Putting The Finishing Touches On A 60W Laser

December 11, 2020 by Tom Nardi 26 Comments

At this point if you’re even remotely interested in home laser cutters, you know about the K40. These imported machines are very impressive considering they only cost around $400 USD, but naturally, quite a few corners had to be cut to get the price down. If you’re looking for something with a bit more punch and much higher build quality, a new breed of 60 watt lasers have started popping up on the usual import sites for around $2,000 USD.

While these more expensive machines are certainly much higher quality than the K40, [Jeremy Cook] found there was still plenty of room for improvement. For example, the machine didn’t have any switch cut off the laser when somebody opens the lid. While we don’t doubt some readers will consider this more of a feature than a bug, it’s hard to believe that a tool that costs this much wouldn’t at least offer such a thing as an option.

[Jeremy] also decided to add his own ammeter so he could see how much power the laser is drawing. While not strictly required for day to day operation, it turns out that the controller in many of these machines has a tendency to push the laser tubes beyond their design limits on the higher power settings. With the spec sheet for your tube and a permanent in-line ammeter, you can verify you aren’t unwittingly shortening the life of your new cutter.

Even if you ignore the modifications [Jeremy] makes in his video, it’s still a very illuminating look at what it takes to get one of these lasers ready for operation. Not only do you have to get the thing out of its shipping crate safely, but you need to come up with some way to deal with the fumes produced and get the water cooling system hooked up. It’s a decent amount of work, but the end results certainly look impressive.

While the K40 is still probably the better bet for new players, it’s good to see that there are some viable upgrades for anyone who’s outgrown their entry level machine but isn’t in a position to spend the money on an Epilog.

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Shhh… Robot Vacuum Lidar Is Listening

November 27, 2020 by Inderpreet Singh 5 Comments

There are millions of IoT devices out there in the wild and though not conventional computers, they can be hacked by alternative methods. From firmware hacks to social engineering, there are tons of ways to break into these little devices. Now, four researchers at the National University of Singapore and one from the University of Maryland have published a new hack to allow audio capture using lidar reflective measurements.

The hack revolves around the fact that audio waves or mechanical waves in a room cause objects inside a room to vibrate slightly. When a lidar device impacts a beam off an object, the accuracy of the receiving system allows for measurement of the slight vibrations cause by the sound in the room. The experiment used human voice transmitted from a simple speaker as well as a sound bar and the surface for reflections were common household items such as a trash can, cardboard box, takeout container, and polypropylene bags. Robot vacuum cleaners will usually be facing such objects on a day to day basis.

The bigger issue is writing the filtering algorithm that is able to extract the relevant information and separate the noise, and this is where the bulk of the research paper is focused (PDF). Current developments in Deep Learning assist in making the hack easier to implement. Commercial lidar is designed for mapping, and therefore optimized for reflecting off of non-reflective surface. This is the opposite of what you want for laser microphone which usually targets a reflective surface like a window to pick up latent vibrations from sound inside of a room.

Deep Learning algorithms are employed to get around this shortfall, identifying speech as well as audio sequences despite the sensor itself being less than ideal, and the team reports achieving an accuracy of 90%. This lidar based spying is even possible when the robot in question is docked since the system can be configured to turn on specific sensors, but the exploit depends on the ability to alter the firmware, something the team accomplished using the Dustcloud exploit which was presented at DEF CON in 2018.

You don’t need to tear down your robot vacuum cleaner for this experiment since there are a lot of lidar-based rovers out there. We’ve even seen open source lidar sensors that are even better for experimental purposes.

Thanks for the tip [Qes]

Cleaner Laser Cutting With A 3D-Printed Nozzle

November 25, 2020 by Donald Papp 24 Comments

[Nervous System] does a lot of laser cutting, and [Jesse] shared a fascinating experimental improvement to their laser cutter that consists of a 3D-printed nozzle for cleaner cuts. You can see the results for yourself above, where the difference between the two cuts is striking.

[Jesse]’s modification doesn’t affect the laser beam itself; it is an improvement on the air assist, which is the name for a constant stream of air that blows away smoke and debris as the laser burns and vaporizes material. An efficient air assist is one of the keys to getting nice clean laser cuts, but [Jesse] points out that a good quality air assist isn’t just about how hard the air blows, it’s also about how smoothly it does so. A turbulent air assist can make scorch marks worse, not better.

3D-printed nozzle to promote laminar air flow on the left, stock nozzle on the right.

As an experiment to improve the quality of the air flowing out the laser nozzle, [Jesse] researched ways to avoid turbulence by creating laminar flow. Laminar flow is the quality of a liquid having layers flowing past one another with little or no mixing. One way to do this is to force liquid through individual, parallel channels as it progresses towards a sharply-defined exit nozzle. While [Jesse] found no reference designs of laminar flow nozzles for air assists, there were definitely resources on making laminar flow nozzles for water. It turns out that interest in such a nozzle exists mainly as a means of modifying Lonnie Johnson’s brilliant invention, the Super Soaker.

Working from such a design, [Jesse] created a custom nozzle to help promote laminar flow. Sadly, a laser cutter head carries design constraints that make some compromises unavoidable; one is limited space, and another is the need to keep the laser’s path unobstructed. Still, after 3D printing it in rigid heat-resistant resin, [Jesse] found a dramatic improvement in the feel of the air exiting the nozzle. Some test cuts confirmed a difference in performance, which results in a noticeably cleaner kerf without scorching around the edges.

One of the things [Nervous System] does is make their own custom puzzles, so any improvement to laser cutting helps reliability and quality. When production is involved, just about everything matters; a lesson [Nervous System] shared when they discussed making the best plywood for creating their puzzles.

The Jolly Cart-Pushing Robot

September 14, 2020 by Orlando Hoilett 4 Comments

[Lance] loves making simple robots with his laser cutter. He finds great satisfaction from watching his robots operate using fairly simple mechanisms and designs a whole slew of them inspired by different animals, including a dinosaur and a dragon. His latest build is a jolly cart-pushing robot.

He cut each piece of his robot on his laser cutter, and in order to get the pieces to fit snugly together he made each tab a little bigger than its corresponding slot, ensuring the piece wouldn’t fall out. This also helps account for the loss in the material due to kerf, which is the bit of each piece of material that gets lost in the cut end of the laser cutter.

Making his robot walk was mostly as easy as attaching each leg to a simple DC motor such that the motor would rotate each leg in succession, pushing the robot along. From time to time, [Lance] also had to grease the robot’s moving parts using a bit of wax to help reduce friction. He even used a little rubber band to give the robot some traction.

[Lance] did a pretty good job detailing the build in his video. He also linked to a few other fun little robot designs that could entertain you as well. Pretty easy hack, but we thought you might find the results as satisfying as we did.

Robot companions may be here to stay. Time will tell.

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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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