Slightly Sentient D20 Might Subtly Shift Your Rolls

May 25, 2026 by Donald Papp 2 Comments

A twenty-sided die (d20) is a common thing in tabletop gaming, and [kati]’s slightly sentient d20 is a PCB that not only delivers random results on demand, but responds to hot and cold streaks and may even tweak the results a little to reflect its mood.

On its face the unit is a touch-sensitive PCB with twenty small charlieplexed LEDs around its perimeter, one for each die result. When activated by a touch on the center pad, the die dutifully animates a die roll and delivers a result. But something happens if the RNG (random number generator) coughs up results that are unusually lucky, or unlucky.

After a streak of natural 1s, the device gets cranky. It begins to ignore the occasional activation input, and may glitch before a roll, reflecting a low mood. In addition, future rolls while in a low mood have a slight chance of being silently discarded and re-rolled into a low range (1-6), prolonging the unlucky streak. The inverse is true of a die that encounters a lucky run of natural 20s, with the die’s mood shifting to high spirits and having a slight chance of re-rolling future results into a high range (16-20).

The idea is to create (and feed) the feeling of lucky and unlucky streaks. Gamers are of course perfectly capable of projecting such feelings all on their own, which means the die acts as both mirror and amplifier of these emotions. In addition, each die acts slightly differently as a result of being imprinted with different RNG seeds, timing values, and response times which makes each one feel unique. There are reportedly other hidden features as well.

If you’d like to try making your own, keep an eye on the GitHub repository. The originals have design elements that were heavily personalized for [kati]’s gaming group, so the design files are in the process of being turned into a meaningful public release. Of course, there’s more than enough detail already to roll your own if you are so inclined.

PCB Map Display Keeps An Eye On Family

May 23, 2026 by Zoe Skyforest 22 Comments

PCBs are traditionally designed with traces laid out to support a circuit full of electronic components. However, they’ve become increasingly popular as a way to produce functional visual artworks. This PCB map from [Jonathan] is a great example.

The PCB was designed as a map of the California East Bay area. The roads are laid out as the top-side copper layer, while the land and roads are used for the top solder mask layer, with the flipped land and roads area making up the solder mask on the bottom side. The map data itself was cribbed from Snazzy Maps. Behind the PCB, [Jonathan] mounted a 64 x 32 RGB LED array, which can be seen glowing through from behind the material. The LEDs are controlled by an ESP32, which grabs location data from [Jonathan’s] family member’s mobile devices over MQTT, and uses it to light their positions on the map. Files are on Github for the curious.

If you’ve got a family that is open to location tracking, and the money to pay for a custom PCB, you could probably recreate this project yourself. We’ve seen some other great PCB maps before, too, like this amazing metro tracker.
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You’ve Seen The Chip Shortage And The Memory Shortage, Now Prepare For The PCB Shortage

May 6, 2026 by Jenny List 45 Comments

It’s nice to hide away in our little corner of the internet and talk tech, safely away from the turmoil of world events. Sometimes though, geopolitics intrude even into our space, and Reuters are here reporting on a new concern that will probably affect many Hackaday readers. Conflict in the Gulf of Arabia, and in particular raids on Saudi petrochemical plants, is threatening PCB production far away in China.

Most of us probably have a mental image of tankers sailing through the Strait of Hormuz laden with Gulf crude, off to be processed by refineries somewhere else in the world. Certainly a load of oil takes just that route, but for the Saudis and other oil-producing nations in the region, it also makes economic sense to site petrochemical industries at source. They export the much more valuable refined products, among which is the polymer resin used in PCB production. The Reuters report says that consequent to this and a rise in copper prices, the cost of a PCB in China has risen by 40%. Naturally this doesn’t sound like good news.

Here at Hackaday, when it comes to component shortages this isn’t our first rodeo. We’re in the middle of a memory shortage due to AI companies, and the COVID-era chip shortage is still fresh in our minds. Unfortunately, this type of thing as been a regular of the technology world for decades. Here we are with another one, and should we be worried? In the short term it’s certainly a concern as the Gulf conflict is still searching for an end to its uneasy stalemate, but remembering previous shortages we think that global industry will adapt and expand other sources where necessary. Just as with the similar IC encapsulation resin shortage back in the ’90s, it may eventually be the panic more than the shortage which becomes responsible for the price hikes.

We’ve taken an abstract look at global electronic supply chains before.

Header image: Gabriela P., CC BY 4.0.

A Candle-Powered Light

February 23, 2026 by Bryan Cockfield 25 Comments

For a little over two thousand years, the primary light sources after the sun had set were oil lamps and candles. This was well before the age of fossil fuels, so these oil lamps were often fueled with a labor-intensive agricultural product like olive oil. Candles were similarly difficult to make, made from tallow, beeswax, or even butter. Labor and materials costs aside, though, there’s a surprising amount of energy in these fuels and [Maciej Nowak Projects] has a generator that help these ancient light sources generate some electricity on the side.

The generator is based around a piece of technology called a thermoelectric generator (TEG), which produces a voltage potential when placed in a temperature gradient. These aren’t new technologies, but their typically low efficiencies limit where they can be effectively used. In this case, however, [Maciej Nowak] has gone to great effort to boost this efficiency as high as possible by using a huge radiator on the cool side of the TEG and another one on the hot side, which in this case is heated by a small tea candle. The electricity produced is sent to a tiny DC converter which regulates the voltage to 3.3V, which then powers two custom-built pedestal lamps on either side of the TEG, each with a high-efficiency LED mounted to a custom-made circuit board.

Although this is certainly not the first time a TEG has been set up to run a small lighting system, we do appreciate this one for its polish, design, and high efficiency. It would make a fitting addition to anyone’s emergency power outage kit as it really increases the amount of available light produced from any given candle. When taken to the extreme, though, thermoelectric generators can be made to produce a surprising amount of energy, provided they are placed in the right environment.

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New Tool Makes 3D Printed PCBs, Fast

February 19, 2026 by Zoe Skyforest 44 Comments

Getting PCBs made is often the key step in taking a dodgy lab experiment and turning it into a functional piece of equipment. However, it can be tedious to wait for PCBs to ship, and that can really slow down the iterative development process. If you’ve got a 3D printer, though, there’s a neat way to make your own custom PCBs. Enter PCB Forge from [castpixel].

The concept involves producing a base and a companion mold on your 3D printer. You then stick copper tape all over the base part, using the type that comes with conductive adhesive. This allows the construction of a fully conductive copper surface across the whole base. The companion mold is then pressed on top, pushing copper tape into all the recessed traces on the base part. You can then remove the companion mold, quickly sand off any exposed copper, and you’re left with a base with conductive traces that are ready for you to start soldering on parts. No etching, no chemicals, no routing—just 3D printed parts and a bit of copper tape. It rarely gets easier than this.

You can design your PCB traces in any vector editor, and then export a SVG. Upload that into the tool, and it will generate the 3D printable PCB for you, automatically including the right clearances and alignment features to make it a simple press-together job to pump out a basic PCB. It bears noting that you’re probably not going to produce a four-layer FPGA board doing advanced high-speed signal processing using this technique. However, for quickly prototyping something or lacing together a few modules and other components, this could really come in handy.

The work was inspired by a recent technique demonstrated by [QZW Labs], which we featured earlier this year. If you’ve got your own hacks to speed up PCB production time, or simply work around it, we’d love to know on the tipsline! Video after the break.

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Cheetah MX4 Mini: A Pint-Sized 3D Printer Controller

December 28, 2025 by Matt Varian 31 Comments

There’s a seemingly unending list of modifications or upgrades you can make to a 3D printer. Most revolve around the mechanical side of things, many are simple prints or small add-ons. This upgrade is no small task: this 17-year-old hacker [Kai] took on designing and building his own 3D printer control motherboard, the Cheetah MX4 Mini.

He started the build by picking out the MCU to control everything. For that, he settled on the STM32H743, a fast chip with tons of support for all the protocols he could ask for, even as he was still nailing down the exact features to implement. For stepper drivers, [Kai] went with four TMC stepstick slots for silent motor control. There are provisions for sensorless homing and endstops, support for parallel and serial displays, and both USB-C and microSD card slots for receiving G-code. It can drive up to three fans as well as two high-amperage loads, such as for the heated bed.

All these features are packed into a board roughly the size of a drink coaster. Thanks to the STM32H743, the Cheetah MX4 Mini supports both Marlin and Klipper firmware, a smart choice that lets [Kai] leverage the massive amount of work that’s already gone into those projects.

One of the things that stood out about this project is the lengths to which [Kai] went to document what he did. Check out the day-by-day breakdown of the 86 hours that went into this build; reading through it is a fantastic learning aid for others. Thanks [JohnU] for sending in this tip! It’s great to see such an ambitious project not only taken on and accomplished, but documented along the way for others to learn from. This is a fantastic addition to the other 3D printer controllers we’ve seen.

A PCB Can Be A Hydrofoil, If It Really Wants To

November 23, 2025 by Tyler August 10 Comments

You know those old cliche that the younger generations have begun to cynically despise: “follow your dreams!” “You can be anything you put your mind to!” — well, perhaps they are true on occasion. For instance when [rctestflight] had PCBs that dreamed of becoming a hydrofoil, he found a way to make that dream come true.

It’s kind of obvious in retrospect: printed circuit boards are made of FR4, which is a form of fiberglass, and you know what else is commonly made of fiberglass? Boats. So yes, the material is suited for this task. The fact that solder joints hold up to use in a little remote-control hydrofoil is less obvious, but good to know. It certainly makes for easier assembly for those of us who have developed an allergy to epoxy.

Ease of assembly wasn’t really the point here: the point was that by making the “mast” of the hydrofoil out of PCB– that’s the part that holds the underwater wing– [rctestflight] figured he could (shock!) print a circuit onto it. Specifically, a liquid-level sensor, and because microcontrollers are so cheap these days he went the “total overkill” route of embedding an ESP32 on each mast. He started with a resistive sensor, but since those self-corrode too quickly, the team switched to a capacitive sensor that doesn’t need to form a galvanic cell in salt water. Come to think of it, that might still be a problem with the solder joint between the PCBs. Good thing nobody will be riding this one.

Having such a sensor and brain close-coupled allows for a faster control loop than the sonar [rctestflight] had previously been using to control his hydrofoil’s altitude.. Pivoting each mast with its own servo made for a smooth flight over the water— well, once they got the PID tuning set, anyway. Check it out in the video embedded below.

We’ve seen PCB used for enclosures before, and even the chassis of a rover, but using it for a hydrofoil is a new hack. Continue reading “A PCB Can Be A Hydrofoil, If It Really Wants To” →