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Our hacker from [Appalachian Forge Works] wrote in to let us know about their vending machine build: a Halloween vending computer that talks.

He starts by demonstrating the vending process: a backlit vend button is pressed, an animation plays on the screen as a synthetic voice speaks through attached speakers, the vending mechanism rotates until a successful vend is detected with a photoelectric sensor (a photoresistor and an LED) or a timeout of 10 seconds is reached (the timeout is particularly important for cases when the stock of prizes is fully depleted).

For a successful vend the prize will roll out a vending tube and through some ramps, visible via a perspex side panel, into the receptacle, as the spooky voice announces the vend. It’s the photoelectric sensor which triggers the mask to speak.

The vending mechanism is a wheel that spins, the bouncy balls caught in a hole on the wheel, then fall through a vending tube. The cache of prizes are stored in a clear container attached to the top, which is secured with a keyed lock attached to the 3D printed lid. After unlocking the lid can be removed for restocking.

The whole device is built into an old PC case tower. The back panels have been replaced and sealed. The computer in the box is an ASUS CN60 Chromebox running Ubuntu Linux. The power button is obscured on the back of the case to avoid accidental pressing. The monitor is bolted on to the side panel with a perspex screen and connected to the Chromebox via VGA. Inside there are two power supplies, an Arduino Uno microcontroller, and an audio amplifier attached to a pair of speakers.

A 12V DC motor controls the vending prize wheel which feeds a prize into the vending tube. The vending tube has an LED on one side and a photoresistor on the other side that detects the vend. The software, running on Linux, is Python code using the Pygame library.

If you’re interested in vending machines you might also be interested in this one: This Vending Machine Is For The Birds.

Thanks to [Adam] for writing in about this one.

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As we all look across a sea of lifeless, nearly identically-styled consumer goods, a few of us have become nostalgic for a time when products like stereo equipment, phones, appliances, homes, cars, and furniture didn’t all look indistinguishable. Computers suffered a similar fate, with nearly everything designed to be flat and minimalist with very little character. To be sure there are plenty of retro computing projects to recapture nostalgia, but to get useful, modern hardware in a fun, retro-themed case check out this desktop build from [Mar] that hides a few unique extras.

The PC itself is a modern build with an up-to-date operating system, but hidden in a 386-era case with early-90s styling. The real gem of this build though is the floppy disk drive, which looks unaltered on the surface. But its core functionality has been removed and in its place an Arduino sits, looking for NFC devices. The floppy disks similarly had NFC tags installed so that when they interact with the Arduino,it can send a command to the computer to launch a corresponding game. To the user it looks as though the game loads from a floppy disk, much like it would have in the 90s albeit with much more speed and much less noise.

Modern industrial design is something that we’ve generally bemoaned as of late, and it’s great to see some of us rebelling by building unique machines like this, not to mention repurposing hardware like floppy drives for fun new uses (which [Mar] has also open-sourced on a GitHub page). It’s not the first build to toss modern hardware in a cool PC case from days of yore, either. This Hot Wheels desktop is one of our favorites.

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You know how it goes — some gadgets stick around in your toolbox far longer than reason dictates, because maybe one day you’ll need it. How many of us held onto ISA diagnostic cards long past the death of the interface?

But unlike ISA, USB isn’t going away anytime soon. Which is exactly why this USB and more tester by [Iron Fuse] deserves a spot in your toolbox. This post is not meant to directly lure you into buying something, but seen how compact it is, it would be sad to challenge anyone to reinvent this ‘wheel’, instead of just ordering it.

So, to get into the details. This is far from the first USB tester to appear on these pages, but it is one of the most versatile ones we’ve seen so far. On the surface, it looks simple: a hand-soldered 14×17 cm PCB with twelve different connectors, all broken out to labelled test points. Hook up a dodgy cable or device, connect a known-good counterpart, and the board makes it painless to probe continuity, resistance, or those pesky shorts where D+ suddenly thinks it’s a ground line.

You’ll still need your multimeter (automation is promised for a future revision), but the convenience of not juggling probes into microscopic USB-C cavities is hard to overstate. Also, if finding out whether you have a power-only or a data cable is your goal, this might be the tool for you instead.

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We often think that if a piece of software had the level of documentation you usually see for hardware, you wouldn’t think much of it. Sure, there are exceptions. Some hardware is beautifully documented, and poorly documented software is everywhere. [Graham Sutherland’s] been reviewing schematics and put together some notes on what makes a clean schematic.

Like coding standards, some of these are a bit subjective, but we thought it was all good advice. Of course, we’ve also violated some of them when we are in a hurry to get to a simulation.

Most of the rules are common sense: use enough space, add labels, and avoid using quirky angles. [Flannery O’Connor] once said, “You can do anything you can get away with, but nobody has ever gotten away with much.” She was talking about writing, but the same could be said about schematics.

[Graham] says as much, pointing out that these are more guidelines. He even points out places where you might deliberately break the rules. For example, in general, wires should always go horizontally or vertically. However, if you are crossing two parallel wires, you probably should take advantage of the diagonals.

So what are your schematic rules? Software has standards like MISRA, CERT, and various NASA standards. Oddly enough, one of our favorite quick schematic editors is truly terrible but obeys most of these rules. But you can surely do better than that.

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Few toys are more iconic than the Etch A Sketch, which has been popular for 65 years now. In that time, more than 100 million units have been sold worldwide. And every single one of them has had the same problem: the lack of an “undo” button. If you mess up your masterpiece, your only choice is to give the Etch A Sketch a good shake and start over. That’s an unavoidable result of the Etch A Sketch’s drawing mechanism, which Tekavou overcame by building a digital “Teka-Sketch.”

An Etch A Sketch is a two-dimensional manually operated cable-driven plotter with a stylus that scrapes a whitish aluminum powder off the screen, leaving a transparent line that looks dark because the interior of the enclosure is unlit. When you shake the whole thing, the aluminum powder sticks back onto the screen and “erases” the entire drawing. That mechanism doesn’t leave room for a simple solution for erasing portions of lines, which is why complex drawings induce so much anxiety.

The Teka-Sketch is a digital device and it can arbitrarily draw or erase lines in whatever manner its programming dictates. In this case, Tekavou kept it simple and mimicked most of the functionality of an Etch A Sketch. There are still two knobs to control movement of the virtual stylus in the X and Y axes, and it still draws straight darkish lines on a whitish background. The big change is the introduction of an “undo” button (clicking the left knob), which erases the most recent few centimeters of the line.

The key component in the Teka-Sketch is an Inkplate 6 from a brand called Soldered Electronics. The basic unit combines a high-quality 6” e-paper display with an ESP32 microcontroller, and there are also packages available with an enclosure and battery. Tekavou simply added a couple of rotary encoders and packed everything into a custom 3D-printed enclosure. Everything else was coding, which Tekavou first started learning as a kid after discovering NIBBLES.BAS —a Snake variant programmed in QBasic.

As an homage to that formative experience, Tekavou created a Nibbles game that runs on the Teka-Sketch. It even has a two-player mode, with two onscreen snakes (one controlled by the left knob and one controlled by the right knob). E-paper screens are notorious for poor refresh rates, which is why they aren’t more common, but the Inkplate 6’s screen has partial refresh rates fast enough to make the game perfectly playable.

Now Tekavou’s own kids can share some of the experiences he had as a child, but in a way that has been improved with technology.

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Fluid-Implicit-Particle or FLIP is a method for simulating particle interactions in fluid dynamics, commonly used in visual effects for its speed. [Nick] adapted this technique into an impressive FLIP business card.

The first thing you’ll notice about this card is its 441 LEDs arranged in a 21×21 matrix. These LEDs are controlled by an Raspberry Pi RP2350, which interfaces with a LIS2DH12TR accelerometer to detect card movement and a small 32Mb memory chip. The centerpiece is a fluid simulation where tilting the card makes the LEDs flow like water in a container. Written in Rust, the firmware implements a FLIP simulation, treating the LEDs as particles in a virtual fluid for a natural, flowing effect.

This eye-catching business card uses clever tricks to stay slim. The PCB is just 0.6mm thick—compared to the standard 1.6mm—and the 3.6mm-thick 3.7V battery sits in a cutout to distribute its width across both sides of the board. The USB-C connection for charging and programming uses clever PCB cuts, allowing the plug to slide into place as if in a dedicated connector.

Inspired by a fluid simulation pendant we previously covered, this board is just as eye-catching. Thanks to [Nick] for sharing the design files for this unique business card. Check out other fluid dynamics projects we’ve featured in the past.

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Normally when you think solar projects, you think of big photovoltaic cells. But a photodiode is just an inefficient, and usually much smaller, PV cell. Since [Pocket Concepts]’s Solar_nRF has such a low power budget, it can get away with using BPW34 photodiodes in place of batteries. (Video, embedded below.)

The BPW34 silicon PIN photodiode feeds a small voltage into a BQ25504 ultra-low-power boost converter energy harvester which stores power in a capacitor. When the capacitor is fully charged the battery-good pin is toggled which drives a MOSFET that powers everything downstream.

When it’s powered on, the Nordic nRF initializes, reads the current temperature from an attached I2C thermometer, and then sends out a Bluetooth Low Energy (BLE) advertising packet containing the temperature data. When the capacitor runs out of energy, the battery-good pin is turned off and downstream electronics become unpowered and the cycle begins again.

[Pocket Concepts] uses a Nordic Semiconductors Power Profiler Kit II to help determine charge requirements. He calculates that 37 uF would be enough power for a single cycle, then uses 100 uF to get between one and three transmissions done using a single charge.

[Pocket Concepts] finishes his video with a request for project ideas. Is this a soil moisture meter? Earrings that monitor your biometrics? Something else? If you have some ideas of your own please sound off in the comments!

[Pocket Concepts] said he was inspired by Ultra low power energy harvester from BPW34 over on Hackaday.io, be sure to check that out for some interesting low-power project ideas. If you’re interested in other applications for Nordic nRF chips check out ESP32 Turned Handy SWD Flasher For NRF52 Chips and Ground Off Part Number Leads To Chip Detective Work for some examples.

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Engineezy, formerly known as JBV Creative or Jay BV, builds really impressive machines. But most of them are large and portability isn’t a feature he usually cares about. That was a problem when Engineezy decided to attend Open Sauce 2025, which has become the biggest maker event of the year. He wanted something to show off while he perused the various booths and nothing he had previously built fit the bill. So, he reimagined his marble pixel art machine as a wearable fashion piece for strutting around Open Sauce.

We covered Engineezy’s original marble pixel art machine last year and it was really impressive. On demand, it could arrange colored marbles in several columns to form a grid of “pixels” that create an image. Each image had a resolution of 32×32, which required a total of 1024 marbles. In practice, the machine needed many, many more marbles than that in order to accommodate the colors of different images. The resulting machine was pretty massive and the best way for Engineezy to make it more portable was to reduce the image resolution to 11×11 (yes, there is a reason for the odd numbers) and the color palette to two.

Engineezy came up with a clever way to get the marbles into the desired columns: binary gates. They work a bit like transistors, creating a path like tree roots that the marbles can follow. Through the power of doubling at each stage, one input eventually leads to 12 outputs — only two of the four legs on the second stage were doubled. That 12th output is there so the machine can recirculate marbles that are the wrong color.

Unlike the original machine, this one only produces black-and-white images. So, if it needs a white marble and both of the hoppers have a black marble next in line, it will simply send a black marble back down into the hopper and hope a white marble comes up next (repeating if it has especially bad luck).

The gates are actuated by servo motors and marbles feed from the hopper back to the top with a double auger mechanism. A final stop mechanism holds all of the marbles in place in the columns until it is time to reset the image, at which point a servo moves to release them back into the hoppers.

Finally, Engineezy mounted the machine onto laser-cut plates attached to the back of a jacket, so he could walk the floors of Open Sauce while everyone admired his handywork.

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Guitar Hero was all the rage for a few years, before the entire world apparently got sick of it overnight. Some diehards still remember the charms of rhythm games, though. Among them you might count [Joseph Valenti] and [Daniel Rodriguez], who built a Keyboard Hero game for their ECE 4760 class at Cornell.

Keyboard Hero differs quite fundamentally from Guitar Hero in one major way. Rather than having the player tackle a preset series of “notes,” the buttons to press are instead procedurally generated by the game based on incoming audio input. It only works with simple single-instrument piano music, but it does indeed work. A Raspberry Pi Pico is charged with analyzing incoming audio and assigning the proper notes. Another Pi Pico generates the VGA video output with the game graphics, which is kept in sync with the audio pumped out from the first Pico so the user can play the notes in time with the music. Rather than a guitar controller, Keyboard Hero instead relies on five plastic buttons assembled on a piece of wood. It works.

It’s obviously not as refined as the game that inspired it, but the procedural generation of “notes” reminds us of old-school rhythm game Audiosurf. Video after the break.

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