Hi, guys, welcome to electrical projects, today I’ll show you how to build a simple
spectrum analyzer that can analyze light, including Infrared and ultraviolet light.
The two key components of this device are a web camera and empty DVD disk.
But also, well need some kind of housing for the analyzer.
The material of the housing should be not transparent, and of course, it will be better
if the material is black.
I am going to use wooden planks painted black.
But before building the analyzer, I am going to remove the infrared filter from this webcamera.
It is not necessary to remove the filter, but if you remove the filter you will
be able to analyze infrared light also, and I really want to make this analyzer as useful
as I can, so I am going to remove the filter.
This piece of glass on top is the infrared filter, so let’s remove it.
Now the camera is ready to see infrared, so, let’s assemble it.
Now let’s build the housing…
The main idea here is to build a box with a slit for the light on the one side.
So let’s do it.
Now when the box is half completed let’s install the camera.
I am using a screw to fix the camera to the housing.
Remember, the camera should be installed on the 30-degree angle.
Now when the camera installed, we can glue a piece of DVD disc to the lens.
Let’s unscrew the lens and prepare DVD disk.
But first let me explain why do we need DVD disk at all, well DVD disk will work like
a diffraction gratings, in other words, it splits light into a rainbow, and the web camera
will see the rainbow, and software will analyze it.
Well, enough talk; let’s break the disk already,
nice!
This piece of DVD disk looks good enough, so let’s glue it with using some hot melt adhesive
Now’ let’s install this lens, with a piece of DVD disk, and this device is almost ready.
Now after adding additional wooden planks and beaming light through the slit you should
see a horizontal line on the spectrum analyzer software, if it is not the horizontal line,
you need to rotate the lens and make the line horizontal.
Adjusting is very individual, just experiment.
Here is how my completed analyzer looks like.
Now we need to calibrate this analyzer, I will use a fluorescent lamp.
With this cardboard box, I regulate the amount of light that spectrum analyzer gets through the slit.
And here is the light source; it is just a regular fluorescent lamp.
Let’s have look at the spectrum.
As you can see the fluorescent lamp produces not continues spectrum
and the spectrum has a lot of peaks.
Not all these peaks are stable, but these two peaks are stable and they don’t move,
they are 436 and 546 nm So let's use them for the calibration.
To do the calibration you need to click tools, trim points,
choose “fluorescent 436 and 546 nm”
Now we need to align these two peaks to 436 and 546 nm respectively.
Now click on "trim scale" and after that, the calibration is finished.
Now I’ll show you how different light sources look like on the spectrum.
We already saw the spectrum of a regular fluorescent lamp, but now let’s try something more interesting.
This is a Wood's lamp, sometimes also called black light; it produces ultraviolet light,
let’s have look at the spectrum.
As you can see it produces a little bit of blue, some violet,
and also it produces ultraviolet light that is not visible for our eyes.
Now let’s test a regular incandescent light bulb, and I’ll show why this bulb is not energy efficient.
Just have a look how much energy is wasted on the infrared light, we cannot see infrared,
but most of light is infrared light.
So, basically, this light bulb mostly produces heat instead of visible light, and maybe it
is ok in winter, but it is definitely not good in summer.
Now let me show you spectrum of these white LEDs, the light from LEDs much better than
light from florescent lamp, because there is no such high peaks, the spectrum is more even.
And now I’ll show how RGB color mixing works.
To demonstrate that I’ll use RGB lighting that I have in my room.
First, let choose pink color, as you can see on the spectrum it is actually is not pink,
it is blue and red turned on together, moreover there is no pink color even on the
rainbow spectrum, which means it is not a real color at all, your brain just make this
color up when your eyes see blue and red.
And when I choose white color it is just red green and blue turned on 100 present.
Now let me show how automatic color mixing works.
And the last thing that I want to show is the spectrum of this remote control.
Of course, that is obvious that it is infrared remote control, but let’s have a look anyway.
As you can see it emits light 930nm
and as you can see it is beyond visible spectrum that human eyes can see.
To detect this light it is necessary to remove the infrared filter from the web camera.
And that is all for today, like this video if it was interesting, and thanks for watching!