Digital Bike Horn Will Play Custom Sounds, Please Be Tasteful

December 23, 2023 by 19 Comments

When you’re out riding your bike, a horn can be a useful warning device to other road users and pedestrians alike. It can also be a source of fun and amusement, or annoyance, depending on the sounds it makes and how you use it. For the ultimate flexibility, you might like this digital bicycle horn that offers customizable sounds, as developed by [gokux].

The build has attractive two-tone components, consisting of a button pad for playing four sounds, and a sound module with a 3 watt speaker and battery pack. A Seeed Studio XIAO SAMD21 is the heart of the operation, with the microcontroller paired with a DFPlayer Mini which handles sound duties. When one of the four buttons is pressed, the microcontroller loads the relevant sound off an SD card, and plays it out over the speaker. For power, the build uses a lithium rechargeable battery with a healthy 1200 mAh capacity, which can be readily recharged thanks to a TP4056 charger module with a USB-C port.

It’s a nifty little build, and we love the Metal Gear Solid sounds. Though, we do wonder just how audible that 3 watt speaker is. If it proves inadequate, you could always step up to a much larger driver paired with a hefty audio amp if you so desire.

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UK’s JET Tokamak Retires After 40 Years And 105,842 Pulses

December 23, 2023 by 20 Comments

The UK’s most famous fusion reactor – the Joint European Torus (JET) tokamak – saw its first plasma on June 25th of 1983. Its final plasma pulse was generated on December 18th of 2023, for a total of 105,842 pulses over forty-and-a-half years and countless experiments.

Comparison of toroidal field (TF) coils from JET, JT-60SA and ITER (Credit: QST)
Comparison of toroidal field (TF) coils from JET, JT-60SA and ITER (Credit: QST)

Originally designed in the 1970s by Euratom members, JET formed the core of Europe’s fusion research program, allowing many of the aspects of tokamak systems to be explored, including deuterium-tritium fusion. Its final day of experiments involved an inverted plasma shape prior to targeting electrons at the tokamak’s inner wall, to study the impact of such damage.

Although JET has received a number of upgrades over the decades, the MAST Upgrade and upcoming STEP fusion reactors at the Culham Centre for Fusion Energy (CCFE) are now headed where JET’s design cannot go. Current advanced tokamak reactors like Japan’s JT-60SA are increasingly using super-conducting coils with  often plasma volumes far beyond JET’s, with the focus shifting from plasma research to net energy production.

This means that unless JET somehow gets repurposed/upgraded and recommissioned, this is the final goodbye to one of the world’s most famous and influential fusion reactors.

(Top image: Internal view of the JET tokamak superimposed with an image of plasma flows)

Raspberry Pi Pico Becomes MIDI-Compatible Synth

December 22, 2023 by 13 Comments

ECE 4760 is a microcontroller course that runs at Cornell every year, and it gives students a wide remit to pursue various kinds of microcontroller projects. [Pelham Bergesen] took the class and built himself a MIDI-controllable synthesizer out of a Raspberry Pi Pico.

[Pelham] coded a library to parse MIDI messages on the Pico, with the microcontroller’s UART charged with receiving the input data. MIDI is basically just serial at a baud rate of 31.25k, with a set message structure, after all. From there, the Pico takes the note data and plays the relevant frequencies by synthesizing square waves using a PWM output. A second PWM channel can also be blended with the first to generate more complex tones.  The synthesizer is designed to be used with a source of MIDI note data such as a keyboard controller; [Pelham] demonstrates the project in use with a Roland JD-XI. It’s a fairly basic synthesizer, but [Pelham] does a good job of explaining all the steps required to get this far. If you’ve never done an audio or MIDI project before, you might find his guide very helpful for the way it steps through the basics.

[Pelham] didn’t get to implement fancier features like direct digital synthesis (DDS) or analog audio effects before the class closed out. However, that would be an excellent project for anyone else developing their own Pico synthesizer. If you whip up something that sounds good, or even just interesting, be sure to notify us on the tipsline. Video after the break.

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Will We Recycle FPGAs In The Future?

December 22, 2023 by 21 Comments

If you really want to look at how much something costs, you need to look at total cost of ownership, not just the sticker price. Same goes for things like pollution and carbon footprint. A vehicle, for example, might have a low carbon footprint in operation but require more carbon in the manufacturing or disposal processes. Researchers have noted that FPGA accelerators get replaced and may wind up as e-waste in as little as two years. They propose REFRESH, an architecture that recycles old FPGAs into new ones by joining multiple FPGA dice with a simple interposer to coordinate the work.

The idea is not as radical as it might first seem. Many modern chips use chiplets anyway, so this is a reasonable extension of that idea. You simply need a way to harvest the old devices.

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Spice Up Your Earrings With Microelectronics

December 22, 2023 by 9 Comments

We’ve covered [mitxela] in the past and if you know him, you’ll likely know him for putting the micro in microelectronics. This year, he’s at it again with his LED Industrial Piercing.

A T-shaped flexible PCB that is smaller than an index finger
This tiny PCB is really pushing the limits of fabrication

Inspired by the absolutely tiny 0402 LEDs and industrial piercings, [mitxela] started thinking of a way to construct the 5cm long device. He found some normal LED earrings to steal the battery compartment from. Then, with a tick needle and some more steel, he created a new industrial earring with some holes.

Of course, no [mitxela] project is complete without comically tiny microsoldering and this project makes the VQFN ATTiny he used look large. He puts his PCB suppliers to the test with a merely 1mm wide flex PCB for the LEDs to be mounted on. Finally, he combines the flex PCB, the earring and some epoxy to create yet another piece of LED jewelry.

Video after the break.
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$30 Guitar Build Shows What You Can Do With Amazon Parts

December 22, 2023 by 20 Comments

Most guitarists buy their axes fully assembled from big names like Fender, Gibson, and… maybe Yamaha? Sure. But there are a dedicated set that relish in mixing and matching parts and even building and assembling their own instruments. [Danny Lewis] decided to see what he could do with the cheapest guitar parts from Amazon and a body of his own design, and he put together something pretty passable for just $30.

The wood for the body was cut on a bandsaw, and was essentially free scrap sourced from old furniture. [Danny] went for an unconventional design using a roughly Telecaster outline and large cutouts either side of the bridge. The neck was free, by virtue of being an old Harmony neck sourced off Craigslist. We’d have preferred to see what could be done with a cheap Amazon neck, but it nonetheless fits the vibe of the build.

The guitar then received a $9.99 pickup and controls, an $8.80 solidtail bridge, and $11 tuning machines for the headstock. Strung up, it actually sounds passable. We’d want to throw it on a proper amp and give the whole thing a setup before fully assessing it, but hey, for $30, it’s hard to go wrong.

We do love some hacky guitars around here; we’ve even featured some with surprise effects gear built into the bodies. Video after the break.

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Ultra-Basic Thermal Camera Built Using Arduino Uno

December 22, 2023 by 17 Comments

Thermal cameras can cost well into the five-figure range if you’re buying high-resolution models with good feature sets. New models can be so advanced that their export and use is heavily controlled by certain countries, including the USA. If you just want to tinker at the low end, though, you don’t have to spend a lot of scratch. You can even build yourself something simple based on an Arduino Uno!

The build uses Panasonic’s cheap “Grid-EYE” infrared array as the thermal sensor, in this case, a model with an 8×8 array of thermopiles. It’s not going to get you any fancy images, especially at long range, but you can use it to get a very blocky kind of Predator-vision of the thermal radiation environment. It’s a simple matter of hooking up the Grid-EYE sensor to the Arduino Uno over I2C, and then spitting out the sensor’s data in a nice visual form on a cheap TFT screen.

It’s a great introduction to the world of thermal imaging. There’s no better way to learn how something works by building a working example yourself. We’ve featured a few similar projects before, too; it’s all thanks to the fact that thermal sensors are getting cheaper and more accessible than ever!