Keep An Eye On Your Air-Cooled Engine

October 23, 2025 by Bryan Cockfield 23 Comments

There was a time, long ago, when passenger vehicles used to be much simpler than they are today. There were many downsides of this era, safety chief among them, but there were some perks as well. They were in general cheaper to own and maintain, and plenty could be worked on with simple tools. There’s perhaps no easier car to work on than an air-cooled Volkswagen, either, but for all its simplicity there are a number of modern features owners add to help them with these antiques. [Pegor] has created his own custom engine head temperature monitor for these vehicles.

As one could imagine with an air-cooled engine, keeping an eye on the engine temperature is critical to ensuring their longevity but the original designs omitted this feature. There are some off-the-shelf aftermarket solutions but this custom version has a few extra features that others don’t. It’s based on a ATMega32u4 microcontroller and will work with any K-type thermocouple, and thanks to its open nature can use a wide array of displays. [Pegor] chose one to blend in with the rest of the instrumentation on this classic VW. The largest issue that needed to be sorted out was around grounding, but a DC-DC converter created an isolated power supply for the microcontroller, allowing the thermocouple to be bonded to the grounded engine without disrupting operation of the microcontroller.

The finished product looks excellent and does indeed blend in to the dashboard more than the off-the-shelf temperature monitor that was in use before. The only thing that is planned for future versions is a way to automatically dim the display when the headlights are on, as [Pegor] finds it a little bright at night. We also enjoy seeing anything that helps these antiques stay on the road more reliably as their modern descendants don’t have any of the charm or engineering of these classics.

A Logical Clock That Pretends To Be Analog

October 23, 2025 by Lewin Day 5 Comments

[kcraske] had a simple plan for their clock build. They wanted a digital clock that was inspired by the appearance of an analog one, and they only wanted to use basic logic, with no microprocessors involved. Ultimately, they achieved just that.

Where today you might build a clock based around a microcontroller and a real-time clock module, or by querying a network time server, [kcraske] is doing all the timekeeping in simpler hardware. The clock is based around a bunch of 74-series logic chips, a CD4060 binary counter IC, and a 32.768 KHz crystal, which is easy to divide down to that critical 1 Hz. Time is displayed on the rings of LEDs around the perimeter of the clock—12 LEDs for hours, and 60 each for minutes and seconds. Inside the rings, the ICs that make up the clock are arranged in a pleasant radial configuration.

It’s a nice old-school build that reminds us not everything needs to run at 200 MHz or hook up to the internet to be worthwhile. We’ve featured some other fun old-school clocks of late, too. Meanwhile, if you’re cooking up your own arcane timepieces, we’d love to hear about it on the tipsline.

These are test stampings-- the final product looks a lot better.

2025 Component Abuse Challenge: Nail Your Next Decal

October 23, 2025 by Tyler August 12 Comments

One of the hardest parts of a project — assuming it makes it that far — is finishing it up in an aesthetically pleasing manner. As they say, the devil is in the details, wearing Prada. Apparently the devil also has an excellent manicure, because [Tamas Feher] has come up with a way to introduce incredibly detailed decals (down to 0.1 mm) in cheap, repeatable fashion, using a technique borrowed from the local nail salon.

The end result can look quite a bit better than the test piece above.

For those who aren’t in to nail art (which, statistically speaking, is likely to be most of you) there is a common “stamping” technique for putting details onto human fingernails. Nail polish is first applied to voids on a stencil-like plate, then picked up by a smooth silicone stamper, which is then pressed against the nail, reproducing the image that was on the stencil. If that’s clear as mud, there’s a quick demo video embedded bellow.

There’s a common industrial technique that works the same way, which is actually where [Tamas] got the idea. For nail salons and at-home use, there are a huge variety of these stencils commercially available for nail art, but that doesn’t mean you’re likely to find what you want for your project’s front panel.

[Tamas] points out that by using a resin printer to produce the stencil plate, any arbitrary text or symbol can be used. Your logo, labels, whatever. By printing flat to the build plate, you can take advantage of the full resolution of the resin printer — even an older 2 K model would more than suffice here, while higher res like the new 16 K models become the definition of overkill. The prints go quick, as they don’t need any structural thickness: just enough to hold together coming off of the plate, plus enough extra to hold your designs at a 0.15 mm inset. That doesn’t seem very thick, but remember that this only has to hold enough nail polish to be picked up by the stamper.

[Tamas] cautions you have to work fast, as the thin layer of nail polish picked up by the stamper can dry in seconds. You’ll want plenty of nail polish remover (or plain acetone) on hand to clean the stamper once you’ve finished, as well as your stencil. [Tamas] cautions you’ll want to clean it immediately if you ever want to use it again. Good to know.

While this is going outside of the nail art kit’s comfort zone, it might not quite be abuse. It is however a very useful technique to add to our ever-growing quiver of how to make front panels. Besides, we don’t specify you have to literally make components suffer; we just want to see what wild and wonderful substitutions and improvisations you all come up with.

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Announcing The 2025 Hackaday Superconference Communicator Badge

October 23, 2025 by Elliot Williams 39 Comments

It’s the moment you hard-core hardware nerds have been waiting for: the reveal of the 2025 Hackaday Supercon Communicator Badge. And this year, we’ve outdone ourselves, but that’s thanks to help from stellar collaboration with folks from the community, and help from sponsors. This badge is bigger than the sum of its parts, and we’ve planned for it to be useful for you to hack on in the afterlife. Indeed, as always, you are going to be the final collaborator, so we can’t wait to see what you’ll do with it.

We’re going out – wide out – on a limb and trying to create a dense mesh network of badges talking to each other at Supercon. It’s going to be like a badge-hosted collection of chat rooms, as connected as we can make them without talking over each other.

You look up a topic, say Retro Computing or SAO trading, punch in the channel number on the numpad, and your badge starts listening to everything going on around that topic. But they also listen to everything else, and repeat anything they hear on to their neighbors. Like IRC, but LoRa.

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10 Cent Microcontroller Makes Music

October 23, 2025 by Lewin Day 10 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 Maya Posch 50 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 Al Williams 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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