A More Conspicuous Computer Assistant

Back in the last century, especially in the ’40s to the ’60s, one of the major home decor trends was to install various home appliances, like the television or stereo, into its own piece of furniture. These were usually bulky, awkward, and incredibly heavy. And, since real life inspires art, most of the futuristic sci-fi technology we saw in movies and TV of the time was similarly conspicuous and physical. Not so with modern technology, though, where the trend now is to hide it out of the way and forget it exists. But [dermbrian] wanted some of his modern technology to have some of the mid-century visibility aesthetic so he made some modifications to his Amazon Echo.

The Echo itself remains largely unmodified, other than placing it inside a much larger cookie tin with some supporting electronics. For that, [dermbrian] found a relay board with a built-in microphone which switches the relay off when it detects sound so that when the Echo is activated, the sound from its speaker activates the module. From there it drives a series of blinkenlights which mimic the 60s computer aesthetic. Some custom fabrication and light diffusion methods were needed to get it to look just right, and a switch on the outside can disable the mechanism if it is getting triggered by background noise like music from his stereo.

While the appeal of this style may be lost on anyone who wasn’t a fan of the original Lost in Space, Star Trek, or Jetsons, it certainly holds a special significance for those who grew up in that era. It’s certainly not the first project we’ve seen to take a look back at the aesthetics of bygone eras, either. Take a look at this project which adds lenses to modern displays to give them the impression of antiquated CRT displays.

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Retro-Inspired Computer Case Hosts Mechanical Keyboard

During the time in the 1980s when the personal computer was gaining steam as a household fixture, plenty of models shipped with the keyboard built in to the machine itself. This helped reduce costs, lower the physical footprint of the device, and arguably improved aesthetics. But as technology progressed, this type of design fell by the wayside as computers became more modular and configurable. That’s not to say there aren’t any benefits to building a computer like this, though. [jit] is here to show off this Amiga-inspired computer with its own modern built-in mechanical keyboard.

Like the Raspberry Pi 400 which is built into its own case, modern computers like this are extremely portable, relatively simple, and space-efficient. But [jit] did not like the uninspired design of the Pi so he was looking to make some improvements. Starting with the keyboard, it boasts a 60% size board with mechanical keys which are backlit by LEDs. Inside the machine is a Odroid XU4 which has a little bit more power (and is often easier to find) than a comparable Raspberry Pi. The case is 3D printed and includes ventilation and support for the addition of various cooling fans, I/O ports, status LEDs, and switches for the computer inside.

Additionally, some modification of the Odroid itself was needed in order to move the various switches to the case, and the build also includes a somewhat customized power supply internally as well. It’s a well-rounded build that captures the spirit of the old computer cases, but takes advantage of a lot of modern technology at the same time. If you want to go all-out with a build like this, though, take a look at this retro-inspired case (with keyboard included) that manages to get most of a Framework laptop inside.

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A black work mat holds a circular badge with 64 addressable LEDs in a spiraling shape akin to the center of a sunflower. The LEDs have a rotating rainbow spiraling around the circle with red touching violet on one end. The colors extend in bands from the center to the rim of the circle.

Math You Can Wear: Fibonacci Spiral LED Badge

Fibonacci numbers are seen in the natural structures of various plants, such as the florets in sunflower heads, areoles on cacti stems, and scales in pine cones. [HackerBox] has developed a Fibonacci Spiral LED Badge to bring this natural phenomenon to your electronics.

To position each of the 64 addressable LEDs within the PCB layout, [HackerBox] computed the polar (r,θ) coordinates in a spreadsheet according to the Vogel model and then converted them to rectangular (x,y) coordinates. A little more math translates the points “off origin” into the center of the PCB space and scale them out to keep the first two 5 mm LEDs from overlapping. Finally, the LED coordinates were pasted into the KiCad PCB design file.

An RP2040 microcontroller controls the show, and a switch on the badge selects power between USB and three AA batteries and a DC/DC boost converter. The PCB also features two capacitive touch pads. [HackerBox] has published the KiCad files for the badge, and the CircuitPython firmware is shared with the project. If C/C++ is more your preference, the RP2040 MCU can also be programmed using the Arduino IDE.

For more details on beautiful RGB lights, we’ve previously presented Everything You Might Have Missed About Addressable LEDs, and for more details on why they can be so fun to wear, check out our Hackaday Badgelife Documentary.

(Editor’s note: HackerBox makes and sells kits, is run by Hackaday Contributor [Joseph Long] IRL.)

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Front and back views of a square, purple PCB with op amps and BNC outputs

Op Amp Contest: Generate Spirograph Shapes Using Only Op Amps And Math

If you’re a child of the ’80s or ’90s, chances are you’ve spent hours tracing out intricate patterns using the pens and gears of a Spirograph kit. Simple as those parts may be, they’re actually a very clever technique for plotting mathematical functions called hypotrochoids and epitrochoids. [Craig] has spent some time analyzing these functions, and realized you can also implement them with analog circuits. He used this knowledge to design a device called Op Art which generates Spirograph shapes on your oscilloscope using just a handful of op amps.

A spirograph shape shown on an oscilloscope screenTo draw either a hypotrochoid or an epitrochoid, you need to generate sine and cosine waves of various frequencies, and then add them with a certain scaling factor. Generating sines and cosines is not so hard to do with op amps, but making an adjustable oscillator that reliably churns out matching sine and cosine waves over a large frequency range turned out to be tricky. After a bit of experimentation, [Craig] discovered that a phase-shift oscillator was the right topology, not only for its adjustability but also because it generates sine, cosine and inverted sine terms that all come in handy when drawing various Spirograph shapes. Continue reading “Op Amp Contest: Generate Spirograph Shapes Using Only Op Amps And Math”

JITX Spits Out Handy USB Cable Tester

When USB first came on the scene, one of the benefits was that essentially any four conductors could get you to the point where you could send information at 12 Mbps. Of course everything is faster these days, and reaching today’s speeds requires a little bit more fidelity in the cables. This simple tester makes sure that your modern cables are actually up to the task.

One of the design goals of this project is to automate away the task of testing cables or finding one that works, especially before thinking a problem with a device is somewhere in software, spending hours or days debugging, before realizing that it’s actually being caused by a hardware malfunction. The small PCB has two USB-C fittings to plug in both of the ends of a cable to, and between those connectors there is a number of LEDs. Each LED is paired to one the many conductors within the USB cable, and not only does it show continuity of these conductors but it can also show a high resistance connection via a dimly-lit or off-color display from an LED.

One of the other interesting facets of this build is the use of JITX, which is a software-defined electronics CAD tool which allows PCB design to be automated by writing out the requirements of the PCB into code, rather than drawing it manually. It’s worth a look, and a lot of the schematics of this particular project as well as some discussion on this software can be found on the project’s GitHub page. Incidentally, if this tester looks familiar, it’s probably because your’re thinking of the open source hardware USB tester created by [Álvaro Prieto].

Mapping of the displacement of a tympanum of the lesser wax moth (Achroia grisella). (Credit: Andrew Reid)

3D Printing Bio-Inspired Microphone Designs Based On Moth Ears

If many millions of years of evolution is good for anything, it is to develop microscopic structures that perform astounding tasks, such as the marvelous biology of insects. One of these structures are the ears of the lesser wax moth (Achroia grisella), whose mating behavior involves ultrasonic mating calls. These can attract the bats which hunt them, leading to these moths having evolved directional hearing that can pinpoint not only a potential mate, but also bat calling sound.

What’s most astounding about this is that these moths that only live about a week as an adult can perform auditory feats that we generally require an entire microphone array for, along with a lot of audio processing. The key that enables these moths to perform these feats lies in their eardrum, or tympanum. Rather than the taut, flat surface as with mammals, these feature intricate 3D structures along with pores that seem to perform much of the directional processing, and this is what researchers have been trying to replicate for a while, including a team of researchers at the University of Strathclyde.

To create these artificial tympanums, the researchers used a flexible hydrogel, with a piezoelectric material that converts the acoustic energy into electric signals, connected to electrical traces. The 3D features are printed on this, mixed with methanol that forms droplets inside the curing resin, before being expelled and leaving the desired pores. One limitation is that currently used printers have a limited resolution of about 200 micrometers, which doesn’t cover the full features of the insect’s tympanum.

Assuming this can be made to work, it could be used for everything from cochlear implants to anywhere else that has a great deal of audio processing that needs downsizing.

(Heading image: Mapping of the displacement of a tympanum of the lesser wax moth (Achroia grisella). (Credit: Andrew Reid) )

Badminton Inspired Heat Shield Aims To Fly This Year

Badminton is not a sport that most of us think about often, and extremely rarely outside of every four years at the summer Olympics and maybe at the odd cookout or beach party here or there. But the fact that it’s a little bit unique made it the prime inspiration for this new heat shield design, which might see a space flight and test as early as a year from now.

The inspiration comes from the shuttlecock, the object which would otherwise be a ball in any other sport. A weighted head, usually rubber or cork, with a set of feathers or feather-like protrusions mounted to it, contributes to its unique flight characteristics when hit with a racquet. The heat shield, called Pridwen and built by Welsh company Space Forge, can be folded before launch and then expanded into this shuttlecock-like shape once ready for re-entry. It’s unlikely this will protect astronauts anytime soon, though. The device is mostly intended for returning materials from the Moon or from asteroids, or for landing spacecrafts on celestial bodies with atmospheres like Mars or Venus.

With some testing done already, Space Forge hopes this heat shield will see a space flight before the close of 2023. That’s not the end of the Badminton inspiration either, though. It’s reported that this device can slow a re-entering craft so much that it can be caught in a net. Not exactly the goal when playing the sport, but certainly a welcome return home for whichever craft might use this system. Of course, getting down from space is only half the battle. Take a look at this other unique spacecraft that goes up in a fairly non-traditional way instead.