Hackaday editors Elliot Williams and Mike Szczys marvel at the dangerous projects on display this week, including glass etching with hydrofluoric acid and pumping 200,000 A into a 5,000 A fuse. A new board that turns the Raspberry Pi into an SDR shows off the power of the secondary memory interface (SMI) present in those Broadcom chips. We also discuss the potential for graphene in hard drives, and finish up with a teardown of a very early electronic metronome.
Update 6/23/21: Many people have called this out as fake. When viewed at 1/4 speed, you can see the logos in the YouTube video are always full-off or full-on and never caught mid way through a scanned frame. The images may be projected from off-camera to the left, rather than by the diode behind the screen. It’s a neat idea, but on closer review the demo provided smells a bit fishy so we’ve added a “Real or Fake” tag and updated the title. Update #2: [Kanti Sharma] wrote into the tipsline apologizing for the faked video, saying that he tried to get it to work but couldn’t and then “used a phone and a lens to fake the laser”. Thanks for fessing up to this one.
There are some times when an awesome project comes into your feed, but a language barrier intervenes as you try to follow its creator’s description. [Kanti Sharma]’s laser display appears to be a fantastic piece of work, but YouTube’s automatic translations in the video below make so little sense as to leave us Anglophones none the wiser as to what he’s saying. The principle comes across without need for translation though: he’s taken a laser diode module and is using it to create a vector scan by mounting it in the middle of a set of coils driven through beefy FETs by an Arduino. It’s an electromagnetic take on the same principle used in a CRT vector displays such as the famous Vectrex console, with the beam of electrons replaced with laser light.
It’s a technique not unlike what’s been used for years in the lighting industry, in which much larger laser displays are created with mirrors mounted on galvanometers. There must be a physical limit at which the weight of the laser slows down the movement, but if the video is to be believed it’s certainly capable of displaying graphics on a screen.
People have done a lot of things with lasers on these pages, but there have been surprisingly few vector displays using them. Here’s one from nearly a decade ago.
A couple months back, [macona] got his hands on a 300 watt Rofin CO2 laser in an unknown condition. Unfortunately, its condition became all too known once he took a peek inside the case of the power supply and was confronted with some very toasty components. It was clear that the Magic Smoke had been released with a considerable bit of fury, the trick now was figuring out how to put it back in.
The most obvious casualty was an incinerated output inductor. His theory is that cracks in the ferrite toroid changed its magnetic properties, ultimately causing it to heat up during high frequency switching. With no active cooling, the insulation cooked off the wires and things started to really go south. Maybe. In any event, replacing it was a logical first step.
If you look closely, you may see the failed component.
Unfortunately, Rofin is out of business and replacement parts weren’t available, so [macona] had to wind it himself with a self-sourced ferrite and magnet wire. Luckily, the power supply still had one good inductor that he could compare against. After replacing the coil and a few damaged ancillary wires and connectors, it seemed like the power supply was working again. But with the laser and necessary cooling lines connected, nothing happened.
A close look at the PCB in the laser head revealed that a LM2576HVT switching regulator had exploded rather violently. Replacing it wasn’t a problem, but why did it fail to begin with? A close examination showed the output trace was shorted to ground, and further investigation uncovered a blown SMBJ13A TVS diode. Installing the new components got the startup process to proceed a bit farther, but the laser still refused to fire. Resigned to hunting for bad parts with the aid of a microscope, he was able to determine a LM2574HVN voltage regulator in the RF supply had given up the ghost. [macona] replaced it, only for it to quickly heat up and fail.
This one is slightly less obvious.
Now this was getting ridiculous. He replaced the regulator again, and this time pointed his thermal camera at the board to try and see what else was getting hot. The culprit ended up being an obsolete DS8922AM dual differential line transceiver that he had to source from an overseas seller on eBay.
After the replacement IC arrived from the other side of the planet, [macona] installed it and was finally able to punch some flaming holes with his monster laser. Surely the only thing more satisfying than burning something with a laser is burning something with a laser you spent months laboriously repairing.
Remember the pistol controller for the original Atari 2600? No? Perhaps that’s because it never existed. But now that we’re living in the future, adding a pistol to the classic games of the 2600 is actually possible.
Possible, but not exactly easy. [Nick Bild]’s approach to the problem is based on machine vision, using an NVIDIA Xavier NX to run an Atari 2600 emulator. The game is projected on a wall, while a camera watches the game field. A toy pistol with a laser pointer attached to it blasts away at targets, while OpenCV is used to find the spots that have been hit by the laser. A Python program matches up the coordinates of the laser blasts with coordinates within the game, and then fires off a sequence of keyboard commands to fire the blasters in the game. Basically, the game plays itself based on where it sees the laser shots. You can check out the system in the video below.
It’s difficult to tell with our dull human senses, but everything around us is vibrating. Sure it takes more energy to get big objects like bridges and houses humming compared to a telephone pole or mailbox, but make no mistake, they’ve all got a little buzz going on. With their new automated laser, the team behind VibroSight++ believes they can exploit this fact to make city-scale sensing far cheaper and easier than ever before.
The key to the system is a turret mounted Class 3B infrared laser and photodetector that can systematically scan for and identity reflective surfaces within visual range. Now you might think that such a setup wouldn’t get much of a signal from the urban landscape, but as it so happens, the average city block is packed with retroreflectors. From street signs to road studs and license plates, the team estimates dense urban areas have approximately 7,000 reflectors per square kilometer. On top of those existing data points, additional reflectors could easily be added to particularly interesting devices that city planners might want to monitor.
Once VibroSight++ has identified its targets, the next step is to bounce the laser off of them and detect the minute perturbations in the returned signal caused by vibrations in the reflector. In the video below you can see how this basic concept could be put to practical use in the field, from counting how many cars pass over a certain stretch of road to seeing how popular a specific mailbox is. There’s a whole world of information out there just waiting to be collected, all without having to install anything more exotic than the occasional piece of reflective tape.
You’ve seen it a million times in science fiction movies and TV shows: a moving holographic display. From Princess Leia asking for help to virtual tennis on Total Recall, it is a common enough idea. [Dan Smalley]’s team at BYU has made progress in projecting moving 3D images in thin air. While they might not be movie quality, they are a start, and, after all, you have to start somewhere.
The display traps a small particle in the air with a laser beam and then moves that particle around, leaving behind an illuminated path in the air. You can see the effect in the video below. The full paper explains how a type of ray tracing allows the relatively small optical trap display to appear larger and more fluid. While it does make images seem to appear behind the display’s actual volume, it also requires eye tracking to work since the illusion only works from a certain perspective.
These are not, of course, technically holograms. That’s actually an advantage in some cases because holograms require a tremendous amount of data that increases rapidly as the size of a display scales up. The optical trap display uses a much more manageable data rate.
Lasers do all sorts of interesting things and — as with so many things — more is better. Korean scientists announced recently they’ve created the most powerful laser beam. 1023 watts per square centimeter, to be exact. It turns out that 1022 Watts/cm2 may not be commonplace, but has been done many times already at several facilities, including the CoReLS petawatt (PW) laser used by the researchers.
Just as improving a radio transmitter often involves antenna work instead of actual power increases, this laser setup uses an improved focus mechanism to get more energy in a 1.1 micron spot. As you might expect, doing this requires some pretty sophisticated optics.
