Hey Habr. In this article, I will talk about my recent creation, created from 500 laser modules, like cheap low-power laser pointers. There are a lot of clickable pictures under the cut.
Attention! Even low-power laser emitters under certain conditions can cause harm to health or damage photographic equipment. Do not try to repeat the experiments described in the article.
Note. On where you can see more. However, the article describes the creation process in more detail and here the picture is better (especially when clicked).
Laser modules
I'll start with a description of the laser modules themselves. There are a lot of different options for sale now, differing in wavelength, power and shape of the output radiation, the design of the optical system and mounting, as well as build quality and price.
I chose the cheapest modules sold in China in batches of 100 pieces worth about 1000 rubles per batch. According to the description of the seller, they give out 50 mW at a wavelength of 650 nm. As for 50 mW, I doubt it, most likely there is not even 5 mW. I bought several similar modules in Russia at a price of 30 rubles apiece. In online stores, they are found under the name LM6R-dot-5V. They shine like red laser pointers, sold in different variations in any stall with knick-knacks.
Structurally, this module looks like a metal cylinder with a diameter of 6 mm and a length of 14 mm (together with the board). The body material is most likely steel, as it has good magnetic properties. The housing is connected to the positive contact.
Inside the case is a plastic lens and a laser chip mounted on a small printed circuit board. There is also a resistor on the board, the value of which depends on the declared supply voltage. I used 5V modules with a 91 ohm resistor. With an input voltage of 5V on the module, the voltage on the laser chip is 2.4V, while the current is 28 mA. The design is completely open from the side of the board, so that any dust or moisture can easily get inside. Therefore, I sealed the back of each module with hot glue. In addition, the chip and lens are not positioned accurately, so the output may not be parallel to the housing axis. During operation, the module heats up to a temperature of 35-40Β°C.
original version
Initially (it was a year ago) I bought 200 laser modules and decided to direct them to one point using a purely geometric method, that is, without adjusting each module individually, but by installing each emitter in special cutouts. To do this, I ordered special fasteners made of plywood 4 mm thick.
The laser modules were pressed against the cutout and glued with hot glue. The result was a setup that produced a beam of 200 laser dots with a diameter of about 100 mm. Although the result was far from hitting a single point, many were impressed by this idea (I posted a video on youtube) and it was decided to continue the topic.
I dismantled a system of 200 laser modules and made a laser garland out of them. It turned out interesting, but not convenient, since under the weight of the body all the rays were directed downward. But by this time I bought a smoke machine and for the first time I saw how cool these lasers look in the fog. I decided to repeat the original idea, but manually direct each laser to one point.
laser light
For the new version, I ordered another 300 laser modules. As a fastener, I made a square plate with a side of 440 mm from plywood 6 mm thick with a matrix of holes of 25 rows and 20 columns. Hole diameter 5 mm. Later I painted it silver. To mount the plate, I used a stand from an old LCD monitor.
I fixed the plate in a vise, and at a distance of 1350 mm (the length of my table) I hung a paper target measuring 30x30 mm, into the center of which I directed each laser beam.
The process of pasting the laser module was as follows. I inserted the wires of the module into the hole and connected the crocodiles with the supply voltage to them. Next, I filled the module case and the hole in the plate with hot glue. Under the plate lay a fan for accelerated cooling of the glue. Since the glue hardens slowly, I could easily adjust the position of the module, focusing on the position of the laser dot on the target. On average, it took me 3.5 minutes for one laser module.
It is convenient to use hot melt glue, as it can be heated and the module corrected. However, there are two downsides. First, the heating of the modules led to deformation of the module structure, which was expressed in the expansion of the laser beam. Some modules lost their brightness dramatically from heating and had to be replaced. Secondly, after cooling, the hot melt adhesive continued to deform for several hours and slightly divert the laser beam in an arbitrary direction. The last factor forced to change the original name of the project "500 laser pointers at one point."
Since the work was carried out only occasionally in the evenings and on weekends, it took about three months to glue all 500 laser modules. Taking into account the delivery of modules and the plate, there will be six months.
For a special effect, I added blue LEDs to the laser modules.
Providing power to all modules is not an easy task, because you need to connect 1000 contacts and evenly distribute the current. I connected all 500 positive contacts into one circuit. I divided negative contacts into 10 groups. Each group has its own toggle switch. In the future, I'm going to add 10 microcontroller-controlled electronic keys to music to enable groups.
To power all the modules, I purchased a constant voltage source , which produces a voltage of 5V with a current of up to 60A. It has a small size and a convenient terminal block for connecting the load.
The final circuit with all laser modules turned on has a consumption of about 14 amperes. The figure below shows the location of all laser dots on the target. As you can see, I almost fit into βone placeβ with a size of 30x30 mm. One spot outside the target appeared due to one module having spurious side radiation.
The resulting device does not look very pretty, but all its beauty is shown in the darkness and fog.
I tried to touch the intersection of the rays. Warmth is felt, but not strong.
And he even pointed the camera directly at the emitters (I myself use green goggles).
It was very interesting to use mirrors and lenses.
Later, I added the ability to modulate laser modules with an audio signal and got a kind of musical laser installation. You can look at her .
This project is purely for leisure and I was pleased with its results. At the moment, I do not set myself the same time-consuming tasks, but in the future I will probably come up with something else. I hope you were interested too.
Thank you for attention!
Source: habr.com