👩‍👩‍👧‍👧 👊 👨🏾‍🔬 Laser "blaster" operating model 👩🏽‍🔬 ✌🏿 🤳🏻

As a child, I watched Star Wars and wanted to get myself some kind of fantastic device. A Jedi sword is only possible in the Star Wars galaxy with their specific physics. In our universe, a laser beam cannot fly a meter and then abruptly break off. Making a glow stick is not interesting. But the blaster ... To make it a firing intermittent beam also does not work. But to make a device that “shoots” a beautiful beam in the dark is quite possible.

Safety

The laser is hazardous to vision. Therefore, experiments with the laser and optics should be carried out with goggles. Even 100 ruble glasses from the workwear store delay glare, a reflected and unfocused beam. The focused beam will burn them of course. But in my device there is none. There are glasses of a higher class of protection. Their focused beam charms, but does not burn. This is for those who work with powerful cutting lasers.
Here's how the most ordinary glasses work:

Laser

And so, my task is to get a beautiful long beam, visible in the atmosphere in the dark or at dusk. In fact, you need a powerful laser pointer in the visible spectrum. Only in my device, it will not shine continuously, but will “shoot” with single pulses or bursts.
I decided that the most spectacular would be a blue or green glow. And then in the Chinese online store I came across a module for wood engraving with a wavelength of 450 nm.

Something like this:

I chose a module for 6 Chinese watts. The Chinese, of course, lied a little :) And in reality, this module consumes 9 watts and produces about 2 watts. This is good. The fact is that in a blue laser LED, the crystal is quite large and it emits from the end of the plate.

This is what it looks like:

That is, it gives out a wide strip of blue light. Here is the angular distribution of the light from the datasheet to the LED:

The strip will be something like this:

The closer the light source is to the point light, the easier it is to focus and get a thin beam. In the case of a blue laser LED, in any case we get a beam in the form of a strip due to the design of the crystal. The more powerful the laser LED, the more crystal it has, which means we will get just a wider strip. Conclusion: it’s not worth chasing power. It is necessary to choose an LED with the optimal ratio of power and crystal size. My module has a rather small LED and it fits.

Now optics

The laser LED produces a streak of light with an angle of about 40 degrees. And I need a thin long beam. So, we need collimator optics. A lens for wood engraving came with the module, and it focuses the beam to a point at a distance of 10-40 mm from the module. Of course, I pampered and burned the tree. But I need something completely different. In principle, if you focus the beam with this lens at a certain point and place this point in the focus of another longer telephoto lens, I get what I need, but the quality of this lens is disgusting. The lens is plastic, glued crookedly, defects and bubbles in the lens. For the first experiments, it was enough, but then I ordered a collimator lens with normal glass lenses.

Here is one:

The quality of this lens is much higher and the lenses in it are 3. It is used in laser pointers by itself and can produce a beam, but the beam divergence is quite large. My system will be better.

Optical design of my “blaster”:

The longer the telephoto lens is at the exit, the smaller the beam divergence will be. You can put a telescope, but it will be too much. My "blaster" should be compact like an Imperial attack aircraft and inexpensive. This is still a toy. I put a flat-convex lens with a focal length of 80mm and this gives a beam divergence of about 3.5 arc minutes. It is not bad and looks beautiful. At the exit, the beam thickness is 6 mm, at a distance of 11 m - 14 mm, and at a distance of 100 m the laser strip will be slightly more than 10 cm. After exiting the device, the beam has no focus points, which means that they can not set fire to anything. This is good in terms of security. Judging by the frames from the film, the diameter of the blaster beam is a few centimeters. At a distance of the "game" in 20-50m the way it will be in my case.

I mounted the optical components on a metal plate. The fastening must be reliable, moving components to a tenth of a millimeter will keep focus. A Weaver rail is mounted on the laser module for mounting an optical sight. In the film, he is even on a blaster - a pistol by Han Solo and on my blaster it simply must be!

Optical system without casing:

Beam at a distance of 11m. Wave effects are visible:

Housing

I decided that the product should be in the style and spirit of "Star Wars", but it is not necessary to copy the props from the film. The main thing is my functionality, not copying. Moreover, in the early films, even in the frame, it can be seen that the weapon is a props. I can do better and try to do it.

I concluded the following.

The weapon should be compact with the ability to shoot "from the hip." In the film, everyone does just that, scorching in all directions and they don’t fall into the “good guys”. Although all blasters have an optical sight or something like that :) So, the lineup should be bullpup. The weapon should be futuristic, but without unnecessary fake ruffles. This is not steam punk.
As a body, I took the butt from some domestic air.

Here is one:

The case is plastic, quite futuristic and consists of 2 halves. So, it will be easy to put electronics there.

Powered by 2x 18650. The voltage drop on the laser LED 4.3-4.5V, so that one element can not do.

On the case there is a fire mode switch, power and fire rate adjustment knobs, and a battery indicator.

Case with "filling":

Controller

I made a controller based on Arduino nano.

His tasks:

control laser power (PWM)
to form the "firing" impulses in single and bursts
monitor the temperature of the laser module and the battery charge
enable safe power mode

Here I will not dwell in detail, each (or almost every :) Khabrovsk resident will easily solder and write this.

Controller board:

Safe mode

In lasers, this is a necessary function.

At the shooting range, I saw some people shooting a FIRE WEAPON, after a misfire, trying to look into the barrel! I wonder what they wanted to see there? How will the “bird” fly out?

What can we say about the laser "toy". Onlookers “let me see” can easily spoil the sight of oneself or one's neighbors. In laser projectors, powerful laser pointers make a hard key lock. To turn on the device could only be a person who understands what he is doing, complies with TB and applies protective equipment. (This is ideal). I have it too. Without a “safety key”, the laser power is limited to units of milliwatts and it is safe for sight. At a long distance (more than 200-300m), the beam is also safe even at maximum power. Due to beam divergence and atmospheric absorption.

Ready Blaster

Everything is assembled and working!

How is it? In my opinion, very futuristic ...

Each element is functional, no fake.

Now let's look at the footage from the Star Wars films, where they are scorching from the blasters with might and main.
So that there was then something to compare.

KDPVN - by itself!

More from later films:

And from earlier:

Well, now, the battle for the Galaxy awaits us. Let's go out and shoot!

Just do not forget that in the case of a game of Star Wars, all Jedi, Sith and other heroes of resistance and henchmen of the Empire should wear safety glasses!

Fortunately, they cost much less even paintball masks ...

Test

Everything is really shot here, no computer graphics.
Only a blaster and a camera with a 70-200mm lens.
Photos are clickable.

Turn to the wall shutter speed a couple of seconds: Shot at the wall: At a tree: I shoot to the side: I almost hit the operator: The distance to me is about 50-60m. It is worth noting one feature. Shooting does not look like a flashlight or pointer. Of course, I understand that the speed of light is very high and it’s unrealistic to notice the beam’s propagation, but pulses lasting from milliseconds to tens of milliseconds deceive the perception and it seems that the beam really flies through the air! A shot at the sky: Stars are visible in the sky , Imperial cruisers are not visible :) To the moon: