10 Cent Microcontroller Makes Music

October 23, 2025 by 11 Comments

Compared to the old 8-bit Arduinos, it’s incredible how cheap modern microcontrollers like the ESP32 have become. But there are even cheaper options out there if you don’t need that kind of horsepower, and are willing to do a little work yourself, as [atomic14] demonstrates.

The CH32V003 is a dirt cheap microcontroller—which can reportedly be had for as little as 10 cents if you know where to look. It’s not the most powerful chip by any means, boasting just 16 K flash, and 2 K of SRAM. However, it is a 32-bit RISC V machine, and it does run at 48 MHz—giving it a leg up on many 8-bit parts that are still out there.

Surprisingly there aren’t a whole lot of CH32V003 products for the maker market, so if you want to play with it, you’ll probably need to spin up your own boards. [atomic14] does just that, showing us how the chip can be put to good use by turning it into a little musical trinket. It’s a fun demo, and a great way to get to grips with programming on a new microcontroller platform.

It’s hard to get more chiptune than a 10 cent chip beeping its little head off. How could possibly justify spending tens of dollars modding a Game Boy when this exists, even if it sounds like a caffeinated greeting card?

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Built-In Batteries: A Daft Idea With An Uncertain Future

October 23, 2025 by 58 Comments

Having a gadget’s battery nestled snugly within the bowels of a device has certain advantages. It finally solves the ‘no batteries included’ problem, and there is no more juggling of AA or AAA cells, nor their respective chargers. Instead each device is paired to that one battery that is happily charged using a standardized USB connector, and suddenly everything is well in the world.

Everything, except for the devices that cannot be used while charging, wireless devices that are suddenly dragging along a wire while charging and which may have charging ports in irrational locations, as well as devices that would work quite well if it wasn’t for that snugly embedded battery that’s now dead, dying, or on fire.

Marrying devices with batteries in this manner effectively means tallying up all the disadvantages of the battery chemistries and their chargers, adding them to the device’s feature list, and limiting their effective lifespan in the process. It also prevents the rapid swapping with fresh batteries, which is why everyone is now lugging chunky powerbanks around instead of spare batteries, and hogging outlets with USB chargers. And the task of finding a replacement for non-standardized pouch cell batteries can prove to be hard or impossible.

Looking at the ‘convenience’ argument from this way makes one wonder whether it is all just marketing that we’re being sold. Especially in light of the looming 2027 EU regulation on internal batteries that is likely to wipe out the existence of built-in batteries with an orbital legal strike. Are we about to say ‘good riddance’ to a terrible idea?

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Why Does The FCC Care About Computers?

October 23, 2025 by 18 Comments

Unless you are over a certain age, you probably take it for granted that electronic gadgets you buy have some FCC marking on them. But it wasn’t always true. [Ernie] submits that the FCC’s regulation of the computer industry was indirectly the result of the success of CB radio in that same time period.

Today, there is a high chance you don’t watch TV directly over the airwaves or even consume audio from a traditional radio station. Even if you do, the signal is increasingly likely to be digital. But only analog radio and TV were highly susceptible to interference. When a professional radio station or the power company interfered with you watching I Love Lucy, you could count on them to resolve it. Even ham radio operators, a small segment of the population, would, in general, graciously help you if their transmissions interfered with your equipment.

Never mind that, in many cases, it was the cheap TV or some other problem on the receiving end. Then there was another source of potential interference: CB radio. At first, you were about as likely to encounter a CB operator as a ham radio operator. But then in the 1970s, CB exploded, becoming a cultural phenomenon, and you can hear what a state it was in by watching the contemporary TV report in the video below.

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Making A Clock With A Retooled Unihiker K10

October 23, 2025 by 3 Comments

The Unihiker K10 is intended to be a small single-board solution for light AI and machine learning tasks. However, you don’t have to use it in that way if you don’t want to. [mircemk] figured out how to repurpose the device, and whipped up a simple Internet clock build to demonstrate how it’s done. 

While the Unihiker K10 is based on the common ESP32 microcontroller, out of the box, it isn’t compatible with standard Arduino libraries. However, [mircemk] had previously figured out how to get the K10 to play nice with the Arduino environment, building a simple light meter as a proof of concept. It just took a little tinkering to get everything playing nicely together, but soon enough, the TFT LCD and a light sensor were playing nicely with the K10 platform.

Moving forward, [mircemk] wanted to unlock more capability, so set about figuring out how to get WiFi and the onboard buttons working within the Arduino environment. A great way to test this was building a clock—the screen would show an analog clock face, the buttons would be used for control, and the WiFi would be used to query an NTP time server to keep it synced up and accurate.

It took a little work, particularly as the buttons are accessed through an external I/O expansion chip, but [mircemk] got there in the end. The clock may not be a particularly advanced project, but the write-up demonstrates how the K10 can readily be used with Arduino libraries for when you’re not interested in leveraging its fancier AI/ML capabilities.

We’ve seen a few good builds from [mircemk] before, too, like this neat proximity sensor. Continue reading “Making A Clock With A Retooled Unihiker K10” →

ESPTimeCastVFD

ESP32 Invades Old TV Box: Forecast More Than Just Channels

October 22, 2025 by 5 Comments

Obsolete hardware is all around us, and some of it has some pretty interesting tech buried within. One such device is an old Belgacom TV Box. Instead of using the ubiquitous LCD screen, it uses a VFD display for its user interface, and [Jean] has taken control of it with the ESPTimeCastVFD project.

Inside this box is a mix of two different 7-segment displays, which he uses to show the time and date, and 12 VFD displays, which are used to show weather data. To get the display working, the box was taken apart, and there were a few different areas [Jean] had to tap into: power for the soon-to-be-embedded ESP32-WROOM-32, as well as tying into the SPI lines to control the VFD. [Jean] also needed a 3.3V to 5V level shifter, and for this he used a 74LS125N dating all the way back to 1978.

The ESPTimeCast project, which we’ve featured here before, handles a lot of the time display and weather forecast shown on the front panel. However, [Jean] did have to add support for the VFD display, as well as adding wind speed to the display—as one of his uses for this is to judge the day’s suitability for flying RC planes. Once powered up, the ESP32 hosts a WiFi access point, allowing you to connect to it and set the configuration of the device, such as location, WiFi credentials, what displays you want to see, and many more. Thank you [Jean] for sending in your hack, saving this device from a landfill by turning it into a personalized display! Be sure to check out some of our other weather displays we’ve featured!

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UK’s MAST Upgrade Tokamak Stabilizes Plasma With Edge Magnetic Fields

October 22, 2025 by 16 Comments

Although nuclear fusion is exceedingly easy to achieve, as evidenced by desktop fusors, the real challenges begin to pop up whenever you try to sustain a plasma for extended periods of time, never mind trying to generate net energy output. Plasma instability was the reason why 1950s UK saw its nuclear fusion hopes dashed when Z-pinch fusion reactors failed to create a stable plasma, but now it seems that another UK fusion reactor is one step closer to addressing plasma instability, with the MAST Upgrade tokamak demonstrating the suppressing of ELMs.

ELMs, or edge localized modes, are instabilities that occur at the edge of the plasma. A type of magnetohydrodynamic instability, ELMs were first encountered after the switch to high-confinement mode (H-mode) to address instability issues encountered in the L-mode operating regime of previous tokamaks. These ELMs cause damage on the inside of the reactor vessel with these disturbances ablating the plasma-facing material.

One of the solutions proposed for ELMs are resonant magnetic perturbations (RMPs) using externally applied magnetic fields, with the South-Korean KSTAR tokamak already suppressing Type I ELMs using this method in 2011. Where the KSTAR and MAST Upgrade tokamaks differ is that the latter is a spherical tokamak, different from the more typical toroidal tokamak. As the name suggests, a spherical tokamak creates a sphere-like plasma rather than a doughnut-shape, with potential efficiency improvements.

All of this means that the MAST Upgrade tokamak can continue its testing campaign, as tokamaks around the globe keep trying to hit targets like the Greenwald Density Limit and other obstacles that stand in the way of sustained net energy production. Meanwhile stellarators seem to be surpassing one milestone after another, with the German Wendelstein 7-X being the current flagship project.

Top image: Inside MAST Upgrade,  showing the magnetic field coils used to control ELMs. Credit: United Kingdom Atomic Energy Authority

Tinkercad In Color

October 22, 2025 by 4 Comments

Tinkercad is famous for having lots of colors in the interface. But once you export an STL, that file is notoriously monochrome. If you are printing with a single color printer, no problems. But if you have a color printer, what do you do? [CHEP] shows some options, including a relatively new one, in the video below.

The simple way is to “paint” the STL inside your slicer. But as [CHEP] shows, that is a pain and also has some undesirable side effects. A better approach is to export each part (or, at least, each part of the same color) into separate STL files, which you can then import together in the slicer. You still have to paint, but you don’t have to select different faces, and the resulting coloring is more what you’d expect.

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