Science Shows Green Lasers Might Be More Than You Bargained For

August 31, 2018 by 54 Comments

This may come as a shock, but some of those hot screaming deals on China-sourced gadgets and goodies are not all they appear. After you plunk down your pittance and wait a few weeks for the package to arrive, you just might find that you didn’t get exactly what you thought you ordered. Or worse, you may get a product with unwanted bugs features, like some green lasers that also emit strongly in the infrared wavelengths.

Sure, getting a free death ray in addition to your green laser sounds like a bargain, but as [Brainiac75] points out, it actually represents a dangerous situation. He knows whereof he speaks, having done a thorough exploration of a wide range of cheap (and not so cheap) lasers in the video below. He explains that the paradox of an ostensibly monochromatic source emitting two distinct wavelengths comes from the IR laser at the heart of the diode-pumped solid state (DPSS) laser inside the pointer. The process is only about 48% efficient, meaning that IR leaks out along with the green light. The better quality DPSS laser pointers include a quality IR filter to remove it; cheaper ones often fail to include this essential safety feature. What wavelengths you’re working with are critical to protecting your eyes; indeed, the first viewer comment in the video is from someone who seared his retina with a cheap green laser while wearing goggles only meant to block the higher frequency light.

It’s a sobering lesson, but an apt one given the ubiquity of green lasers these days. Be safe out there; educate yourself on how lasers work and take a look at our guide to laser safety. Continue reading “Science Shows Green Lasers Might Be More Than You Bargained For” →

Laser Draws Weather Report

June 23, 2018 by 13 Comments

Have you ever wished that a laser could tell you the weather? If you have, then [tuckershannon] has you covered. He’s created a machine that uses a laser and some UV sensitive paper to draw the temperature and a weather icon! And that’s not all! It’s connected to the internet, so it can also show the time and print out messages.

Building on [tuckershannon]’s previous work with glow-in-the-dark drawing, the brains inside this machine is a Raspberry Pi Zero. The laser itself is a 5mw, 405nm laser pointer with the button zip-tied down. Two 28BYJ-48 stepper motors are used to orient the laser, one for the rotation and another for the height angle. Each stepper motor is connected to a motor driver board and then wired directly to the Pi.

The base and arm that holds the laser were designed in SolidWorks and then 3d printed. The stepper motors are mounted perpendicular to one another and then the laser pointer mounted at the end. The batteries have been removed from the laser and the terminals are also wired directly to the raspberry pi. The Pi is then connected to Alexa via IFTTT so that it can be controlled by voice from anywhere.

The real beauty of [tucker]’s laser drawing machine is that is will draw out the temperature and weather icon, as well as drawing the time in either digital or analog forms! We’ve seen [tuckershannon]’s work before. The precursors to this project were his clock which uses a robotic arm with a UV LED on it to draw the time and another clock which uses similar robotic arm only with a laser attached. Let’s hope we get to see the rest of [tucker]’s progress!

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Robert Hall And The Solid-State Laser

May 22, 2018 by 14 Comments

The debt we all owe must be paid someday, and for inventor Robert N. Hall, that debt came due in 2016 at the ripe age of 96. Robert Hall’s passing went all but unnoticed by everyone but his family and a few close colleagues at General Electric’s Schenectady, New York research lab, where Hall spent his remarkable career.

That someone who lives for 96% of a century would outlive most of the people he had ever known is not surprising, but what’s more surprising is that more notice of his life and legacy wasn’t taken. Without his efforts, so many of the tools of modern life that we take for granted would not have come to pass, or would have been delayed. His main contribution started with a simple but seemingly outrageous idea — making a solid-state laser. But he ended up making so many more contributions that it’s worth a look at what he accomplished over his long career.

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The Internet Of Three-Pointers

March 30, 2018 by 1 Comment

When tossing something into the rubbish bin, do you ever concoct that momentary mental scenario where you’re on a basketball court charging the net — the game’s final seconds ticking down on the clock — making a desperate stretch and flicking some crumpled paper perfectly into the basket only for no one to notice your awesome skills? Well, now you can show off how good you are at throwing out garbage.

Well, not strictly garbage. The genesis of this IoT basketball hoop was in fact an inflatable ball on [Brandon Rice]’s desk that he felt would be more fun to fidget with if he could keep score. The hoop and backboard were laser cut on his Epilog cutter, and sport a Particle Photon to track and upload his running point tally to the Internet. An Arduino and IR sensor detect objects passing through the hoop — ultrasound proved to be too slow to keep up with [Rice]’s shots.

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Lasers, Mirrors, And Sensors Combine In An Optical Bench Game

March 24, 2018 by 11 Comments

Who would have thought you could make a game out of an optical bench? [Chris Mitchell] did, and while we were skeptical at first, his laser Light Bender game has some potential. Just watch your eyes.

The premise is simple: direct the beam of a colored laser to the correct target before time runs out. [Chris] used laser-cut acrylic for his playfield, which has nine square cutouts arranged in a grid. Red, green, and blue laser pointers line the bottom of the grid, with photosensors and RGB LEDs lining the grid on the other three sides. Play starts with a random LED lighting up in one of the three colors, acting as a target. The corresponding color laser comes on, and the player has to insert mirrors or pass-through blocks in the grid to create a path to the target. The faster you hit the CdS cell, the higher your score. It’s simple, but it looks really engaging. We can imagine all sorts of upgrades, like lighting up two different targets at once, or adding a beamsplitter block to hit two targets with the same color. Filters and polarizers could add to the optical fun too.

We like builds that are just for fun, especially when they’re well-crafted and have a slight air of danger. The balloon-busting killbots project we featured recently comes to mind.

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Teardown: What’s Inside A Christmas Laser Projector?

January 22, 2018 by 56 Comments

In the world of big-box retail, December 26th is a very special day. The Christmas music playing on the overhead speakers switches back to the family friendly Top 40, the store’s decorations get tossed in the compactor, and everything that’s even remotely related to the holiday is put on steep clearance. No more money to be made on the most commercialized of all holidays, so back to business as usual.

It’s in this narrow corridor of time, between the Great Holiday Unloading and the new spring products coming in, that you can find some fantastic deals on Christmas decorations. Not that long ago, this would hardly be exciting news for the readers of Hackaday. But Christmas lights and decorations have really started pushing the envelope in terms of technology: addressable RGB LED strands, Bluetooth controlled effects, and as of the last couple years, friggin’ lasers.

That’s right, you’ve seen them all over the neighborhood, probably took a few stray beams to the eye, you might even own your own. Laser projectors have been one of the most popular Christmas decorations for the last couple of years, and it’s not hard to see why. Just set the projector up in front of your house, and you’re done. No need to get on a ladder and string lights on the roof when you can just blast some directed energy up there instead.

Given how popular they are, I was surprised to see a lone Home Accents Holiday Multi-Color Light Projector on the clearance rack at Home Depot for around $14 a few days after Christmas. This was a 75% price reduction from normal MSRP, and right in that sweet impulse-buy price range. Let’s see what’s hiding inside!

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Laser Cutter Alignment Mod Skips Beam Combiner

December 11, 2017 by 27 Comments

A lot of the DIY laser engravers and cutters we cover here on Hackaday are made with laser diodes salvaged from Blu-ray drives and projectors, which are visible lasers in the 400 – 450nm range (appearing as violet or blue). Unfortunately there is an upper limit in terms of power on visible diode lasers, most builds max out at 5W or so. If you need more power than that, you’ll likely find yourself looking at gas laser cutters like the K40. While the K40 is a great starting point if you’re looking to get into “real” lasers, it’s a very different beast from the homebrew builds using visible lasers.

With a gas laser the beam itself is invisible, making it much more difficult to align or do test runs. One solution is to add a visible laser to the K40 which can be used to verify alignment, but making sure it’s traveling down the same path as the primary laser usually requires an expensive beam combiner. Looking to avoid this cost, [gafu] wanted to see if it was possible to simply move the visible laser into the path of the primary beam mechanically.

An adjustable microswitch detects when the lid has been opened.

In the setup that [gafu] has come up with, a cheap laser module (the type from a handheld laser pointer) is moved into the path of the primary laser on an arm that’s actuated by a simple hobby servo. To prevent the primary and visible lasers from firing at the same time, an Arduino is used to control the servo given the current state of the K40’s lid. If the lid of the K40 is open, the primary laser is shutoff and the visible laser is rotated into position so the operator can see where the primary laser’s beam would be hitting. Once the lid is closed, the visible laser rotates out of the way and the primary is powered back up.

Running the cutting or engraving job with the lid of the K40 machine open now let’s [gafu] watch a “dry run” of the entire operation with the visible laser before finally committing to blasting the target with the full power beam.

We’ve covered many hacks and modifications for everyone’s favorite entry-level CO2 laser cutter. From replacing the controller to making it bigger, K40 owners certainly seem like a creative bunch.