A man's hand is shown holding a 3D-printed structure. The structure is hollow and has a fiber-optic cable leading to it. Blue light shines from a hole in the structure. In the background, a laser module is coupled to a fiber-optic cable.

Building A Laser-Driven Photoacoustic Speaker

March 22, 2026 by 6 Comments

An MRI scan is never a pleasant occasion – even if you aren’t worried about the outcome, lying still in a confined, noisy space for long periods of time is at best an irksome experience. For hearing protection and to ameliorate boredom or claustrophobia, the patient wears headphones. Since magnets and wires can’t be used inside an MRI machine, the headphones have to literally pipe the sound in through tubes, which gives them poor sound quality and reduces the amount of noise they can block. [SomethingAboutScience], however, thinks that photoacoustic speakers could improve on these, and built some to demonstrate.

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The 3DFX Voodoo Lives Again In An FPGA

March 22, 2026 by 34 Comments

The 3DFX Voodoo was not the first dedicated 3D graphics chipset by any means, but it became the favourite for gamers among the early mass-market GPUs. It would be found on a 3D-processing-only PCI card that sat on the feature connector of your SVGA card. The Voodoo took any game that supported its Glide API into the world of (for the time) smooth and beautiful 3D. They’re worth a bit now, but if you don’t fancy forking out for mid-’90s silicon in 2026, there’s another option. [Francisco Ayala Le Brun] has implemented the 3DFX Voodoo 1 in SpinalHDL for FPGAs.

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Hackaday Links: March 22, 2026

March 22, 2026 by 1 Comment

On Friday, Reuters reported that Amazon is going to try to get into the smartphone game…again. The Fire Phone was perhaps Amazon’s biggest commercial misstep, and was only on the market for about a year before it was discontinued in the summer of 2015. But now industry sources are saying that a new phone code-named “Transformer” is in the works from the e-commerce giant.

At this point, there’s no word on how much the phone would cost or when it would hit the market. The only information Reuters was able to squeeze out of their contacts was that the device would feature AI heavily. Real shocker there — anyone with an Echo device in their kitchen could tell you that Amazon is desperate to get you talking to their gadgets, presumably so they can convince you to buy something. While a smartphone with even more AI features we didn’t ask for certainly won’t be on our Wish List, if history is any indicator, we might be able to pick these things up cheap on the second-hand market.

On the subject of AI screwing everything up, earlier this week, the Electronic Frontier Foundation reported that The New York Times had started blocking the Internet Archive’s crawlers, citing concerns over their content being scraped up by bots for training data. The EFF likens this to a newspaper asking libraries to stop storing copies of their old editions, and warns that in an era where most people get their news via the Internet, not having an archived copy of sites like The Times will put holes in the digital record. They also point out that mirroring web pages for the purposes of making them more easily searchable is a widely accepted practice (ask Google) and has been legally recognized as fair use in court.

Assuming we take the NYT’s side of the story at face value, there’s a tiny part of our cold robotic heart that feels some sympathy for them. Over the last year or so, we’ve noticed some suspicious activity that we believe to be bots siphoning up content from the blog and Hackaday.io, and it’s resulted in a few technical headaches for us. On the other hand, what’s Hackaday here for if not to share information? Surely the same could be said for any newspaper, be it the local rag or The New York Times. If a chatbot learning some new phrases from us is the cost of doing business in 2026, so be it. Can’t stop the signal.

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Figure 1 from the paper: the apparatus and a disintegration fingerprint.

IDing Counterfeit Drugs Might Be Easier Than You Think

March 22, 2026 by 34 Comments

Odds are, you’ve taken pills before; it’s a statistical certainty that some of you reading this took several this morning. Whenever you do, you’re at the mercy of the manufacturer: you’re trusting that they’ve put in the specific active ingredients in the dosage listed on the package. Alas, given the world we live in, that doesn’t always happen. Double-checking actual concentrations requires expensive lab equipment like gas chromatography. It turns out checking for counterfeit pills is easier than you’d think, thanks to a technique called Disintegration Fingerprinting.

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Storing Solar Energy As Ice For Air Conditioning

March 22, 2026 by 79 Comments

Thermal energy storage is pretty great, as phase-change energy storage is very consistent with its energy output over time, unlike chemical batteries. You also get your pick from a wide range of materials that you can either heat up or cool down to store energy. Here, the selection is mostly dependent on how you wish to use that energy at a later date. [Hyperspace Pirate] is mostly interested in cooling down a house, on account of living in Florida.

As can be seen in the top image, the basic setup is pretty straightforward. PV solar power charges a battery until it’s fully charged. Then an MCU triggers a relay on the AC inverter, which then starts the cooling compressor on the water reservoir. This proceeds to phase change the water from a liquid into ice. The process can later be reversed, which will draw thermal energy out of the surrounding air and thus provide cooling.

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Arduino Code? On My 8051? It’s More Likely Than You Think

March 22, 2026 by 27 Comments

The 8051 was an 8-bit Harvard-architecture microcontroller first put out by Intel in 1980.  They’ve since discontinued that line, but it lives on in the low-cost STC8 family of chips, which is especially popular in Asia. They’re cheap as, well, chips — under 1$ — but lack compatibility with modern toolchains. If you’re happy with C, then you’re fine, but if you want to plus-plus it up and use all those handy-dandy shortcuts provided by the Arduino ecosystem, you’re out of luck. Or rather, you were, until [Bùi Trịnh Thế Viên] aka [thevien257] came up with a workaround.

The workaround is delightfully Hack-y. One could, conceivably, port a compiler for Arduino’s  Wiring to the 8051, but that’s not what [Viên] did, probably because that would be a lot of work. There isn’t even a truly modern toolchain to put plain C on this chip. Instead, [Viên] started with rv51, a RISC-V emulator written in 8051 assembly language by [cryozap]. RISC-V is a lot easier to work with and, frankly, a more useful skill to build up.

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An oscilloscope display is seen in lower left corner. In the rest of the image, two purple circuit boards are connected by SMA RF cables. A wire antenna is connected to one board.

Building A $50 SDR With 20 MHz Bandwidth

March 22, 2026 by 9 Comments

Although the RTL-SDR is cheap, accessible, and capable enough for many projects, it does have some important limitations. In particular, its bandwidth is limited to about 3.2 MHz, and the price of SDRs tends to scale rapidly with bandwidth. [Anders Nielsen], however, is building a modular SDR with a target price of $50 USD, and has already reached a bandwidth of almost 20 MHz.

If this project looks familiar, it’s because we’ve covered an earlier iteration. At the time, [Anders] had built the PhaseLoom, which filters an incoming signal, mixes it down to baseband, and converts it to I/Q signals. The next stage is the PhaseLatch, a board housing a 20-MHz, 10-bit ADC, which samples the in-phase and quadrature signals and passes them on to a Cypress FX2LP microcontroller development board. [Anders] had previously connected the ADC to a 6502 microprocessor instead of the FX2LP, but this makes it a practical SDR. The FX2LP was a particularly good choice for this project because of its USB 2.0 interface, large buffers for streaming data, and parallel interface. It simply reads the data from the SDR and dumps it to the computer.

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