Laser Surgery: Expanding the Bed of a Cheap Chinese Laser Cutter

Don’t you just hate it when you spend less than $400 on a 40-watt laser cutter and it turns out to have a work area the size of a sheet of copy paper? [Kostas Filosofou] sure did, but rather than stick with that limited work envelope, he modified his cheap K40 laser cutter so it has almost five times the original space.

The K40 doesn’t make any pretenses — it’s a cheap laser cutter and engraver from China. But with new units going for $344 on eBay now, it’s almost a no-brainer. Even with its limitations, you’re still getting a 40-watt CO2 laser and decent motion control hardware to play with. [Kostas] began the embiggening by removing the high-voltage power supply from its original space-hogging home to the right of the work area. With that living in a new outboard enclosure, a new X-Y gantry of extruded aluminum rails and 3D-printed parts was built, and a better exhaust fan was installed. Custom mirror assemblies were turned, better fans were added to the radiator, and oh yeah — he added a Z-axis to the bed too.

We’re sure [Kostas] ran the tab up a little on this build, but when you’re spending so little to start with, it’s easy to get carried away. Speaking of which, if you feel the need for an even bigger cutter, an enormous 100-watt unit might be more your style.

Continue reading “Laser Surgery: Expanding the Bed of a Cheap Chinese Laser Cutter”

Little Laser Light Show is Cleverly Packaged, Cheap to Build

We’re suckers for any project that’s nicely packaged, but an added bonus is when most of the components can be sourced cheaply and locally. Such is the case for this little laser light show, housed in electrical boxes from the local home center and built with stuff you probably have in your junk bin.

When we first came across [replayreb]’s write-up and saw that he used hard drives in its construction, we assumed he used head galvanometers to drive the mirrors. As it turns out, he used that approach in an earlier project, but this time around, the hard drive only donated its platters for use as low mass, first surface mirrors. And rather than driving the mirrors with galvos, he chose plain old brushed DC motors. These have the significant advantage of being cheap and a perfect fit for 3/4″ EMT set-screw connectors, designed to connect thin-wall conduit, also known as electromechanical tubing, to electrical boxes and panels. The motors are mounted to the back and side of the box so their axes are 90° from each other, and the mirrors are constrained by small cable ties and set at 45°. The motors are driven directly by the left and right channels of a small audio amp, wiggling enough to create a decent light show from the laser module.

We especially like the fact that these boxes are cheap enough that you can build three with different color lasers. In that case, an obvious next step would be bandpass filters to split the signal into bass, midrange, and treble for that retro-modern light organ effect. Or maybe figuring out what audio signals you’d need to make this box into a laser sky display would be a good idea too.

Continue reading “Little Laser Light Show is Cleverly Packaged, Cheap to Build”

Robot Targets Eyeballs, Fires Lasers. OSHA’s Gonna Love this One

If you even think about hacking with lasers, you’re going to hear about eye safety. “Be careful” they’ll say. “Don’t look into laser with remaining eye” is a joke you’ll not be able to avoid. You’ll hear “Where are your goggles”, and about 1000 other warnings. Don’t get us wrong, laser/eye safety is important. However, the constant warnings can get a bit old — especially when you’re working with a “low power” class 3a laser — you know, the kind with a warning label that says “AVOID DIRECT EYE EXPOSURE” in big black letters on a yellow background.

[Michael Reeves] got fed up, and went a bit nuts. He built a robot specifically to shine a laser into human eyes. No, not a medical robot. This ‘bot lives in a pizza box, is built from servos, duct tape, and [Michael’s] tears. It just shoots lasers at people’s eyes. Needless to say, please, don’t try this at home, or at all.

Designing such a diabolical beast was actually rather simple. The software is written in C#. Frames are captured from an old Logitech webcam, then passed into Emgu CV, which is a .NET wrapper for OpenCV. [Michael] runs a simple face detection algorithm, and uses the results to aim a laser. The laser is mounted on two R/C style servos. An Arduino forms the glue between the servos and the PC.

[Michael] has a great deadpan delivery and it all makes for a great video. Think of him of a younger [Medhi] over at Electroboom.  But we can’t condone this behavior. Properly labeled and characterized red laser pointers have never been shown to cause eye damage. Yet if the laser is out-of-spec or reflects of something that further focuses the beam it is certainly capable of damaging eyesight.

We want [Michael’s] eyesight to remain intact so he can make more videos — he’s entertaining, even if ignoring safety warnings isn’t.

Continue reading “Robot Targets Eyeballs, Fires Lasers. OSHA’s Gonna Love this One”

Photochromic Eggs: Not for Breakfast

Photochromic paint is pretty nifty – under exposure to light of the right wavelength, it’ll change colour. This gives it all kinds of applications for temporary displays.  [Jiri Zemanek] decided to apply photochromic paint to an egg, utilising it to create stroboscopic patterns with the help of a laser.

Patterns for the egg are generated in MATLAB. A Discovery STM32 board acts as a controller, looking after the laser scanner and a stepper motor which rotates the egg. A phototransistor is used to sync the position of the laser and the egg as it rotates.

The photochromic paint used in this project is activated by UV light. To energize the paint, [Jiri] harvested a violet laser from a Blu-ray player, fitting it to a scanning assembly from a laser printer. Instead of scanning the laser across an imaging drum, it is instead scanned vertically on a rotating egg. Patterns can then be drawn on the egg, which fade over time as the paint gives up its stored energy.

[Jiri] exploits this by writing a variety of patterns onto the egg, which then animate in a manner similar to a zoetrope – when visualised under strobing light, the patterns appear to move. There are also a few holiday messages shown for Easter, making the egg all the more appropriate as a billboard.

If you like the idea of drawing on eggs but are put off by their non-uniform geometry, check out the Egg-bot. Video below the break.

Continue reading “Photochromic Eggs: Not for Breakfast”

Submersible Robots Hunt Lice With Lasers

De-lousing is a trying agricultural process. It becomes a major problem in pens which contain the hundreds of thousands of salmon farmed by Norwegians — the world’s largest salmon exporter — an environment which allows the parasite to flourish. To tackle the problem, the Stingray, developed by [Stingray Marine Solutions],  is an autonomous drone capable of destroying the lice with a laser in the order of tens of thousands per day.

Introduced in Norway back in 2014 — and some areas in Scotland in 2016 — the Stingray floats in the salmon pen, alert and waiting. If the lice-recognition software (never thought you’d hear that term, huh?) detects a parasite for more than two frames in the video feed, it immediately annihilates it with a 530 nanometre-wide, 100 millisecond laser pulse from up to two metres away. Don’t worry — the salmon’s scales are reflective enough to leave it unharmed, while the pest is fried to a crisp.  In action, it’s reminiscent of a point-defense laser on a spaceship.

Continue reading “Submersible Robots Hunt Lice With Lasers”

Two-Piece Boxes Thanks to Laser-Cut Flex Hinges

It sounds like a challenge from a [Martin Gardner] math puzzle from the Scientific American of days gone by: is it possible to build a three-dimensional wooden box with only two surfaces? It turns out it is, if you bend the rules and bend the wood to make living hinge boxes with a laser cutter.

[Martin Raynsford] clearly wasn’t setting out to probe the limits of topology with these boxes, but they’re a pretty neat trick nonetheless. The key to these boxes is the narrow to non-existent kerf left by a laser cutter that makes interference fits with wood a reality. [Martin]’s design leverages the slot and tab connection we’re used to seeing in laser-cut boxes, but adds a living flex-hinge to curve each piece of plywood into a U-shape. The two pieces are then nested together like those old aluminum hobby enclosures from Radio Shack. His GitHub has OpenSCAD scripts to parametrically create two different styles of two-piece boxes so you can scale it up or (somewhat) down according to your needs. There’s also a more traditional three-piece box, and any of them might be a great choice for a control panel or small Arduino enclosure. And as a bonus, the flex-hinge provides ventilation.

Need slots and tabs for boxes but you’re more familiar with FreeCAD? These parametric scripts will get you started, and we’ll bet you can port the flex-hinge bit easily, too.

Sudo Make Me a Sandwich

How do you like your Ham and Cheese sandwich? If you answered “I prefer it beefy”, look no further than [William Osman]’s Vin Diesel Ham and Cheese Sandwich! [Osman]’s blog tagline is “There’s science to do” but he is the first to admit this is science gone too far. When one of his followers, [Restroom Sounds], commented “Please sculpt a bust of [Vin Diesel] using laser cut cross-sections of laser sliced ham”, he just had to do it.

His friend [CameraManJohn] modeled the bust using Maya and [Osman] has provided links to download the files in case there’s the remote possibility that someone else wants to try this out. They picked the cheapest packs of sliced ham they could get from the supermarket — so technically, they did not actually laser slice the ham. For help with generating the slice outlines, they found the Slicer app for Autodesk’s Fusion 360 which did exactly what needed to be done. The app converts the 3D model into individual cross sections, similar to an MRI. It helps to measure the thickness of various samples of your raw material so that the Slicer output is not too stretched (or squished). The result is a set of numbered 2D drawings that can be sent to your laser cutter.

The rest of the video scores pretty high on the gross-o-meter, as [Osman] goes about laser cutting slices of ham (and a few slices of cheese), tasting laser cut ham (for Science, of course), and trying to prevent his computer from getting messed up. In the end, the sandwich actually turns out looking quite nice, although we will not comment on its taste. A pair of googly eyes adds character to the bust.

One problem is that the Slicer app does not optimise its results for efficient packing. with the smallest part occupying the same bounding box as the largest. This leads to a lot of wasted pieces of ham slices to be thrown away. [Bill] is still wondering what to do with his awesome sandwich, so if you have suggestions, chime in with your comments after you’ve seen the video linked below. If you know [Vin Diesel], let him know.

This isn’t [Osman]’s first adventure with crazy food hacks — here are a few tasty examples: a Toast-Bot that Butters For You (sometimes), a Laser-Cut Gingerbread Trailer Home, and a Pumpkin-Skinned BattleBot.

Continue reading “Sudo Make Me a Sandwich”