[Zach] over at his channel Breaking Taps has put up an extraordinary account on manufacturing some homemade acrylic lenses. In the end, not only does he produce some beautiful concave lenses, he also covers the complete manufacturing process, from milling the aluminium die used for injection moulding to tweaking the parameters associated with injecting the actual acrylic, he even goes over the limitations of optics produced in this fashion.

What caught our eye in particular, was how [Zach] used the finished product to practically demonstrate photoelasticity originating from the stress induced by the moulding process. You might be familiar with describing the optical properties of a material by a single number, i.e its permittivity. But what happens if in addition to altering speed, the material also alters the polarisation and direction of light depending on the stress distribution within the material? Whilst a quantitative answer gets a bit complicated you can check out [Zach’s] additional videos to visualise the answer in a pretty and colourful way, without resorting to fancy computer simulations! If however, you really want to persist with the simulation route, check out our article on stress analysis in a totally different setting using Finite Element Analysis.

source https://hackaday.com/2020/07/07/milling-dies-and-injection-moulding-some-acrylic-lenses/

Stuck at home in self-quarantine, artist and filmmaker [Kira Bursky] had fewer options than normal for her latest film project. While a normal weekend film sprint would have involved collaborating with actors, set designers, and cinematographers in a frenzied attempt to finish in less than 48 hours, she instead chose to indulge in her curiosity for projection mapping, a technique that involves projecting visuals onto three-dimensional or flat surfaces.

In order for the images to properly map onto a surface, the surface first has to be mapped so that the projection is able to properly transform the flat image in order to produce the illusion of the light wrapping around the object. The technique is done in layers, in software similar to Photoshop, making it easier for the designer to organize the different interacting components in their animation.

[Kira] used a tool called Lightform to design her projections, which relies on a camera to calibrate the location of the surface and a projector to display the visuals. Her animated figures are drawn with loose lines and characterized by their slow gradients and ethereal movements. In the background of her film, a rhythmic sound plays while she brings the figures closer to view. Their outlines come into greater focus until the figures transform into her physical body, which also dances with the meandering lights.

Check out the short film below.

You can check out some other projects including video game projections, using a Raspberry Pi for projection mapping, and projection mapping onto moving surfaces.

source https://hackaday.com/2020/07/06/filmmaking-from-home-with-projection-mapping/

Some like to garden in their spare time, while others prefer to smoke cigars or fold complicated origami figurines. Security researcher [grifter] seems to enjoy cracking consoles instead, and had a go at exploiting the Nintendo 64 over an obscure modem interface.

The 1990s were a wild time, where games shipped in cartridges. This format opened up crazy possibilities to add additional hardware to the cartridge itself. Perhaps most famously, Nintendo packed in the SuperFX chip to enable 3D graphics on the Super Nintendo. Later on, the N64 game Morita Shogi 64 shipped with an entire telephone modem in the cartridge itself.  The resulting exploit is therefore dubbed “shogihax”.

Armed with a dodgy GameShark and a decompiler, [grifter] set to work. Through careful parsing of the code, they were able to find a suitable overflow bug in the game when using the modem. Unlike more pedestrian savegame hacks, this not only allowed for the execution of arbitrary code but also the modem interface means that it’s possible to continually stream more data to the console on an ad-hoc basis.

It’s a great hack that takes advantage of a relatively accessible cartridge, rather than relying on more obscure hardware such as the N64DD modem or other rarities. We’ve seen other N64 homebrew hacks before, too. Video after the break.

source https://hackaday.com/2020/07/06/remote-code-execution-on-the-n64/

A chaotic drone of meaningless sound to lull the human brain out of its usual drive to latch on to patterns can at times be a welcome thing. A nonsense background din — like an old television tuned to a dead channel — can help drown out distractions and other invading sounds when earplugs aren’t enough. As [mitxela] explains, this can be done with an MP3 file of white noise, and that is a solution that works perfectly well for most practical purposes. However he found himself wanting a more refined hardware noise generator with analog controls to fine tune the output, and so the Rumbler was born.

The Rumbler isn’t just a white noise generator. White noise has a flat spectrum, but the noise from the Rumbler is closer to Red or Brownian Noise. The different colors of noise have specific definitions, but the Rumbler’s output is really just white noise that has been put through some low pass filters to create an output closer to a nice background rumble that sounds pleasant, whereas white noise is more like flat static.

Why bother with doing this? Mainly because building things is fun, but there is also the idea that this is better at blocking out nuisance sounds from neighboring human activities. By the time distant music (or television, or talking, or shouting) has trickled through walls and into one’s eardrums, the higher frequencies have been much more strongly attenuated than the lower frequencies. This is why one can easily hear the bass from a nearby party’s music, but the lyrics don’t survive the trip through walls and windows nearly as well. The noise from the Rumbler is simply a better fit to those more durable lower frequencies.

[Mitxela]’s writeup has quite a few useful tips on analog design and prototyping, so give it a read even if you’re not planning to make your own analog noise box. Want to hear the Rumbler for yourself? There’s an embedded audio sample near the bottom of the page, so go check it out.

For a truly modern application of white noise, check out the cone of silence for snooping smart speakers.

source https://hackaday.com/2020/07/06/analog-noise-generator-fighter-of-other-noises/

We’ve all been there. You’re manning the battle station, deep in the sim-racing or some other n00b-pwning zone and suddenly some loudmouth blows out your eardrums over Discord. It’s insulting to have to stop what you’re doing to find the right Windows volume slider. So why do that? Build [T3knomanzer]’s simple yet elegant multi-volume knob and stay zen in the zone.

It’s easy, just turn the knob to cycle through your programs until Discord comes up on the little screen, and then push down to change it into a volume knob. If you need to change another volume, just click it again. Since there’s no Alt+Tabbing out to the desktop, no checkered flags should ever slip through your fingers.

Inside the well-designed case you’ll find the usual suspects — Arduino Nano, rotary encoder, an OLED display, and an LED ring, each with their own place carved out.

This completely open-source knob looks great, and we love that it’s been made incredibly easy to replicate by standing up a site with foolproof, well-depicted, step-by-step instructions. Watch them take it for a spin after the break.

Want more than volume at your fingertips? Here’s a DIY USB knob that does shortcuts, too.

source https://hackaday.com/2020/07/06/multi-volume-knob-gives-all-your-programs-a-turn/

The “Spin Cycle” is an amazing electric bicycle built using a motor salvaged from a washing machine; when the puns are this perfect you have to roll with them. [jimminecraftguy’s] creation is one of the most hacked-together yet functional electric vehicle we’ve seen in a long time.

The drive train of this bicycle starts with a brushless DC motor from a washing machine. It has been slightly modified to run on 48 volts, and is installed inside the triangle of the bike’s frame. It has a chain driving the bike’s crank, retaining the original chain and gearing setup (unlike many electric bike hacks that utilize hub motors). The crank has also been specially modified to include a freewheel, a necessary feature so that the motor can operate without spinning the pedals. Everything except the motor has been custom fabricated including the mounts and the electronics.

[jimminecraftguy] reports speeds of 110 kph which is a little crazy for a 20-year-old aluminum frame bike, and we’d guess it’s not street legal in many jurisdictions, but we can’t really find much fault with this build in general based on the amount of innovation required to get this working at all. A few more improvements for the build are in the works, including improved batteries and a cover for the sides to keep the local law enforcement from getting too suspicious. We can’t wait to see the final version.

source https://hackaday.com/2020/07/06/the-spin-cycle-washing-machine-motor-converts-10-speed-to-e-bike/

The gorgeous Shoji-style lamps you’re seeing here aren’t made of wood or paper. Beyond the LEDs illuminating them from within, the lamps are completely 3D printed. There aren’t any fasteners or glue holding them together either, as creator [Dheera Venkatraman] used authentic Japanese wood joinery techniques to make their components fit together like a puzzle.

While we’re usually more taken with the electronic components of the projects that get sent our way, we have to admit that in this case, the enclosure is really the star of the show. [Dheera] has included a versatile mounting point where you could put anything from a cheap LED candle to a few WS2812B modules, but otherwise leaves the integration of electronic components as an exercise for the reader.

All of the components were designed in OpenSCAD, which means it should be relatively easy to add your own designs to the list of included panel types. Despite the colorful details, you won’t need a multi-material printer to run them off either. Everything you see here was printed on a Prusa i3 MK3S in PETG. Filament swaps and careful design were used to achieve the multiple colors visible on some of the more intricate panels.

If the timeless style of these Japanese lanterns has caught your eye, you’ll love this beautiful sunrise clock we covered last year.

source https://hackaday.com/2020/07/06/elegant-shoji-lamps-from-your-3d-printer/

What if your microcontroller IDE was running on the microcontroller itself and not hosted on the computer you use to do the programming? The greatest legacy of Arduino in all its forms has arguably been a software one, in that it replaced annoying proprietary development environments with one that installed easily on a range of operating systems, was easy to use, and above all, worked. The next level of portability is to get rid of any specialize computer-side software. [Ronny Neufeld] wrote MicroIDE for ESP32 as an IDE accessible through a web browser, which interestingly is hosted on the target device itself.

Using the IDE is easy enough, install a binary, connect to the ESP with a web browser, start writing MicroPython code. There is a choice of connecting directly to the chip as a hotspot, or connecting via another WiFi network. The interface is looking pretty slick but he’s at pains to remind us that it’s a work in progress. Sadly there is no source code yet as it’s a binary distribution that is free for non-commercial use, we’d hope that an open-source release might one day happen. It’s not for everyone, but the convenience of accessing the same interface from almost any modern device should help attract a healthy community.

This appears to be the first web-based on-chip ESP IDE we’ve shown you. But it’s not the first on-chip coding example, as this BASIC interpreter shows.

[Main image source: Ubahnverleih / CC0]

source https://hackaday.com/2020/07/05/your-microcontroller-is-your-ide/