Recycling Soda Bottles Into Filament To Print Smaller Soda Bottles

Thermoplastics are great, because you can melt them down and reform them into whatever you like. This is ably demonstrated by [The Q] by recycling old soda bottles into usable 3D printer filament.

Cute, huh? Why aren’t Coca-Cola making these? Tiny fake grocery items already proved hugely popular in Australia.

Soda bottles are usually made out of PET plastic, or polyethylene terephthalate, which is one of the most popular thermoplastics in modern society. A soda bottle can be cut into a continuous long, thin strip with the use of a simple hand-operated machine that slices the bottle with a blade. This strip of plastic can then be fed through a heated nozzle in order to produce filament for 3D printing. [The Q] demonstrates both parts of this process, including using a motorized reel to take up filament as the bottle material is fed through the extruder.

The filament is then demonstrated by printing tiny versions of soda bottles. [The Q] fills these with soda and gives them the appropriate lids and labels for completion’s sake. It’s a neat way to demonstrate that the filament actually works for 3D printing. It bears noting that such prints are almost certainly not food safe, but it’s really a proof of concept rather than an attempt to make a usable beverage container.

Like similar builds we’ve seen in the past, the filament is of limited length due to the amount of plastic in a single bottle. We’d like to see a method for feeding multiple bottles worth of plastic into the extruder to make a longer length spool, as joining lengths of filament itself can be fraught with issues. Video after the break.

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The Eerie Sounds Of Ioalieia: An ESP32/Valve/Analog Hybrid Circuit Sculpture

We’ve not had a circuit sculpture piece for a while, so here’s “ioalieia” a lovely hybrid digital-analog sound sculpture by [Eirik Brandal] to dig into.

Tidy straight lines. Nice job!

The host of the show is the ESP32 module, which generates audio frequency square waves, which are fed into a MCP4251 digital potentiometer. From there, it is fed into a AS3320 Voltage controlled filter (VCF), from Latvia-based ALFA (which is new to us, despite them being manufacturing electronics for sixty years!) This is an interesting device that has a four independently configurable filter elements with voltage controlled inputs for frequency control and resonance. The output from the VCF is then fed into a 6n2p (Soviet equivalent to the 12ax7) twin-triode vacuum tube, which is specifically aimed at audio applications.

The suitably distorted filtered square waves then pass into a Princeton Tech Corp PT2399 echo processor chip, which being digitally constructed, uses the expected ADC/RAM/DAC signal chain to implement an audio echo effect. As with the VCF, the echo depth can be modulated via the digipot, under the ESP32’s command. For a bit of added bling, the vacuum tube output feeds back into the ESP32, to be consumed by the internal ADC and turned into a light show via some PWM controlled LEDs. Lovely.

The final audio output from the echo chip is then fed into a speaker via a pair of LM380 amplifiers giving a power of about 5 W. It sounds pretty good if you ask us, and software configurable via Wi-Fi, giving this sculpture plenty of tweakabilty.

Of course circuit sculpture come in all shapes and sizes, and it wouldn’t do to not mention at least one sculpture clock project, and while we’re on it, here’s last year’s Remoticon circuit sculpture workshop.

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Hacking Is Hacking

Tom Nardi and I had a good laugh this week on the Podcast when he compared the ECU hacks that enabled turning a VW with steering assist into a self-driver to a hack last week that modified a water cooler to fill a particular cup. But it’s actually no joke — some of the very same techniques are used in both efforts, although the outcome of one is life-and-death, and the other is just some spilled ice-cold water.

This reminded me of Travis Goodspeed’s now-classic talk “In Praise of Junk Hacking” from way back in 2016. For background, this was a time when IoT devices and their security were in their relative infancy, and some members of the security community were throwing shade on the dissection of “mere” commercial crap. (Looked back on from today, where every other member of a Botnet is an IP camera, that argument didn’t age well.)

Travis’ response was that hacking on junk lets us focus on the process — the hack itself — rather than getting distracted by the outcome. Emotions run high when a security flaw affects millions of individuals, but when it’s a Tamagotchi or a pocket calculator, well, it doesn’t really matter, so you focus on the actual techniques. And as Travis points out, many of these techniques learned on junk will be useful when it counts. He learned about methods to defeat address-space randomization, for instance, from an old hack on the TI-85 calculator, which garbage-collected the variables that needed to be overwritten.

So I had junk hacking in the back of my mind when I was re-watching Hash Salehi’s great talk on his work reverse engineering smart meters. Funnily enough, he started off his reverse engineering journey eleven years ago with work on a robot vacuum cleaner’s LIDAR module. Junk hacking, for sure, but the same techniques taught him to work on devices that are significantly more serious. And in the craziest of Hackaday synergies, he even hat-tipped Travis’ talk in his video! Hacking is hacking!

555 timer circuit for the contest

Doing The Right Thing The Wrong Way: Dumping STM8 Firmware With 555 Timers

When [Jarrett] decided to enter the 555 Contest that’s just wrapped up, he leaned up on an idea that’s been rattling around in his noggin for a few years: Using 555 timers to trigger a firmware dump on a microcontroller. It’s definitely the wrong tool for the job, but [Jarrett] got it working and documented it nicely at Hackaday.io.

The premise is that by interrupting the power supply to the STM8 microcontroller at just the right time and for just the right duration, it would skip the instruction telling it not to allow its firmware to be read. Time and duration… things the 555 is well known for being capable of. There was a problem, however.

The first problem is that the duration was to be measured in nanoseconds. A garden variety 555 has can only pulse down to about 10 microseconds. The solution? Well, you’ll have to read the excellent project page to find out, but don’t worry- it’s a 555. The second problem? He was using 555’s!

Was [Jarrett] successful? After much fiddling and twiddling, he absolutely was! The old firmware was dumped from the STM8 processor and the new firmware could be flashed with impunity.

This 555 contest has seen some truly epic entries, including but not limited to this 555 based accordion like instrument that this particular author just can’t get enough of!

 

Improve Your Front Panels

For many of us, the bane of electronic projects is making a professional-looking enclosure. Sure, 3D printing has made it easier to make the actual enclosure, but there’s still the problem of labeling it. [Richard Langner] has the answer with something he calls easy front panels. You can read about it or watch the tutorial video below.

The concept is easy enough. You create your beautiful artwork in your choice of graphics programs. The example uses Inkscape, but you could do it in anything, even PowerPoint. You print it out and cut it to size. You could, of course, print it in color or — as the example does — color it in by hand.

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Travel Guitar Hacked With Digital FX Setup

[Courcirc8] was a big fan of the ALP AD-80, with the travel guitar being a surprisingly competent instrument despite its folding form-factor. However, the onboard headphone amp left something to be desired, so it was time to get hacking.

To achieve better audio output, [courcirc8] decided to purchase an iRig HD 2 guitar interface, and installed it inside the body of the compact guitar. The original volume pot on the guitar was instead spliced into the iRig circuit, and a switch hooked up to allow the guitar to output clean tones to an amp or the digital audio output of the iRig instead. It’s a tight fit inside, but it all nestles in there rather neatly when finished.

The result is a compact guitar that has a capable digital FX platform built in to the body; all one has to do is hook up a smartphone to gain access to a broad selection of software effects.  It makes the guitar much more of a Swiss Army knife when playing on the road.

We’ve seen others before installing guitar effects into the instrument itself; it remains perhaps one of the best ways a hacker can express themselves with a completely individual instrument!

Smart Sutures Become WiSe

A team at the Wireless Bioelectronics Lab at the National University of Singapore led by [Dr John Ho] announced the results of their new Wireless Sensing (WiSe) smart sutures program last month. Their system consists of a specially prepared patch of polymer gel (the sensor) which is sewn into the wound using a silk suture coated with a conductive polymer. An external reader scans the sensor to monitor the status of the wound.

The concept is not unlike a NFC public transportation card, although with simplified electronics. There is no microcontroller or digital data being transferred. Rather, the sensor behaves like a tuned tank. The gel on the sensor was designed to degrade if the wound becomes infected, changing capacitance of the sensor structure and thus shifting its resonant frequency.

If you’ve ever had the misfortune to experience surgery, no doubt the surgeon and nurses drove home the importance of diligent monitoring of the wound for early signs of infection. These smart sutures allow detection of wound infection even before symptoms can seen or felt. They can be used on internal stitches up to 50 mm inside the body. More details can be read in this paper, and we covered another type of smart sensor back in 2016.