NASA’s Tech Demo Streams First Video From Deep Space Via Laser

December 19, 2023 by 46 Comments

Everyone knows that the most important part of a tech demo is to make the right impression, and the team over at NASA’s Jet Propulsion Laboratory (JPL) definitely had this part nailed down when they showed off streaming a cat video from deep space using laser technology as part of NASA’s Deep Space Optical Communication (DSOC) program. This system consists out of a ground-based laser transmitter and receiver along with a space-based laser transceiver, which for this experiment was positioned at a distance of 31 million kilometers – 80 times the distance between the Moon and Earth – as a part of the Psyche spacecraft.

After a range of tests with the system to shake out potential issues, the team found that they could establish a 267 Mbps link, with a one-way latency of a mere 101 seconds, allowing Psyche’s transceiver to transmit the preinstalled 15-second high-definition video in effectively real-time and making the cat Taters instantly world-famous. Although the potential for space-based cat videos cannot be underestimated, the main purpose of DSOC is to allow spacecraft to send back much larger data sets than they could before.

For robotic and potential future manned missions DSOC would mean high bandwidth video and data links, enabling more science, better communication and possibly the occasional cat video during interplanetary travel.

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Man playing custom zither made with a laser cutter.

Laser Cut Zither Instrument Kicks It Old World Style

December 14, 2023 by 4 Comments

Learning to play an instrument takes a certain level of dedication — and you can add another layer of dedication on top of that when it’s an instrument not found at your local Guitar Center. But it’s an entirely new level of dedication when someone crafts the instrument from scratch. If you’re looking for an example, check out this custom wooden zither [Nicolas Bras] built from laser cut parts.

The basic design of the instrument utilizes the sloted interlocking edges that are then glued together in lieu of traditional fasteners. Standard sized guitar tuning pegs and the accompanying steel guitar strings were then strung across two laser-cut bridges held in place by the string tension alone. The project began as way for [Nicolas] to learn the capabilities of his newly acquired laser cutter, but he himself is no amateur when it comes to constructing one-of-a-kind musical instruments. Just last year, he created a zither with bungee cords from the hardware store.

Zithers are German in origin, though some of the earliest zither-like instruments date back to 400 BCE China. The laser cut version [Nicolas] created had five strings to hammer on, though the type used in classical music arrangements typically contain upwards of thirty strings. The zither family of instruments may have given way to the electric guitars of today — it’s always neat to see new tech leveraged to embrace some old world charm.

For more on the art of DIY music production, check out this post on myriad of DIY musical instrument builds all played in concert.

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Homemade Raman Laser Is Shaken, Not Stirred

December 12, 2023 by 12 Comments

You wouldn’t think that shaking something in just the right way would be the recipe for creating laser light, but as [Les Wright] explains in his new video, that’s pretty much how his DIY Raman laser works.

Of course, “shaking” is probably a gross oversimplification of Raman scattering, which lies at the heart of this laser. [Les] spends the first half of the video explaining Raman scattering and stimulated Raman scattering. It’s an excellent treatment of the subject matter, but at the end of the day, when certain crystals and liquids are pumped with a high-intensity laser they’ll emit coherent, monochromatic light at a lower frequency than the pumping laser. By carefully selecting the gain medium and the pumping laser wavelength, Raman lasers can emit almost any wavelength.

Most gain media for Raman lasers are somewhat exotic, but luckily some easily available materials will work just fine too. [Les] chose the common solvent dimethylsulfoxide (DMSO) for his laser, which was made from a length of aluminum hex stock. Bored out, capped with quartz windows, and fitted with a port to fill it with DMSO, the laser — or more correctly, a resonator — is placed in the path of [Les]’ high-power tattoo removal laser. Laser light at 532 nm from the pumping laser passes through a focusing lens into the DMSO where the stimulated Raman scattering takes place, and 628 nm light comes out. [Les] measured the wavelengths with his Raspberry Pi spectrometer, and found that the emitted wavelength was exactly as predicted by the Raman spectrum of DMSO.

It’s always a treat to see one of [Les]’ videos pop up in our feed; he’s got the coolest toys, and he not only knows what to do with them, but how to explain what’s going on with the physics. It’s a rare treat to watch a video and come away feeling smarter than when you started.

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This Laser-Cut One-Piece Wedge Tenon Locks Wood Joints Tight

December 4, 2023 by 24 Comments

Woodworkers have always been very clever about making strong and attractive joints — think of the strength of a mortise and tenon, or the artistry of a well-made dovetail. These joints have been around for ages and can be executed with nothing more than chisels and a hand saw, plus a lot of practice, of course. But new tools bring new challenges and new opportunities in joinery, like this interesting “hammer joint” that can be made with a laser cutter.

This interesting joint comes to us from [Jiskar Schmitz], who designed it for quick, solid, joints without the need for glue or fasteners. It’s a variation on a wedged mortise and tenon joint, which strengthens the standard version of the joint by using a wedge to expand the tenon outward to make firm contact with the walls of the tenon.

The hammer joint takes advantage of the thin kerf of a laser cutter and its ability to make blind cuts to produce a tenon with a built-in wedge. The wedge is attached to a slot in the tenon by a couple of thin connectors and stands proud of the top of the tenon. The tenon is inserted into a through-hole mortise, and a firm hammer blow on the wedge breaks it free and drives it into the slot. This expands the tenon and locks it tightly into the mortise, creating a fairly bulletproof joint. The video below tells the tale.

While the hammer joint seems mainly aimed at birch plywood, [Jiskar] mentions testing it in other materials, such as bamboo, MDF, and even acrylic, although wood seems to be the best application. [Jiskar] also mentions a potential improvement: the addition of a ratchet and pawl shape between the wedge and the slot in the tenon, which might serve to lock the wedge down and prevent it from backing out.

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Take The Tedium Out Of Fabric Cutting, Make The Laser Do It

October 29, 2023 by 8 Comments

Fabric must be cut before it can be turned into something else, and [fiercekittenz] shows how a laser cutter can hit all the right bases to save a lot of time on the process. She demonstrates processing three layers of fabric at once on a CO2 laser cutter, cutting three bags’ worth of material in a scant 1 minute and 29 seconds.

The three layers are a PU (polyurethane) waterproof canvas, a woven liner, and a patterned cotton canvas. The laser does a fantastic job of slicing out perfectly formed pieces in no time, and its precision means minimal waste. The only gotcha is to ensure materials are safe to laser cut. For example, PU-based canvas is acceptable, but PVC-based materials are not. If you want to skip the materials discussion and watch the job, laying the fabric in the machine starts around [3:16] in the video.

[fiercekittenz] acknowledges that her large 100-watt CO2 laser cutter is great but points out that smaller or diode-based laser machines can perfectly cut fabric under the right circumstances. One may have to work in smaller batches, but it doesn’t take 100 watts to do the job. Her large machine, for example, is running at only a fraction of its full power to cut the three layers at once.

One interesting thing is that the heat of the laser somewhat seals the cut edge of the PU waterproof canvas. In the past, we’ve seen defocused lasers used to weld and seal non-woven plastics like those in face masks, a task usually performed by ultrasonic welding. The ability for a laser beam to act as both “scissors” and “glue” in these cases is pretty interesting. You can learn all about using a laser cutter instead of fabric scissors in the video embedded below.

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Retrotechtacular: The $175,000 Laser Printer

October 23, 2023 by 38 Comments

Laser printers today are cheap and readily available. But in 1976, they were the height of printing technology. The IBM 3800 was the $175,000 printer to have in that year. (Video, embedded below.) But you couldn’t have one on your desktop. Even if you could afford it, the thing is the size of a car, and we don’t even want to guess what it weighs. The printer took tractor-fed continuous form paper and could do 167 pages a minute at about 150 dots per inch (actually 180 x 144). For the record, that was as much as 1.7 miles of paper an hour!

In those days, people who would use this printer traditionally had massive banks of noisy impact printers. We imagine this device saved many data processing person’s hearing. Compared to a modern laser printer, though, it needed a lot of maintenance. For example, the initial models needed a xenon flash lamp replaced every month, although later models could go years on one bulb. Looking at some of the hardware in the video, it was probably made closer to the end of life for these printers which were made through 1999.

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Atomic Antenna Uses Lasers

October 21, 2023 by 12 Comments

If you think about it, an antenna is nothing more than a radio frequency energy sensor, or — more precisely — a transducer. So, it shouldn’t be a surprise that there could be different ways to sense RF that would work as an antenna. A recent paper in Applied Physics Letters explains an atomic antenna comprised of a rubidium vapor cell.

The interesting thing is that the antenna has no electrical components in the antenna, and can be located far away from the actual receiver. Instead of coax cables, the signal is read with a laser.

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