Lasers are optical amplifiers, optical oscillators, and in a way, the most sophisticated light source ever invented. Not only are lasers extremely useful, but they are also champions of magnitude: While different laser types cover the electromagnetic spectrum from radiation (<10 nm) over the visible spectrum to far infrared light (699 μm), their individual output band can be as narrow as a few µHz. Their high temporal and spatial coherence lets them cover hundreds of meters in a tight beam of lowest divergence as a perfectly sinusoidal, electromagnetic wave. Some lasers reach peak power outputs of several exawatts, while their beams can be focused down to the smallest spot sizes in the hundreds and even tens of nanometers. Laser is the acronym for Light Amplification by Stimulated Emission Of Radiation, which suggests that it makes use of a phenomenon called stimulated emission, but well, how exactly do they do that? It’s time to look the laser in the eye (Disclaimer: don’t!).
For almost two decades there has been research that describes a method to freeze material with nothing but a laser. The techniques have only ever been able to work on single nano-crystals in a vacuum, making it less than functional — or practical. Until now, that is.
Researchers at the University of Washington have figured out how to cool a liquid indirectly using an infrared laser. It works by subjecting a special microscopic crystal to the laser. When the laser hits this crystal, the infrared light turns to the visible spectrum, becoming a reddish green light — which happens to be more energetic than infrared. This shift in energy levels is what causes a change in temperature. The energy (in the way of heat) is sucked from the fluid surrounding the crystal, and as such, causes a drop in the temperature of the liquid. Continue reading “Freezing Stuff With Fricken’ Lasers”
[jrcgarry] hacked together this awesome interferometer which is able to measure displacements in the nanometer range. Commercial interferometers are used in research labs to measure tiny displacements on the nanometer scale, and can cost tens of thousands of dollars. [jrcgarry] used beam splitters from BluRay drives, mirrors from ebay and a 5mw laser diode.
We’ve covered the use of interferometers before. But never an instrument built from scratch like this. Interferometers exploit the wave-like nature of a beam of light. The beam is split and sent down two separate paths, where the beams bounce off mirrors to return to the beam splitter to be recombined. Because of its wave light nature the beams will interfere with each other. And as the beams have traveled different distances they may be in or out of phase. Resulting in either constructive (brighter) or destructive (darker) interference.
Because the wavelength of light is on the order of 100s of nanometers, by observing the interference patterns you can monitor the displacement of the mirrors with respect to each other at nanometer resolution. [jrcgarry] doesn’t use the interferometer for any particular application in this tutorial but it’s a great demonstration of the technique!
Making a Space Invaders game is up there on the list of most unconventional things you could do with a laser cutter. In watching the tiny little ships burst into flames, [Martin Raynsford’s] modification has got to be one of the more dangerous looking ones we’ve seen as well.
[Martin] always had the desire to make a tangible version of the classic game. Since his Whitetooth A1 laser cutter already contained the bulk of the moving hardware needed, not to mention an actual high powered laser to “pew pew” with, he decided it was the perfect starting point for such a project. The game is played looking down into the cutter since the laser of course fires in that direction, however a basic webcam is mounted to the laser assembly so that you can view the game on a computer screen at the proper perspective. An Arduino Mini is responsible for stepper control, allowing the player to jog back and forth and fire with a keyboard. [Martin] added an extra gear to the z-axis bed-leveler so that it could drive rows of paper invaders left and right across the bottom. Paperclips wedged into slots along a modified backboard hold each of the paper slips in place. This works ideally since they can be reloaded easily and won’t be maimed during use.
Due to the heat of the laser, landing a well positioned shot will likely nuke all of the nearby invaders as well, making for a theatrical inferno and easy win. Now to step up the difficulty level and figure out how to make them fire back…
[Apachexmd] wanted to do something fun for his three-year-old son’s birthday party. Knowing how cool race cars are, he opted to build his own Hot Wheels drag race timer. He didn’t take the easy way out either. He put both his electronics and 3D printing skills to the test with this project.
The system has two main components. First, there’s the starting gate. The cars all have to leave the gate at the same time for a fair race, so [Apachexmd] needed a way to make this electronically controlled. His solution was to use a servo connected to a hinge. The hinge has four machine screws, one for each car. When the servo is rotated in one direction, the hinge pushes the screws out through holes in the track. This keeps the cars from moving on the downward slope. When the start button is pressed, the screws are pulled back and the cars are free to let gravity take over.
The second component is the finish line. Underneath the track are four laser diodes. These shine upwards through holes drilled into the track. Four phototransistors are mounted up above. These act as sensors to detect when the laser beam is broken by a car. It works similarly to a laser trip wire alarm system. The sensors are aimed downwards and covered in black tape to block out extra light noise.
Also above the track are eight 7-segment displays; two for each car. The system is able to keep track of the order in which the cars cross the finish line. When the race ends, it displays which place each car came in above the corresponding track. The system also keeps track of the winning car’s time in seconds and displays this on the display as well.
The system runs on an Arduino and is built almost exclusively out of custom designed 3D printed components. Since all of the components are designed to fit perfectly, the end result is a very slick race timer. Maybe next [Apachexmd] can add in a radar gun to clock top speed. Check out the video below to see it in action. Continue reading “DIY Hot Wheels Drag Race Timer”
This week’s Hacklet is all about lasers, which have been shining a monochromatic light for hackers since 1960. The first working laser was demonstrated by [Theodore Maiman], who was a hacker / maker himself, having learned circuits in his father’s home electronics lab. It’s no surprise that lasers have been hugely popular in the hacker community ever since.
[Maiman’s] first laser was pumped with flash tubes, which is similar to the YAG laser in [macona’s] project to restore a laser welder. He’s gotten his hands on a 1985 model 400W Lumonics laser welder. This welder was originally bought by Tektronix to weld titanium CRT flanges. Time moved on, and the welder was sold to [macona’s] company, who used it until the Anorad control system died. There was an effort to bring it up to date with new servos and an OpenCNC control system, but the job was never finished. This laser sat for 12 years before [macona] bought it, and now he’s bringing it back to life with LinuxCNC. The project is off to a blazing start, as he already has the laser outputting about 200 Watts.
On the slightly lower power side of things we have [ThunderSqueak’s] 5mW visible red (650nm) laser. [ThunderSqueak] needed an alignment laser with decent focusing optics for her other projects. She mounted a module in a plastic case and added a switch. A quick build, but it’s paying dividends on some of her bigger projects – like her Low Cost CO2 Laser Build, which we featured on the blog back in May.
[phil] used buildlog 2.x as the inspiration for his Simple DIY laser cutter. The laser power comes from a low cost K40 laser tube and head. His frame is aluminum extrusion covered with Dibond, an aluminum composite material used in outdoor signs. Locomotion comes from NEMA 17 stepper motors. Many of [phil’s] parts are machined from HDPE plastic, though it looks like they could be 3D printed as well. We bet this one will be a real workhorse when it’s done.
[ebrithil] is working on a combo laser engraver/PCB etcher which will use a solid state laser module. His layout is the standard gantry system seen on many other mills and 3D printers. Dual steppers on the Y axis increase avoid the need for a central belt. His Z axis was donated by an old DVD drive. It has enough power to lift a pen, and should be plenty accurate for focusing duty. He’s already run a couple of great tests with a low power violet laser and glow in the dark material.
[Mario] is creating an incredibly versitile laser tool in his OpenExposer, which can do everything from stereolithography 3D printing to making music as a laser harp. The genius here is [Mario’s] reuse of laser printer parts. Every laser printer uses the same basic setup: a laser, a scanning mirror, and optics to stretch the beam out to a full page width. [Mario] is already getting some great prints from OpenExposer. This project is one to watch in The Hackaday Prize.
[fl@C@] is digging into the physics side of things with his DIY 3D Printable RaspberryPi Raman Spectrometer. Raman Spectrometers are usually incredibly expensive pieces of requirement which can tell us which elements make up a given material sample. [fl@C@’s] laser is a 532nm 150mW laser, which bounces through a dizzying array of mirrors and lenses. The resulting data is crunched by a Raspberry Pi to give a full spectrographic analysis. [fl@C@’s] entered his project in The Hackaday Prize, and we featured his bio back in June.
The third issue of The Hacklet has been released. In this issue, we start off with a roundup on the Sci-Fi Contest which recently concluded. After seeing the many great hacks you came up with for that contest, we’re looking forward to seeing what you think of for The Hackaday Prize.
Next up, we take a look at two hacks that deal with switching mains, which is a feature that most home automation projects need. These high voltage switches can be dangerous to build, but one hack finds a safe and cheap way to do it. The next looks at building your own high voltage circuitry.
Finally, we talk about two laser hacks. The first is practical: a device for exposing resins and masks using a laser. The second is just a really big laser, built from hardware store parts. Who doesn’t like big lasers? We definitely like big lasers, and so does the FAA.