Raspberry Pi Pico Becomes MIDI-Compatible Synth

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?

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

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

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

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!

Hackaday Podcast Episode 249: Data By Laser And Parachute, Bluetooth Hacks, Google’s Gotta Google

‘Twas the podcast before Christmas, and all through the house, the best hacks of the week are dancing around Elliot and Tom’s heads like sugar-plums. Whatever that means.

I’d just like to interject for a moment. What you’re referring to as Christmas is, in fact, Happy/Holidays.

Before settling their brains in for a long winter’s nap, they’ll talk about the open source software podcast that now calls Hackaday home, the latest firmware developments for Google’s Stadia controller, high-definition cat videos from space, and upgrades for the surprisingly old-school battery tech that powers the Toyota Prius.

Out on the lawn, expect a clatter about the the state-of-the-art in DIY camera technology, the acoustic properties of hot chocolate, and a storage media from the 1990s that even Al Williams had never heard of.

Finally, after tearing open the shutters and throwing up the sash, the episode wraps up with a discussion about wiring techniques that let you leave the soldering iron at home, and the newest chapter in the long history of transferring data via parachute. Miniature sleigh and eight tiny reindeer sold separately.

Download the gift you really want this year: this week’s podcast in DRM-free MP3.

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Saving The Planet With Carefully Cut Paper

You may not think much of origami or its cousin-with-cutouts kirigami, but the latter could (and already is) helping to save the planet. But let’s back up a bit.

Most readers will be familiar with origami, the Japanese art of folding paper. But there is also kirigami, which uses a series of cuts to produce 3D shapes from 2D stock. Turns out that if you cut paper just right, you can turn it into highly-recyclable packaging that even interlocks with itself, negating the need for folding or even tape.

The video after the break takes a look at 3M’s Scotch Cushion Lock™ protective wrap through the eyes of its inventor, Tom Corrigan. It all started when 3M wanted to create a self-assembling box from a flat piece of cardboard.

So far, that particular invention hasn’t come to fruition, but after many long nights with paper and X-Acto knives, Tom came up with a honeycomb design with strong vertical walls that absorb energy much like bubble wrap or packing peanuts. The toothiness of each honeycomb wall adds height which adds strength, and allows the packaging to interlock with itself.

Not only is this packaging easier to recycle, it takes up way less space than other packaging alternatives. Once expanded, a 1,000 square foot roll of this stuff is equal to 2,500 square feet of bubble wrap, which constitutes about a dozen rolls.

Now, what to do about all that expanded polystyrene packaging still out there? With the right tool, you can turn it into insulation.

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