Hacking Together An Expensive-Sounding Microphone At Home

When it comes to microphones, [Roan] has expensive tastes. He fancies the famous Telefunken U-47, but doesn’t quite have the five-figure budget to afford a real one. Thus, he set about getting as close as he possibly could with a build of his own.

[Roan] was inspired by [Jim Lill], who is notable for demonstrating that the capsule used in a mic has probably the greatest effect on its sound overall compared to trivialities like the housing or the grille. Thus, [Roan’s] build is based around a 3U Audio M7 capsule. It’s a large diaphragm condenser capsule that is well regarded for its beautiful sound, and can be had for just a few hundred dollars. [Roan] then purchased a big metal lookalike mic housing that would hold the capsule and all the necessary electronics to make it work. The electronics itself would be harvested from an old ADK microphone, with some challenges faced due to its sturdy construction. When the tube-based amplifier circuit was zip-tied into its new housing along with the fancy mic capsule, everything worked! Things worked even better when [Roan] realized an error in wiring and got the backplate voltage going where it was supposed to go. Some further tweaks to the tube and capacitors further helped dial in the sound.

If you’ve got an old mic you can scrap for parts and a new capsule you’re dying to use, you might pursue a build like [Roan’s]. Or, you could go wilder and try building your own ribbon mic with a gum wrapper. Video after the break.

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100-Year Old Wagon Wheel Becomes Dynamometer

If you want to dyno test your tuner car, you can probably find a couple of good facilities in any  nearby major city. If you want to do similar testing at a smaller scale, though, you might find it’s easier to build your own rig, like [Lou] did.

[Lou’s] dynamometer is every bit a DIY project, relying on a 100-year-old wagon wheel as the flywheel installed in a simple frame cobbled together from 6×6 timber beams. As you might imagine, a rusty old wagon wheel probably wouldn’t be in great condition, and that was entirely true here. [Lou] put in the work to balance it up with some added weights, before measuring its inertia with a simple falling weight test. The wheel is driven via a chain with a 7:1 gear reduction to avoid spinning it too quickly. Logging the data is a unit from BlackBoxDyno, which uses hall effect sensors to measure engine RPM and flywheel RPM. With this data and a simple calibration, it’s possible to calculate the torque and horsepower of a small engine hooked up to the flywheel.

Few of us are bench testing our lawnmowers for the ultimate performance, but if you are, a build like this could really come in handy. We’ve seen other dyno builds before, too. Video after the break.

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Avoid Missed Connections With The Connectorbook’s Web Tool

Connectors are wonderful and terrible things. Wonderful, in that splicing wires every time you need to disassemble something is really, really annoying. Terrible in that it can be just such an incredible pain-in-the-assets to find the right one if you’re stuck with just a male or a female for some unfortunate reason. We’ve all been there, and all spent time growing increasingly frustrated poring over the DigiKey catalog (or its local equivalent) trying to figure out what the heck we were dealing with. That’s why [Davide Andrea]’s The Connectorbook exists–and even better, the free web service they call Identiconn.

The tool isn’t super new–the Wayback Machine has snapshots of it dating back to 2021–but it’s still very much worth highlighting. There’s a “quick pick” option that lets you narrow it down with photos, or if you want to get specific there are dozens of filters to try and help you find your exact part. You can filter based on everything from the pitch and geometry of the connectors, to how it terminates, attachments, latches, et cetera. While we can’t guarantee the database is fully exhaustive, it looks pretty darn big, and using it is going to be a lot less exhausting than pouring through catalogs hoping that particular vendor or manufacturer lists the matching part.

Some might argue that this database is not a hack, but it’s certainly going to enable a certain amount of hacking. That’s why we’re grateful to [Alex] for the tip! If you’ve got a know tool you think we all should know about that hasn’t been shared yet, please let us know.

What Happened To Running What You Wanted On Your Own Machine?

When the microcomputer first landed in homes some forty years ago, it came with a simple freedom—you could run whatever software you could get your hands on. Floppy disk from a friend? Pop it in. Shareware demo downloaded from a BBS? Go ahead! Dodgy code you wrote yourself at 2 AM? Absolutely. The computer you bought was yours. It would run whatever you told it to run, and ask no questions.

Today, that freedom is dying. What’s worse, is it’s happening so gradually that most people haven’t noticed we’re already halfway into the coffin.

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Open Source Hack Lets The Razer Nari Headset Work With Linux

The Razer Nari is a decent wireless headset, but it’s a little oddball—because it uses a bespoke USB dongle for pairing. This is all well and good if you’re using a supported configuration; plug it into a Windows PC, run the utility, and you’re good to go. If you’re a Linux user, though, you were out of luck—but [JJ] has just solved that problem.

The tool was created by reverse engineering the pairing protocol used by Razer’s own proprietary software. [JJ] figured out the necessary pairing command, and how to send it to both the dongle and the headset. The headset itself must be connected by a USB cable when initiating the pairing process.

[JJ] believes the tool should work with any Razer Nari and dongle variant. However, the Nari Ultimate and Nari Essential models are yet to be tested, with verification still required. However, the pairing commands were extracted from Razer’s own tool and don’t appear to differ so it should probably work across the boardSetup is still a little fussy, particularly to get both the Game Audio and Chat Audio outputs working under Linux. However, [JJ] has helpfully provided the necessary detail to get everything up and running with PulseAudio and PipeWire setups.

Proprietary hardware can be frustrating to work with at times, but that’s never stopped hackers from reverse engineering their way to success before. If you’ve got your own projects in this vein, don’t hesitate to notify the tipsline!

Blinking An LED With A Single Transistor

Let’s say you want to blink an LED. You might grab an Arduino and run the Blink sketch, or you might lace up a few components to a 555. But you needn’t go so fancy! [The Design Graveyard] explains how this same effect can be achieved with a single transistor.

The circuit in question is rather odd at first blush. The BC547 NPN transistor is hooked up between an LED and a resistor leading to a 12V DC line, with a capacitor across the emitter and collector. Meanwhile, the base is connected to… nothing! It’s just free-floating in the universe of its own accord. You might expect this circuit to do nothing at all, but if you power it up, the LED will actually start to flash.

The mechanism at play is relatively simple. The capacitor charges to 12 volts via the resistor. At this point, the transistor, which is effectively just acting as a poor diode in this case, undergoes avalanche breakdown at about 8.5 to 9 volts, and starts conducting. This causes the capacitor to discharge via the LED, until the voltage gets low enough that the transistor stops conducting once again. Then, the capacitor begins to charge back up, and the cycle begins again.

It’s a weird way to flash an LED, and it’s not really the normal way to use a transistor—you’re very much running it out of spec. Regardless, it does work for a time! We’ve looked at similar circuits before too. Video after the break.

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Classy Desk Simulates Beehive Activity

Beehives are impressive structures, an example of the epic building feats that are achievable by nature’s smaller creatures. [Full Stack Woodworking] was recently building a new work desk, and decided to make this piece of furniture a glowing tribute to the glorious engineering of the bee. (Video, embedded below.)

The piece is a conventional L-shaped desk, but with a honeycomb motif inlaid into the surface itself. [Full Stack Woodworking] started by iterating on various designs with stacked hexagons made out of laser cut plywood and Perspex, filled with epoxy. Producing enough hexagons to populate the entire desk was no mean feat, requiring a great deal of cutting, staining, and gluing—and all this before the electronics even got involved! Naturally, each cell has a custom built PCB covered in addressable LEDs, and they’re linked with smaller linear PCBs which create “paths” for bees to move between cells.

What’s cool about the display is that it’s not just running some random RGB animations. Instead, the desk has a Raspberry Pi 5 dedicated to running a beehive simulation, where algorithmic rules determine the status (and thus color) of each hexagonal cell based on the behavior of virtual bees loading the cells with honey. It creates an organic, changing display in a way that’s rather reminiscent of Conway’s Game of Life.

It was a huge build, but the final result is impressive. We’ve featured some other great custom desks over the years too. Video after the break.

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