffraction gratings in front
of them to split the beam into hundreds of beams. The main part of the enclosure is all metal –
working as a giant heatsink for the two lasers. The back is made of plastic. There’s a reason for this as we’ll soon see. There’s an antenna inside for the
radio frequency remote control. The plastic lets the radio signal pass through. Metal wouldn’t. The crystal oscillator is marked 6.7458 MHz, which is the reference clock speed
used in 433 MHz remote controls. Worth noticing too is the unused
third pin on the green laser. It reveals they did not decide to use a photo-
diode as feedback on how the laser performs. They are however sensoring
something near the green laser. Most likely the temperature to make sure the green
laser is not overheating when turned on for hours. Other than that there’s not much of interest. There is a connection for a motor, but they did
not implement the motion function in this laser. It is however clearly the
brightest of the four lasers. Maybe because the extra optics for the
motion function lowers the output? Maybe because they put stronger lasers in it? We will know, when I test them
on a laser power meter later. Let’s move on to some,
that do have the motion function. The two single aperture models look very similar
on the outside and have similar functions. Except the black one does not have remote control
and the motion function seems broken. If I open the working one first, I may be
able to figure out how to fix the broken one. Hm, it does seem to have a second aperture.
It is just taped over. This looks way more interesting than the first laser. There’s a big heatsink for the green laser and
a motor with a gearing house in front of the lasers. The laser beams are sent through the same aperture
using a technique from real show lasers. The green laser beam passes through
a dichroic mirror that is transparent to green. But it reflects the red laser light. Nice detail in such a cheap laser. The motor is spinning a diffraction grating. This makes the beams spin before they are sent through a second, static
diffraction grating sitting in the aperture. A simple setup giving the nice motion effect. In the heatsink I spot
a temperature sensor again. It is marked NTC on the PCB
revealing they use an NTC thermistor. But I also spot something else with much thicker
wires sitting in the heatsink – marked RES. This confused me until I realized: Thicker wires are used for something
that draws a lot of current. A heating element. Yep, inside the heatsink meant
for cooling the green laser they put a heating element to warm it up. Seems illogical until you remember these lasers
are designed to work outside in a cold winter. And if you have seen my video
‘Lasers drift with temperature?’ where I put a green laser
pointer in the freezer and test it you know they do not like freezing temperatures. So they need to heat up the green laser
in cold weather, which can take some time. On the PCB I notice the antenna for the
remote control and a missing connection. It has something to do with the second
aperture as we’ll see in the next laser. Will this be exactly the same inside? No, there are differences. It also has the second aperture
taped over – inside the glass. Which is odd, since this one has a light sensor –
a photodiode – for turning the laser off in daylight. Except the sensor will never see daylight
with tape in front of it… Digging deeper, I immediately spot the
problem with the motion function. There’s no diffraction grating on the spinning cylinder. The grating has come loose. Unlike the other one,
they only glued this one. And not very well. At least it is an easy fix for later. All right, time to open the last one. It is bigger and more solidly build,
but has the same elements as the other ones. Gives me a chance to rest my
winter-sore throat – cue the music. And now, thanks to the help from my patrons We will test the lasers power
output on a laser power meter. First on the collimated laser beams, which is
easy on the one missing a diffraction grating. However the light sensor is a good
safety feature when the laser is opened. It will not turn on until I tape over the sensor. I will start with the red laser.
Let’s see if it’s under 1 milliwatt. No. 28 milliwatts (mW) on the red alone. How about the green laser? 24 mW. Seems high to me for a Class 2 labeled laser But on the other hand – this is
with the laser disassembled. I will measure the output at the aperture –
after I have fixed the motion function. It is no longer one collimated beam
after the diffraction gratings. But with 26 mW
I can’t help but think that up close an eye would collect
and focus way more than 1 mW. Do not stare into these lasers at close range! Here are the measurements for the other lasers. Ready to see the power from the brightest one? They surely did use stronger lasers in this one. 80 mW green is enough for a visible beam. As with many laser pointers,
the conclusion is once again: Do not judge a laser by its label. Always expect lasers to be a risk for the eyes. Thanks to all my patrons. Creators like me aren’t always
praised here on the internet. But at least I have your fantastic support. Thank you very much! Thanks for watching.
Bye for now.

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