You Can Make Your Own Ribbon Mic With A Gum Wrapper

May 29, 2025 by Lewin Day 13 Comments

There are lots of different types of microphone, with the ribbon microphone being one of the rarer ones. Commercial versions are often prized for their tone and frequency response. You can make your own too, as [Something Physical] demonstrates using a packet of chewing gum.

Yes, the ribbon in this microphone was literally gained from Airwaves Extreme gum. It’s got nothing to do with freshness or the special mintiness quotient of the material, though; just that it’s a conductive foil and it makes the YouTube video more interesting to watch.

The gum wrapper is first soaked in hot water and then acetone, such that the paper backing can be removed. The foil is then corrugated with a tube press with some baking paper used for protection during this delicate process. The “motor” of the ribbon microphone is then produced out of plexiglass, copper tape, and a pair of powerful magnets. The ribbon is then stretched between the magnets and clamped in place, acting as the part of the microphone that will actually vibrate in response to sound. As it vibrates in the magnetic field, a current is generated in response to the sound. From there, it’s just a matter of hooking up a custom-wound transformer to the wires leading to the “motor” and it’s ready to test. It works off the bat, but there is some noise. Adding shielding over the transformer and a proper enclosure helps to make the microphone more fit for purpose.

If you’ve ever wanted to experiment with microphone construction, it’s hard to go past the joy of building a simple ribbon mic. You can experiment at will with different sizes and materials, too; you needn’t just limit yourself to different brands of gum!

We’ve featured some other great mic builds over the years, too. Video after the break.

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Researchers Are Slowly Finding Ways To Stem The Tide Of PFAS Contamination

May 29, 2025 by Lewin Day 67 Comments

If you’ve been following environmental news over the past couple of decades, you’ve probably heard about PFAS – those pesky “forever chemicals” that seem to turn up everywhere from drinking water to polar bear blood. They’re bad for us, and we know it, but they’ve been leeching into the environment for decades, often as a result of military or industrial activity. What’s worse is that these contaminants just don’t seem to break down—they stick around in the environment causing harm on an ongoing basis.

Now, researchers are finally cracking the code on how to deal with these notoriously stubborn molecules. It won’t be easy, but there’s finally some hope in the fight against the bad stuff that doesn’t just wash away.
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Supercon 2024: Using An Oscilloscope To Peek Below The Noise Floor

May 28, 2025 by Lewin Day 7 Comments

When you’re hunting for a signal with your oscilloscope, the stronger it is, the better. If it’s weak, you might struggle to tease it out from other interference, or even from the noise floor itself. You might wish that you were looking for something more obvious rather than the electromagnetic equivalent of a needle in a haystack.

Finding hidden signals below the noise floor may be a challenge, but it needn’t be an insurmountable one. James Rowley and Mark Omo came to the 2024 Hackaday Superconference to tell us how to achieve this with the magic of lock-in amplifiers.

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The Commodore 64 Gets An HDMI Upgrade

May 25, 2025 by Lewin Day 39 Comments

The Commodore 64 may remain the best selling computer of all time, but it has one major flaw. It doesn’t have HDMI! That makes it a total pain to use with modern displays. Thankfully, [Side Projects Lab] has whipped up an HDMI output board to solve this concerning oversight from the original designers.

The project was inspired by work by [Copper Dragon], who whipped up a nifty RGB output board. This device worked by reading the inputs to the C64’s VIC II graphics chip, which it then used to recreate a pixel-perfect video frames to then produce a quality analog video output. [Side Projects Lab] figured the same interception technique would be useful for producing a quality HDMI output.

The result was the HD-64. It sits inside the C64 in place of the original RF modulator. It uses an interleaver socket to capture digital signals going to the VIC II. It then feeds these signals to an emulated VIC II running inside an FPGA, which creates the pixel-perfect screen representation and synthesizes the proper digital HDMI output. Meanwhile, the analog audio output from the SID chip is captured from the RF modulator’s original header, and sent out via the HDMI output as well. The default output is super-sharp, but the device can be configured to allow scanlines and anti-aliasing if that’s more to your tastes.

If you want to hook your C64 up to a modern screen, this is going to be one of the tidiest and sharpest ways to do it. We’ve seen similar hacks for other platforms before, too. Video after the break.

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Nerf Blaster Becomes Remote Control Turret

May 24, 2025 by Lewin Day 5 Comments

For most of us, turrets that aim and shoot at things are the sole domain of video games. However, they’re remarkably easy to build with modern technology, as [meub] demonstrates. Meet the SwarmTurret.

The build is based around an existing foam blaster, namely the Nerf Swarmfire. This blaster was chosen for being easy to integrate into the build, thanks to its motorized direct-plunger firing mechanism and electronic trigger. It also has the benefit of being far less noisy and quicker to fire than most flywheel blasters.

For this build, the Nerf blaster was slimmed down and fitted to a turret base built with hobby servos and 3D printed components. The blaster is also fitted with a webcam for remote viewing. A Raspberry Pi is running the show, serving up a video feed and allowing aiming commands to be sent via a Websockets-based interface. Thus, you can login via a web browser on your phone or laptop, and fire away at targets to your heart’s content.

We’ve featured some great turrets before, like this Portal-themed unit.

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LED Matrix Built For M.2 Interface

May 24, 2025 by Lewin Day 8 Comments

The M.2 slot is usually used for solid-state storage devices. However, [bitluni] had another fun idea for how to use the interface. He built an M.2 compatible LED matrix that adds a little light to your motherboard.

[bitluni] built a web tool for sending images to the matrix.

[bitluni] noted that the M.2 interface is remarkably flexible, able to offer everything from SATA connections to USB, PCI Express, and more. For this project, he elected to rely on PCI Express communication, using a WCH CH382 chip to translate from that interface to regular old serial communication.

He then hooked up the serial interface to a CH32V208 microcontroller, which was tasked with driving a 12×20 monochrome LED matrix. Even better, he was even able to set the microcontroller up to make it programmable upon first plugging it into a machine, thanks to its bootloader supporting serial programming out of the box. Some teething issues required rework and modification, but soon enough, [bitluni] had the LEDs blinking with the best of them. He then built a web-based drawing tool that could send artwork over serial direct to the matrix.

While most of us are using our M.2 slots for more traditional devices, it’s neat to see this build leverage them for another use. We could imagine displays like this becoming a neat little add-on to a blingy computer build for those with a slot or two to spare. Meanwhile, if you want to learn more about M.2, we’ve dived into the topic before.

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EMF Forming Was A Neat Aerospace Breakthrough

May 23, 2025 by Lewin Day 9 Comments

Typically, when we think about forming metal parts, we think about beating them with hammers, or squeezing them with big hydraulic presses. But what if magnets could do the squeezing? As it turns out—Grumman Aerospace discovered they can, several decades ago! Even better, they summed up this technique in a great educational video which we’ve placed below the break.

The video concerns the development of the Grumman EMF Torque Tube. The parts are essentially tubes with gear-like fittings mounted in either end, which are fixed with electromagnetic forming techniques instead of riveting or crimping. Right away, we’re told the key benefits—torque tubes built this way are “stronger, lighter, and more fatigue resistant” than those built with conventional techniques. Grumman used these torque tubes in such famous aircraft as the F-14 Tomcat, highlighting their performance and reliability.

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