The Best-Sounding Walnut You’ll Hear Today

November 2, 2023 by 16 Comments

Do you ever find yourself eating walnuts and think, this would make a great enclosure for something like a Bluetooth speaker? That seems to be exactly what happened to [Penguin DIY].

In the mesmerizing video after the break, you’ll see [Penguin DIY] do what seems to be impossible. They start with a tiny 5 V power bank module which is still not small enough to fit, so they remove all the components and dead-bug them back together.

This is really just the beginning. There of course has to be a female USB of some type, so [Penguin DIY] Dremels out the perfect little slot for it.

They did manage to stack and fit a MH-MH18 Bluetooth audio module and an HXJ8002 mini audio amplifier module in the walnut, but of course, it took a lot of fiddly wiring to extend the LEDs and wire them up.

Then in the other half of the shell went the 4Ω 2 W mini speaker. [Penguin DIY] of course drilled a ton of little holes in the shell for the sound to come through. Also on this side are three tiny switches for play/pause and previous and next track, and the latter two can be long pressed to control the volume. Definitely check this out after the break.

Do the notifications of your Bluetooth speaker annoy you? There’s a hack for that.

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Homebrew TEM Cell Lets You EMC Test Your Own Devices

November 2, 2023 by 14 Comments

Submitting a new device for electromagnetic compatibility (EMC) testing seems a little like showing up for the final exam after skipping all the lectures. You might get lucky and pass, but it really would have been smarter to take a few of the quizzes to see how things were going during the semester. Similarly, it would be nice to know you’re not making any boneheaded mistakes early in the design process, which is what this DIY TEM cell is all about.

We really like [Petteri Aimonen]’s explanation of what a TEM cell, or transverse electromagnetic cell, is: he describes it as “an expanded coaxial cable that is wide enough to put your device inside of.” It basically a cage made of conductive material that encloses a space for the device under test, along with a stripline going down its center. The outer cage is attached to the outer braid of a coaxial cable, while the stripline is connected to the center conductor. Any electric or magnetic field generated by the device inside the cage goes down the coax into your test instrument, typically a spectrum analyzer.

[Petteri]’s homebrew TEM is made from a common enough material: copper-clad FR4. You could use double-sided material, or even sheet copper if you’re rich, but PCB stock is easy to work with and gets the job done. His design is detailed in a second post, which goes through the process of designing the size and shapes of all the parts as well as CNC milling the sheets of material. [Petteri] tried to make the joints by milling part-way through the substrate and bending the sheet into shape, but sadly, the copper didn’t want to cooperate with his PCB origami. Luckily, copper foil tape and a little solder heal all wounds. He also incorporated a line impedance stabilization network (LISN) into the build to provide a consistent 50-ohm characteristic impedance.

How does it work? Pretty well, it seems; when connected to a TinySA spectrum analyzer, [Petteri] was able to find high-frequency conductive noise coming from the flyback section of a switch-mode power supply. All it took was a ferrite bead and cap to fix it early in the prototyping phase of the project. Sounds like a win to us.

A Network Adapter Thinks It’s A CD-ROM. Restore Its True Calling!

November 2, 2023 by 32 Comments

A mildly annoying trend over recent years has been for USB hardware devices to expose a CD-ROM drive containing their drivers for Windows users. Of course there’s no real CD in there, instead the software lives on a piece of flash memory. It’s usually not a problem as they also appear on the USB bus as their true calling, but not always.

[Martijn Braam] found himself the lucky owner of a USB network adapter which seemed to see its only purpose in life to be such a drive, and since he  wasn’t anxious to make another piece of e-waste, he broke it open to see if the fake CD drive could be disabled.

Inside the flimsy case he found a CoreChips SR9700 Ethernet controller, a chip for which there seems to be very little data in the wild. On the underside of the PCB was a flash chip, and as expected disabling this caused the CD drive to disappear to be replaced by the expected network card.

It’s a simple but useful hack, but there’s a little bonus for those unaware in the write-up. There’s a piece of software called USB_modeswitch that can perform this task on many cards, which is worth storing away in the event that it’s needed.

Toy Gaming Controller Makes The Big Leagues

November 1, 2023 by 5 Comments

Some of the off-brand video game consoles and even accessories for the major brands can leave a lot to be desired. Whether it’s poor build quality or a general lack of support or updates, there are quite a few things on the market not worth anyone’s time or money. [Jonathan] was recently handed just such a peripheral, a toy game controller originally meant for a small child, but upon further inspection it turned into a surprisingly hackable platform, capable of plenty of IoT-type tasks.

The controller itself was easily disassembled, and the functional buttons within were wired to a Wemos D1 Mini instead of the originally-planned ESP32 because of some wiring irregularities and the fact that the Wemos D1 Mini having the required amount of I/O. It’s still small enough to be sealed back inside the controller as well, powered by the batteries that would have powered the original controller.

For the software, [Jonathan] is using MQTT to register button presses with everything easily accessible over Wi-Fi, also making it possible to update the software wirelessly. He was able to use it to do a few things as proof-of-concept, including playing a game in PyGame and controlling a Sonos speaker, but for now he’s using it to control an LED sculpture. With something this easily modified, though, it would be pretty straightforward to use it instead for a home automation remote control, especially since it is already set up to use MQTT.

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Raspberry Pi OS In-Place Upgrades, Not For The Faint Hearted

November 1, 2023 by 33 Comments

The Raspberry Pi series of boards are noted for their good software support, with a continuous flow of operating system upgrades such that an original Pi from 2012 will still boot the latest Pi OS. But these upgrades are best done by writing a fresh SD card, so oddly, the Pi remains surprisingly difficult in many cases to upgrade in place. [Iustin Pop] has taken a look at the problem, and finds that though it’s not always easy it remains possible with a bit or work.

An upgrade in place of a Raspberry Pi OS install that’s running on a headless device is probably the simplest of the lot, with a relatively small set of issues. Do it on a machine using the GUI though, and the switch from x.org to Wayland makes for a whole world of pain.

Perhaps most interesting for the insight it gives us into the way Raspberry Pi OS is derived from Debian, is the crossgrade process from the ARMhf build for earlier machines to the ARM64 one for the more recent ones. Here aside from a headache of differing paths and versions, he encounters the Pi-specific compilation tweaks put in place by the developers of Raspberry Pi OS, leading to the ARMhf version being a different branch from the original Debian than the ARM64 one.

Having read his examination of in-place upgrades we have to say that simply writing a new SD card remains the most attractive option. But sometimes along comes a remote system where that’s simply not possible, and this guide might just be very useful sometime.

2023 Halloween Hackfest: Spooky Noise Maker Is Self-Contained

November 1, 2023 by 4 Comments

We just love it when y’all build off of each other’s projects. This spooky Halloween noise maker from [C.M. Herron] is no exception. But while the projects we’ve seen lately rely on external computers and/or guitar pedals to create the effects part of the build, this one has everything running on a Raspberry Pi that sits inside the box.

Readers of a certain vintage will recognize this as an 8-track storage box, on top of which are several noise-making objects that creak and ting and reverberate nicely. A USB microphone picks up the sounds, and by using a regular microphone instead of a piezo, [C.M.] can introduce varying levels of feedback to make the sounds even spookier.

So, how did [C.M.] make this work on a Pi 4? To put it simply, they’ve got the Reaper DAW and Windows Valhalla plugins running on top of WINE, which running on top of Box64, which is running on top of the Bullseye Pi OS. [C.M.] sure learned a lot from this build, and hopes to inspire others to build their own spooky noise boxen. Plus, they’ve already thought of ways to improve it for next year. Be sure to check it out in action after the break.

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This OSHW Trackball Is Ready To Be Customized

November 1, 2023 by 25 Comments

Oh sure, Amazon can deliver any number of Logitech peripherals to your door in 48 hours, but where’s the fun in that? With open source hardware (OSHW) input devices like the Ploopy Adept Trackball, you not only get to say you built the thing yourself, but there’s also an opportunity to tune the gadget to your exacting specifications — even if that just means packing it full of RGB LEDs.

The trackball is powered by the Raspberry Pi Pico running QMK, features a high-accuracy PMW3360 sensor that can be found in commercial gaming mice, and uses a snooker ball for the business end. All the hardware is wrapped up in a 3D printed enclosure, and thanks to the VIA project, configuring the device can be done right in the browser through a web app.

Like the other devices in the (somewhat unfortunately named) Ploopy family, all of the design files for the Adept Trackball are released under the CERN license, which combined with the project’s fantastic documentation means you’ve got everything you need to build it from scratch. There are official parts kits if you don’t want to source or print all the components yourself, but as of this writing, the Ploopy Shop will only let you preorder them.