DIY Lasers Hack Chat

October 5, 2020 by Dan Maloney 10 Comments

Join us on Wednesday, October 7th at noon Pacific for the DIY Lasers Hack Chat with Les Wright!

It’s not too much of a reach to say that how we first experienced the magic of lasers sort of dates where we fall on the technology spectrum. For the youngest among us, lasers might have been something trivial, to be purchased for a couple of bucks at the convenience store. Move back a few decades and you might have had to harvest a laser from a CD player to do some experiments, or back further, perhaps you first saw a laser in high school physics class, with that warm, red-orange glow of a helium-neon tube.

But back things up only a few decades before that, and if you wanted to play with lasers, you had to build one yourself. It was a popular if niche hobby with a dedicated following of amateur physicists who scrounged around for the unlikely parts needed: ruby rods, quartz-glass tubes, and exotic dyes. Couple them together with high-voltage power supplies, vacuum pumps made from converted refrigerator compressors, and homemade optical benches, and if the stars aligned, these parts could be coaxed into producing a gloriously intense burst of light, which as often as not hooked its creator as a lifelong laser addict.

We’re not sure which camp Les Wright falls into, but from the content of his growing YouTube channel, we’d say he’s caught the laser bug. We recently took a look at his high-performance nitrogen laser, which he’s been having fun with as the basis for a tunable dye laser. Along the way he’s been necessarily mucking around with high-voltage power supplies, oscilloscopes, and the occasional robot or two.

Les will stop by the Hack Chat to talk about everything going on in his lab, with a focus on his laser experiments. Join us with your questions on DIY lasers, and stop by to pick up some tricks that might help you catch the laser bug too.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 4 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Hackaday Links: September 27, 2020

September 27, 2020 by Dan Maloney 15 Comments

Hardly a week goes by without a headline screaming about some asteroid or another making a close approach to Earth; it’s only by reading the fine print that we remember what an astronomer’s definition of “close” means. Still, 2020 being what it is, it pays to stay on top of these things, and when you do the story can get really interesting. Take asteroid 2020 SO, a tiny near-Earth asteroid that was discovered just last week. In a couple of weeks, 2020 SO will be temporarily captured into Earth orbit and come with 50,000 km near the beginning of December. That’s cool and all, but what’s really interesting about this asteroid is that it may not be a rock at all. NASA scientists have reverse-engineered the complex orbit of the object and found that it was in the vicinity of Earth in late 1966. They think it may be a Centaur booster from the Surveyor 2 moon mission, launched in September 1966 in the runup to Apollo. The object will be close enough for spectral analysis of its. surface; if it’s the booster, the titanium dioxide in the white paint should show up loud and clear.

Lasers are sort of forbidden fruit for geeks — you know you can put an eye out with them, and still, when you get your hands on even a low-power laser pointer, it’s hard to resist the urge to shine it where you shouldn’t. That includes into the night sky, which as cool as it looks could be bad news for pilots, and then for you. Luckily, friend of Hackaday Seb Lee-Delisle has figured out a way for you to blast lasers into the night sky to your heart’s content. The project is called Laser Light City and takes place in Seb’s home base of Brighton int he UK on October 1. The interactive installation will have three tall buildings with three powerful lasers mounted on each; a smartphone app will let participants control the direction, shape, and color of each beam. It sounds like a load of fun, so check it out if you’re in the area.

We got an interesting story from a JR Nelis about a quick hack he came up with to help his wife stay connected. The whole post is worth a read, but the short version of the story is that his wife has dementia and is in assisted living. Her landline phone is her social lifeline, but she can’t be trusted with it, lest she makes inappropriate calls. His solution was to modify her favorite cordless phone by modifying the keypad, turning it into a receive-only phone. It’s a sad but touching story, and it may prove useful to others with loved ones in similar situations.

We pay a lot of attention to the history of the early computer scene, but we tend to concentrate on computers that were popular in North America and the UK. But the Anglo-American computers were far from the only game in town, and there’s a new effort afoot to celebrate one of the less well-known but still important pioneer computers: the Galaksija. Aside from having a cool name, the Yugoslavian Z80 computer has a great story that will be told in documentary form, as part of the crowdsourced Galaksija project. The documentary stars our own Voja Antonic, who was key to the computer’s development. In addition to the film, the project seeks to produce a replica of the Galaksija in kit form. Check out the Crowd Supply page and see if it’s something you’re willing to back.

There’s an interesting new podcast out there: the Pick, Place, Podcast. Hosted by Chris Denney and Melissa Hough, it comes out every other week and is dedicated to the electronic assembly industry. They’ve currently got eight episodes in the can ranging from pick and place assembly to parts purchasing to solder paste printing. If you want to learn a little more about PCB assembly, this could be a real asset. Of course don’t forget to make time for our own Hackaday Podcast, where editors Mike and Elliot get together to discuss the week in hardware hacking.

Wooden Disc Player Translates Binary Back Into Text

September 18, 2020 by Kristina Panos 10 Comments

[jbumstead] used MATLAB to convert the text messages into binary to be cut out of the disk.

[jbumstead] wanted to demonstrate the idea of information-storing devices such as LPs, CDs, and old hard drives. What he came up with lies directly at the intersection of art and technology: an intricately-built machine that plays beautiful collaged wooden disks. Much like the media that inspired the Wooden Disk Player, it uses a laser to read encoded data, which in this case is short bits of text like “Don’t Panic”.

These snippets are stored in binary and read by a laser and photodiode pair that looks for holes and not-holes in the disk. The message is then sent to an Arduino Nano, which translates it into English and scrolls the text on an LED matrix. For extra fun, the Nano plays a MIDI note every time it reads a 1, and you can see the laser reading the disk through a protective acrylic shield.

Though the end result is fantastic, [jbumstead] had plenty of issues along the way which are explored in the build video after the break. We love it when people show us their mistakes, because it happens to all of us and we shouldn’t ever let it tell us to stop hacking.

If anyone knows their way around lasers, it’s [jbumstead]. We loved playing their laser harp at Supercon!

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The Astronomical Grit Of Ronald McNair

September 3, 2020 by Kristina Panos 23 Comments

There is more than one way to lead a successful life. Some people have all the opportunity in the world laid out before them, and it never does them any good. Others have little more than the determination and desire they’ve dredged up within themselves, and that grit turns out to be the abrasive that smooths the path ahead.

Ronald McNair succeeded despite poverty, racism, and an education system designed to keep Black people down. He became an accidental revolutionary at the age of nine, when he broke the color barrier in his small South Carolina town via the public library. This act of defiance in pursuit of education would set the course for his relatively short but full life, which culminated in his career as a Space Shuttle mission specialist.

Rule-Breaker with a Slide Rule

Ronald McNair was born October 21, 1950 in Lake City, South Carolina, the second of three sons, to Pearl and Carl McNair. His mother was a teacher, and encouraged his love of reading. Ronald’s father, Carl was an auto mechanic who never finished high school and always regretted it. Though the family was poor, Ron grew up surrounded by books, music, and support.

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How About A Nice Cuppa TEA Laser?

August 9, 2020 by Dan Maloney 11 Comments

If lasers are your hobby, you face a conundrum. There are so many off-the-shelf lasers that use so many different ways of amplifying and stimulating light that the whole thing can be downright — unstimulating. Keeping things fresh therefore requires rolling your own lasers, and these DIY nitrogen TEA and dye lasers seem like a fun way to go.

These devices are the work of [Les Wright], who takes us on a somewhat lengthy but really informative tour of transversely excited atmospheric (TEA) lasers. The idea with TEA lasers is that a gas, often carbon dioxide in commercial lasers but either air or pure nitrogen in this case, is excited by a high-voltage discharge across long parallel electrodes. TEA lasers are dead easy to make — we’ve covered them a few times — but as [Les] points out, that ease of construction leads to designs that are more ad hoc than engineered.

In the video below, [Les] presents three designs that are far more robust than the typical TEA laser. His lasers use capacitors made from aluminum foil with polyethylene sheets for dielectric, sometimes with the addition of beautiful “doorknob” ceramic caps too. A spark gap serves as a very fast switch to discharge high voltage across the laser channel, formed by two closely spaced aluminum hex bars. Both the spark gap and the laser channel can be filled with low-pressure nitrogen. [Les] demonstrates the power and the speed of his lasers, which can even excite laser emissions in a plain cuvette of rhodamine dye — no mirrors needed! Although eye protection is, of course.

These TEA lasers honestly look like a ton of fun to build and play with. You might not be laser welding or levitating stuff with them, but that’s hardly the point.

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Laser Cutting Your Way To An RGB LED Table

July 24, 2020 by Tom Nardi 19 Comments

You’ve got the RGB keyboard, maybe even the RGB mouse. But can you really call yourself master of the technicolor LED if you don’t have an RGB table to game on? We think you already know the answer. Luckily, as [ItKindaWorks] shows in his latest project, it’s easy to build your own. Assuming you’ve got a big enough laser cutter anyway…

The construction of the table is quite straightforward. Using an 80 watt laser cutter, he puts a channel into a sheet of MDF to accept RGB LED strips, a pocket to hold a Qi wireless charger, and a hole to run all the wires out through. This is then backed with a second, solid, sheet of MDF.

Next, a piece of thin wood veneer goes into the laser cutter. In the video after the break you can see its natural tendency to roll up gave [ItKindaWorks] a little bit of trouble, but when strategically weighted down, it eventually lays out flat. He then uses the laser to blast an array of tiny holes in the veneer, through which the light from the LEDs will shine when it’s been glued over the MDF. A few strips of plastic laid over the strips serve both to diffuse the light and support the top surface.

The end result is truly gorgeous and has a very futuristic feel. Assuming you’ve got the equipment, it’s also a relatively simple concept to experiment with. It’s yet another example of the unique construction techniques possible when you add a high-powered laser to your arsenal.

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500 Lasers Are Not Necessarily Better Than One, But They Look Great

July 13, 2020 by Dan Maloney 29 Comments

If playing with but a single laser pointer is fun, then playing with 500 laser pointers must be 500 times the fun, right? So by extension, training 500 laser pointers on a single point must be the pinnacle of pointless mirth. And indeed it is.

When we first spotted this project, we thought for sure it was yet another case of lockdown-induced boredom producing an over-the-top build. Mind you, we have no problem with that, but in this case, [nanoslavic] relates that this is actually a project from a few years back. It’s really as simple as it looks: 500 laser pointer modules arranged on a plate with a grid of holes in a 25 by 20 array. As he placed the laser modules on the board with a glob of hot glue, he carefully aimed each one to hit a single point about a meter and a half away. There are also a handful of blue LEDs nestled into the array, because what project is complete without blue LEDs?

The modules are wired in concentric circuits and controlled by a simple bank of toggle switches. Alas, 500 converging ~~150-mW~~ 5 mW lasers do not a ~~75-W~~ 2.5 W laser make; when fully powered, the effect at the focal point is reported to be only a bit warm. But it looks incredible, especially through smoke. Throwing mirrors and lenses into the beam results in some interesting patterns, too.

You’ll still need to take safety seriously if you build something like this, of course, but this one is really just for show. If you’re really serious about doing some damage with lasers, check out the long list of inadvisable laser builds that [Styropyro] has accumulated — from a high-powered “lightsaber” to a 200-Watt laser bazooka.

(Terminate your beams carefully, folks. We don’t want anyone going blind.)

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