Ancient Pocket Computer Gets A Serious Serial Upgrade

March 25, 2025 by Lewin Day 9 Comments

[Robert’s Retro] is one of those great YouTube channels that shows us the ins and outs of old and obscure computers. [Robert] likes going a step beyond the traditional teardown though, repairing and upgrading these old machines. His latest project involves giving the ZEOS Pocket PC a fully-functional serial port.

If you’re unfamiliar with the ZEOS Pocket PC, you might know it as the Tidalwave PS-1000—it’s a pretty straightforward clone. Originally, these machines could be had with a proprietary serial adapter to enable them to interface with external peripherals. However, like most obscure cables and connectors from three decades ago, they’re virtually unobtainable today.

To solve this problem, [Robert] decided to hack in a traditional DE-9 connector instead. Commonly referred to as the DB-9, this is the most common serial port design used on IBM PCs and compatibles. Getting the larger port into the compact PC required some careful hacking of the case, as well as delicate soldering to hook up the pins to the right signals on the tightly-packed motherboard. This video does involve cutting some vintage plastic, but overall it’s a very neat mod that is handled with due respect and care.

This isn’t the first time we’ve seen him upgrade a classic portable computer, either.

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Metal Detector Built With Smartphone Interface

March 25, 2025 by Lewin Day 8 Comments

If you think of a metal detector, you’re probably thinking of a fairly simple device with a big coil and a piercing whine coming from a tinny speaker. [mircemk] has built a more modern adaptation. It’s a metal detector you can use with your smartphone instead.

The metal detector part of the project is fairly straightforward as far as these things go. It uses the pulse induction technique, where short pulses are fired through a coil to generate a magnetic field. Once the pulse ends, the coil is used to detect the decaying field as it spreads out. The field normally fades away in a set period of time. However, if there is metal in the vicinity, the time to decay changes, and by measuring this, it’s possible to detect the presence of metal.

In this build, an ESP32 is in charge of the show, generating the necessary pulses and detecting the resulting field. It’s paired with the usual support circuitry—an op-amp and a few transistors to drive the coil appropriately, and the usual smattering of passives. The ESP32 then picks up the signal from the coil and processes it, passing the results to a smartphone via Bluetooth.

The build is actually based on a design by [Neco Desarrollo], who presents more background and other variants for the curious. We’ve featured plenty of [mircemk]’s projects before, like this neat proximity sensor build. Continue reading “Metal Detector Built With Smartphone Interface” →

Glow In The Dark PCBs Are Pretty Cool

March 24, 2025 by Lewin Day 11 Comments

What if circuit boards could glow in the dark? It’s a fun question, and one [Botmatrix] sought to answer when approached by manufacturer PCBWay to run a project together. It turns out that it’s quite possible to make glowing PCBs, with attractive results. (Video after the break.)

Specifically, PCBWay has developed a workable glow-in-the-dark silkscreen material that can be applied to printed circuit boards. As a commercial board house, PCBWay hasn’t rushed to explain how precisely they pulled off this feat, but we don’t imagine that it involved anything more than adding some glow-in-the-dark powder to their usual silkscreen ink, but we can only speculate.

On [Botmatrix]’s end, his video steps through some neat testing of the performance of the boards. They’re tested using sensors to determine how well they glow over time.

It might seem like a visual gimmick, and to an extent, it’s just a bit of fun. But still, [Botmatrix] notes that it could have some practical applications too. For example, glow-in-the-dark silkscreen could be used to highlight specific test points on a board or similar, which could be instantly revealed with the use of a UV flashlight. It’s an edge case, but a compelling one. It’s also likely to be very fun for creating visually reactive conference badges or in other applications where the PCB plays a major cosmetic role.

[Botmatrix] says these are potentially the first commercially-available glow-in-the-dark printed PCBs. We love glow in the dark stuff; we’ve even explored how to make your own glowing material before, too. .

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PPS Is The Hottest USB-C Feature You Didn’t Know About

March 24, 2025 by Lewin Day 28 Comments

USB Power Delivery is widely considered to be a good thing. It’s become relatively standard, and is a popular way for makers to easily power their projects at a number of specific, useful voltages. However, what you may not know is that it’s possible to get much more variable voltages out of some USB chargers out there. As [GreatScott!] explains, you’ll want to meet USB-C PPS.

PPS stands for Programmable Power Supply. It’s a method by which a USB-C device can request variable voltage and current delivery on demand. Unlike the Power Delivery standard, you’re not limited to set voltages at tiers of 5V, 9V, 15V and 20V. You can have your device request the exact voltage it wants, right from the charger. Commercially, it’s most typically used to allow smartphones to charge as fast as possible by getting the optimum voltage to plumb into the battery. However, with the right techniques, you can use PPS to get a charger to output whatever voltage you want, from 3.3 V to 21 V, for your own nefarious purposes. You can choose a voltage in 20 mV increments, and even set a current limit in 50 mA increments. Don’t go mad with power, now.

However, there’s a hitch. Unlike USB PD, there isn’t yet a whole ecosystem of $2 PPS breakout boards ready to gloop into your own little projects. As [GreatScott!] suggests, if you want to use PPS, you might want to take a look at the AP33772S IC. It’s a USB PD3.1 Sink Controller. You can command it over I2C to ask for the voltage and current you want. If that’s too hard, though, [CentyLab] has a solution on Tindie to get you going faster. It’s also got some exciting additional functionality—like USB-C AVS support. It offers higher voltage and more power, albeit with less resolution, but chargers with this functionality are quite obscure at this stage.

We’ve actually touched on PPS capability before in our exploration of the magic that is USB-C Power Delivery. Video after the break.

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Mural: The Plotter That Draws On Walls

March 24, 2025 by Lewin Day 15 Comments

Let’s say you’ve got a big bare wall in your home, and you want some art on it. You could hang a poster or a framed artwork, or you could learn to paint a mural yourself. Or, like [Nik Ivanov], you could build a plotter called Mural, and get it to draw something on the wall for you.

The build is straightforward enough. It uses a moving carriage suspended from toothed belts attached to two points up high on the wall. Stepper motors built into the carriage reel the belts in and out to move it up and down the wall, and from side to side. In this case, [Nik] selected a pair of NEMA 17 steppers to do the job. They’re commanded by a NodeMCU ESP32, paired with TMC2209 stepper motor drivers. The carriage also includes a pen lifter, which relies on a MG90s servo to lift the drawing implement away from the wall.

The build is quite capable, able to recreate SVG vector graphics quite accurately, without obvious skew or distortion. [Nik] has been using the plotter with washable Crayola markers, so he can print on the wall time and again without leaving permanent marks. It’s a great way to decorate—over and over again—on a budget. Total estimated cost is under $100, according to [Nik].

We’ve featured some neat projects along these lines before, too. Video after the break.

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The SNES Seems To Be Getting Faster Over Time

March 24, 2025 by Lewin Day 24 Comments

Every Super Nintendo console should run at the same speed. They were all built in factories with the same components so they should all operate at the steady clip mandated by Nintendo all those years ago. Except, apparently, the SNES is speeding up as it gets older.

The matter was brought to the public’s attention by the [TASBot] team, a group within the speedrunning community. If anyone was going to notice vintage consoles suddenly running a hair faster, you could bet it would be the speedrunners. Soon enough, a call was put out to crowdsource some data. Submitters were asked to run a set piece of code to test the DSP sample rate on consoles when cold and warm, to get the best idea of what was going on.

As reported by Ars Technica, the group seems to have pinned down the problem to the SNES’s Audio Processing Unit. It’s supposed to run at 24.576 MHz, with a sample rate of 32,000 Hz. However, over the years, emulator developers and speedrunners had noticed that 32,040 Hz seemed to be a more realistic figure for what real consoles were actually running the DSP sample rate at. Developers found that building emulators to run the DSP at this rate was important to run commercial games as expected, suggesting the hardware might have always been a little faster than expected.

However, more recently, it seems that the average speed of the DSP sample rate has increased further. The average result collected by [TASBot] from modern consoles is 32,076 Hz. What’s more interesting is the range of submitted figures—from 31,976 Hz to 32,349 Hz. It seems that the DSP’s ceramic resonator—used instead of a quartz crystal—might degrade over time, causing the speedup. [TASBot] team members also tested temperature changes, but only found a 32 Hz variation from a frozen SNES to one at room temperature.

The fact that console components degrade over time isn’t exactly news; we’ve featured plenty of articles on leaky batteries and corroded traces. Still, for speedrunners, the idea that the hardware standard itself can shift over time? It’s like feeling quicksand under your feet. What even is reality anymore?

[Thanks to s7726 for the tip!]

A Cute Handheld Gaming Device That You Can Build In An Altoids Tin

March 21, 2025 by Lewin Day 10 Comments

The MintyPi was a popular project that put a Raspberry Pi inside an Altoids tin to make a pocketable gaming handheld. Unfortunately, it’s not the easiest build to replicate anymore, but [jackw01] was still a fan of the format. Thus was born the Pi Tin—a clamshell handheld for portable fun!

Neat, huh? More pocket-sized than the Game Boy Pocket.

The build is based around the Raspberry Pi Zero 2W, which packs more power than the original Pi Zero into the same compact form factor. It’s combined with a 320 x 240 TFT LCD screen and a 2000 mAh lithium-polymer battery which provides power on the go.

There are also a pair of custom PCBs used to lace everything together, including the action buttons, D-pad, and power management hardware. Depending on your tastes, you have two main enclosure options. You can use the neat 3D printed clamshell seen here in beautiful teal, or you can go with the classic Altoids tin build—just be careful when you’re cutting it to suit! Files can be found on GitHub for the curious.

We love a good handheld project around these parts; it’s particularly awesome how much gaming you can fit in your pocket given the magic of the Raspberry Pi and modern emulation. If you’re cooking up your own little retro rig, don’t hesitate to let us know!