laser

517 Articles

Pi-Based Spectrometer Puts The Complexity In The Software

April 23, 2021 by 43 Comments

Play around with optics long enough and sooner or later you’re probably going to want a spectrometer. Optical instruments are famously expensive, though, at least for high-quality units. But a useful spectrometer, like this DIY Raspberry Pi-based instrument, doesn’t necessarily have to break the bank.

This one comes to us by way of [Les Wright], whose homebrew laser builds we’ve been admiring for a while now. [Les] managed to keep the costs to a minimum here by keeping the optics super simple. The front end of the instrument is just a handheld diffraction-grating spectroscope, of the kind used in physics classrooms to demonstrate the spectral characteristics of different light sources. Turning it from a spectroscope to a spectrometer required a Raspberry Pi and a camera; mounted to a lens and positioned to see the spectrum created by the diffraction grating, the camera sends data to the Pi, where a Python program does the business of converting the spectrum to data. [Les]’s software is simple by complete, giving a graphical representation of the spectral data it sees. The video below shows the build process and what’s involved in calibrating the spectrometer, plus some of the more interesting spectra one can easily explore.

We appreciate the simplicity and the utility of this design, as well as its adaptability. Rather than using machined aluminum, the spectroscope holder and Pi cam bracket could easily be 3D-printer, and we could also see how the software could be adapted to use a PC and webcam.

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Hacking An Air Assist For The Ortur Laser

April 21, 2021 by 13 Comments

Getting great results from a laser cutter takes a bit of effort to make sure all of the settings are just right. But even then, if the air between the material and the laser source is full of smoke and debris it will interfere with the laser beam and throw off the results. The solution is to add air assist which continuously clears that area.

Earlier this year I bought an Ortur laser engraver/cutter and have been hacking on it to improve the stock capabilities. last month I talked about putting a board under the machine and making the laser move up and down easily. But I still didn’t have an air assist. Since then I found a great way to add it that will work for many laser cutter setups.

I didn’t design any of these modifications, but I did alter them to fit my particular circumstances. You can find my very simple modifications to other designs on Thingiverse. You’ll also find links to the original designs and you’ll need them for extra parts and instructions, too. It is great to be able to start with work from talented people and build on each other’s ideas.

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Scratch-Built CO2 Laser Tube Kicks Off A Laser Cutter Build

March 31, 2021 by 30 Comments

When we see a CO2 laser cutter build around these parts, chances are pretty good that the focus will be on the mechatronics end, and that the actual laser will be purchased. So when we see a laser cutter project that starts with scratch-building the laser tube, we take notice.

[Cranktown City]’s build style is refreshingly informal, but there’s a lot going on with this build that’s worth looking at — although it’s perhaps best to ignore the sourcing of glass tubing by cutting the ends off of an old fluorescent tube; there’s no mention of what became of the mercury vapor or liquid therein, but we’ll just assume it was disposed of safely. We’ll further assume that stealing nitrogen for the lasing gas mix from car tires was just prank, but we did like the rough-and-ready volumetric method for estimating the gas mix.

The video below shows the whole process of building and testing the tube. Initial tests were disappointing, but with a lot of tweaking and the addition of a much bigger neon sign transformer to power the tube, the familiar bluish-purple plasma made an appearance. Further fiddling with the mirrors revealed the least little bit of laser output — nowhere near enough to start cutting, but certainly on the path to the ultimate goal of building a laser cutter.

We appreciate [Cranktown City]’s unique approach to his builds; you may recall his abuse-powered drill bit index that we recently covered. We’re interested to see where this laser build goes, and we’ll be sure to keep you posted.

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How Laser Headlights Work

March 22, 2021 by 142 Comments

When we think about the onward march of automotive technology, headlights aren’t usually the first thing that come to mind. Engines, fuel efficiency, and the switch to electric power are all more front of mind. However, that doesn’t mean there aren’t thousands of engineers around the world working to improve the state of the art in automotive lighting day in, day out.

Sealed beam headlights gave way to more modern designs once regulations loosened up, while bulbs moved from simple halogens to xenon HIDs and, more recently, LEDs. Now, a new technology is on the scene, with lasers!

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The Devil Is In The Details For This Open Air Laser

March 17, 2021 by 23 Comments

Normally, we think of lasers as pretty complex and fairly intimidating devices: big glass tubes filled with gas, carefully aligned mirrors, cooling water to keep the whole thing from melting itself, that sort of thing. Let’s not even get started on the black magic happening inside of a solid state laser. But as [Jay Bowles] shows in his latest Plasma Channel video, building a laser from scratch isn’t actually as difficult as you might think. Though it’s certainly not easy, either.

The transversely excited atmospheric (TEA) laser in question uses high voltage passed across a a pair of parallel electrodes to excite the nitrogen in the air at standard atmospheric pressure, so there’s no need for a tube and you don’t have to pull a vacuum. The setup shakes so many UV photons out of the nitrogen that it doesn’t even need any mirrors. In fact, you should be able to get almost all the parts for a TEA laser from the hardware store. For example, the hexagonal electrodes [Jay] ends up using are actually 8 mm hex keys with the ends cut off.

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Laser Focus Made Easier With IR Filter

March 9, 2021 by 13 Comments

If you’ve used a diode laser engraver or cutter, you know that focus is critical. You’d think it would be relatively simple to get a sharp focus, but it isn’t that simple. [Makers Mashup] shows in a video how to use an adjustable IR filter to cut out all the light bleed to get a sharp image to make focusing simpler.

The filter he shows adjusts from 530nm to 750nm and is made to screw into a 72mm lens, but it works fine with your eyeballs, too. [Makers Mashup] says he’ll eventually make a stand for it so he can look through it with both hands free.

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Laser Zap That Mosquito

March 8, 2021 by 98 Comments

When we first heard of [Ildar Rakhmatulin’s] plan to use OpenCV on a Raspberry Pi to detect mosquitos and then zap them with a 1 watt laser, we thought it was sort of humorous. However, the paper points out that 700,000 people die each year from mosquito bites — we didn’t verify that, but according to the article that’s twice the number of people murdered each year. So the little pests are pretty effective assassins.

It looks as though the machine has been built, at least in a test configuration. A galvanometer aims the death ray using mirrors, and with the low power and lossy mirrors the mosquitos can only be a small distance from the machine — about a foot.

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