Kritik sah

We’ve all done it. We spy an old radio at a garage sale or resale shop. We know someone should bring it back to life, but it looks like a project, so we pass it by. Not [Ken] from [Ken’s Shop]. He found an Arvin 664A AM radio from 1947 in what appears to be a home-built cabinet and decided to bring it back to life. From what we could find, the original case was a white plastic, not the wood box it is in today. So the first challenge was simply getting inside to see what was going on. Inside is a pretty standard lineup of six tubes and a few transformers. There were obvious signs that someone had already been in there, as there were some new capacitors grafted in. What follows is the kind of troubleshooting you have to do when you are working with an old, unloved radio. Getting it powered up was most of the battle and required replacing all the old capacitors. The radio actually sounded good once it was working. With the box cleaned up, a new speaker grille, and a new wi...

The idea of FDM 3D printing using granules rather than filament is an appealing one: rather than having to wrangle spools of filament that need to adhere to strict dimensions and cannot be too flexible, you can instead just keep topping up a big hopper with fresh granules. This is what [HomoFaciens] has been tinkering with for a while now, with their Direct Granules Extruder V7.0 showing significant improvements . There’s also an accompanying article , with details of previous granule extruder attempts detailed on the same site. Many of the improvements here focus on making sure the granules melt properly before they reach the end of the extruder, with the auger screw helping to push things along. While this seems straightforward, there are many details to get right, with the previous v6.2 version having issues like the hot plastic backing up into the cold section and clogging things up. For the test bench a Prusa Mk4 FDM printer is used, with the standard extruder swapped for t...

There are all manner of musical synthesis techniques, from the early electromechanical instruments through analogue tape systhesis, the all-electronic waveform synthesisers of the 1960s onwards, and Yamaha’s FM systhesis of the 1980s, to name but a few. One of the attributes of such a machine lies in how many voices it has, or in simple terms, how many notes it can play simultaneously. Electronic complexity limited those early synths, but what happens on an FPGA where vast numbers of circuits can be made with little extra cost? [Tsuneo.Ohnaka] is pushing the envelope a little, by cramming 10240 individually controllable oscillators onto a Terasic DE10-nano FPGA board . While this thing can in theory generate 10240 different notes at once, in practice that doesn’t mean it has 10240 voices. Instead he calls it a spectrum engine, in that with such a large number of oscillators all with individually controllable frequency, phase, and amplitude, he’s made the part of all t...

Microplastics absolutely saturate the Earth’s environment, and that’s probably not a good thing unless you’re looking for a sediment marker for the Anthropocene period. On the other hand, environmental contamination only becomes a really big problem if it bioaccumulates– that is, builds up in the tissues of plants and animals. At least when it comes to worms, that’s not the case with microplastics, according to new research from the Canadian Light Source at the University of Saskatchewan. Pictured: Not an Igloo. Credit: David Stobbe / Stobbe Photography, via University of Saskatchewan The Canadian Light Source isn’t just some hoseheads in an igloo with a flashlight– it’s a 2.9 GeV Synchrotron tuned to produce high-energy photons. Back when Synchrotrons were used for particle physics, Synchrotron radiation was a very annoying energy sink, but nobody cares about 2.9 GeV electrons anymore. So rather than slam them into each other or a stat...

Even though the very concept of an ‘unpickable lock’ is as plausible as making water not be wet, this doesn’t take away from the intellectual thrill of devising solutions to picking attacks and subsequently circumventing those solutions. Case in point the ‘unpickable’ traveling key lock that [Works by Design] recently featured and sent a few copies off to lock pickers such as [Lock Noob] who gave picking it a shake . Many of the details and reasoning behind [Works by Design]’s lock design can be found in the original video , with [Lock Noob] going over the basic summary before getting to work trying to pick it. Rather than trying to bump the tumbler lock mechanism or another indirect approach, the focus is here on an impressioning attack. Although in this traveling key mechanism the physical key is moved inside the lock, the pins of the tumbler lock will leave impressions on the brass blanks when the lock is gently forced to rotate, indicating that ...

Electrostatic discharge machining (EDM) may be slower than alternatives like laser cutting, water jets, or a milling machine, but for some applications there’s no alternative: it can cut through any conductive material, no matter how hard, and it leaves no mechanical or thermal stress in the workpiece. Best of all, they’re relatively accessible for a resourceful hacker, such as [Inofid], who recently built the second iteration of his desktop wire EDM . The EDM’s motion system comes from a cheap desktop CNC router, which had a water tank mounted in its workspace and had the spindle replaced with a wire-management mechanism. The wire-management mechanism needs to continuously wind a tensioned brass wire from one spool through the cutting zone onto another spool. The tensioning system uses two motors: one to pull the wire through, and one to maintain tension by slightly counteracting it, with a tension sensor and Ardunio to maintain the proper tension. If it detects that the wire has br...