Messing With A Cassette Player Never Sounded So Good

April 24, 2023 by 8 Comments

Cassette players and tapes are fertile hacking ground. One reason is that their electromechanical and analog nature provides easy ways to fiddle with their operation. For example, slow down the motor and the playback speed changes accordingly. As long as the head is moving across the tape, sound will be produced. The hacking opportunities are nicely demonstrated by [Lara Grant]’s cassette player mod project.

The device piggybacks onto a battery-powered audio cassette player and provides a variety of ways to fiddle with the output, including adjustable echo and delay, and speed control. At the heart of the delay and echo functionality is the PT2399, a part from the late 90s capable of some pretty impressive audio effects (as long as a supporting network of resistors and capacitors are in place, anyway.)

[Lara] provides a schematic for the PT2399’s interface to the cassette player’s output, which is handy should anyone want to try a similar modification. Speed of playback is controlled by adjusting the cassette player’s motor with PWM. Volume control swaps a photocell in place of a rotary volume potentiometer, and additional audio jacks provide flexibility for mixing and matching input and output with other equipment.

You can see it in action in the video embedded below. Intrigued, and want a few more examples of modified tape players? How about a strange sort of cassette synth, or this unique take on a mellotron that uses a whopping 14 modified tape players under the hood? And really out there is the Magnetotron, which consists of a large rotating cylinder with tape loops stuck to it — the magnetic read head is mounted on a wand which the user manually moves across the tapes to create sounds.

Tape players are accessible, hackable things, so remember to drop us a line if you make something neat!

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Op Amp Contest: Go Down An Octave, No FFT, No PLL, No Oscillator!

April 24, 2023 by 16 Comments

We like a project that makes us think, and that was certainly the case with [MS-BOSS]’s octave downshifter that’s an entry in our current op-amp contest. Instead of resorting to an FFT, or a PLL, it uses a technique best described as a custom analogue computer to implement the maths of octave downshifting. It’s an extremely clever approach, and we don’t mind admitting took us more than one read to understand how it works.

Just as you would with any mathematical problem, he’s split the job of halving the frequency into its constituent mathematical functions. The square root calculation circuit is probably the one that most required the dredging up of dimly-remembered analogue circuitry undergraduate courses for us.

The result is a fascinating read that’s well worth taking the time to understand if you have any interest in analogue electronics. It’s by no means the easiest way to make this particular effect in 2023, as we’re much more used to seeing our community make digital effects, but if you fancy yourself as any kind of op-amp designer, you really need to give it a look.

2023 Hackaday.io Op Amp Challenge

Warmer Ice Cream?

April 24, 2023 by 53 Comments

What if you could tweak the recipe on ice cream to keep it frozen at higher temperatures? The idea comes from massive conglomerate Unilever. Among other things, the brand owns a wide variety of ice cream brands, from Ben & Jerry’s to the Magnum and Cornetto lines. Instead of running freezers at the industry standard of -18 °C (0°F), the company is experimenting with upping the temperature to -12 °C (10 °F) instead.

First off, you’d save a lot of electricity. Thanks to the way the industry works, the company actually owns the vast majority of the three million or so display freezers that are used to sell its stock to customers. Running at a higher temperature could slash the freezer’s energy use by 20% to 30%, according to the company’s calculations. The company also estimates that the energy used by these freezers makes up around 10% of its total greenhouse gas footprint, so it’s better for the environment too.

Of course, there’s savvy commercial reasons behind the idea. Unilever had noticed its ice cream sales dropping in 2022. The company believes this was in part due to retailers unplugging their freezers earlier than usual as winter approached, due to high energy bills. If the company’s freezers aren’t humming, they’re doing less business. If shaving down the freezer’s energy use helps retailers keep them plugged in and the lights on, that’s a net bonus to the company’s bottom line. It could also make their freezers unhospitable places for rival products, giving them an edge in the marketplace.

But this is all business intrigue. Let’s instead take a deeper look at ice cream.

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Chatting With Local AI Moves Directly In-Browser, Thanks To Web LLM

April 24, 2023 by 7 Comments

Large Language Models (LLM) are at the heart of natural-language AI tools like ChatGPT, and Web LLM shows it is now possible to run an LLM directly in a browser. Just to be clear, this is not a browser front end talking via API to some server-side application. This is a client-side LLM running entirely in the browser.

The ability to run an LLM (natural language AI) directly in-browser means more ways to implement local AI while enjoying GPU acceleration via WebGPU.

Running an AI system like an LLM locally usually leverages the computational abilities of a graphics card (GPU) to accelerate performance. This is true when running an image-generating AI system like Stable Diffusion, and it’s also true when implementing a local copy of an LLM like Vicuna (which happens to be the model implemented by Web LLM.) The thing that made Web LLM possible is WebGPU, whose release we covered just last month.

WebGPU provides a way for an in-browser application to talk to a local GPU directly, and it sure didn’t take long for someone to get the idea of using that to get a local LLM to run entirely within the browser, complete with GPU acceleration. This approach isn’t just limited to language models, either. The same method has been applied to successfully create Web Stable Diffusion as well.

It’s a fascinating (and fast) development that opens up new possibilities and, hopefully, gives people some new ideas. Check out Web LLM’s GitHub repository for a closer look, as well as access to an online demo.

The BSides: More Curious Uses Of Off-the-shelf Parts

April 24, 2023 by 10 Comments

Off-the-shelf stock parts are the blocks from which we build mechanical projects. And while plenty of parts have dedicated uses, I enjoy reusing them in ways that challenge what they were originally meant for while respecting the constraints of their construction. Building off of my piece from last time, I’d like to add to your mechanical hacking palette with four more ways we can re-use some familiar off-the-shelf parts. Continue reading “The BSides: More Curious Uses Of Off-the-shelf Parts” →

3D Scanning A Room With A Steam Deck And A Kinect

April 24, 2023 by 2 Comments

It may not be obvious, but Valve’s Steam Deck is capable of being more than just a games console. Demonstrating this is [Parker Reed]’s experiment in 3D scanning his kitchen with a Kinect and Steam Deck combo, and viewing the resulting mesh on the Steam Deck.

The two pieces of hardware end up needing a lot of adapters and cables.

[Parker] runs the RTAB-Map software package on his Steam Deck, which captures a point cloud and color images while he pans the Kinect around. After that, the Kinect’s job is done and he can convert the data to a mesh textured with the color images. RTAB-Map is typically used in robotic applications, but we’ve seen it power completely self-contained DIY 3D scanners.

While logically straightforward, the process does require some finessing and fiddling to get it up and running. Reliability is a bit iffy thanks to the mess of cables and adapters required to get everything hooked up, but it does work. [Parker] shows off the whole touchy process, but you can skip a little past the five minute mark if you just want to see the scanning in action.

The Steam Deck has actual computer chops beneath its games console presentation, and we’ve seen a Steam Deck appear as a USB printer that saves received print jobs as PDFs, and one has even made an appearance in radio signal direction finding.

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OSI Superboard II Replicated

April 24, 2023 by 6 Comments

While our modern computer can easily emulate a lot of different old machines, there is something about having replica hardware that is even better. Not as nice as having the real thing, in some ways, although you don’t have to worry about wear and tear on a replica, either. [Jeff Tranter] has built a kit replica of an Ohio Scientific Superboard II, and it looks great, as you can see in the video below.

This was an inexpensive all-in-one 6502 computer with a keyboard and provision for TV or monitor output. If you had a 5V power supply, a cassette deck, and a TV you were in business for less money than most of the comparable alternatives. In fact, [Jeff] has the canceled check where his parents paid $486 Canadian for one in 1981. That was his introduction to computing, and we’d say that was a reasonable investment on the part of his parents.

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