Time to enjoy your favorite TV shows. (Credit: SpaceTime Junction, YouTube)

Vend-o-Vision: Trading Quarters For Watching TV In Public

February 28, 2026 by Maya Posch 16 Comments

The timer mechanism of the Vend-o-Vision. (Credit: SpaceTime Junction, YouTube)

There was a time before portable TVs and personal media players when the idea of putting coin-operated TVs everywhere, from restaurants to airports and laundromats, would have seemed like a solid business model. Thus was born the Vend-o-Vision by Mini-TV USA, which presented itself as a cash earner for businesses and a way to make their customers even happier. One of these new-in-box units recently made its way over to [Mark] of the SpaceTime Junction YouTube channel.

This unit is very simple, with what appears to be an off-the-shelf Panasonic black-and-white TV with UHF and VHF reception capability, inside a metal box that contains the timer mechanism, which is linked to the coin mechanism. Depending on a physical slider with three positions, you get anywhere from 10 to 20 minutes per quarter, with the customer having to tune into the station themselves using the TV’s controls. A counter mechanism is provided as an option.

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Argon ONE UP: Test-Tasting A Raspberry Pi CM5 Based Laptop

February 12, 2026 by Maya Posch 21 Comments

The Raspberry Pi Compute Module form factor is a tantalizing core for a potential laptop, with a CM5 module containing a fairly beefy SoC and RAM, with depending on the exact module also eMMC storage and WiFi. To turn this into a laptop you need a PCB to put the CM5 module on and slide it into a laptop shell. This is in effect what [Argon40] did with their crowdfunded ONE UP laptop, which [Jeff Geerling] has been tinkering with for a few weeks now, with some thoughts on how practical the concept of a CM5-based laptop is.

Most practical is probably the DIY option that [Jeff] opted for with the ‘Shell’ version that he bought, as that meant that he could pop in one of the CM5s that he had lying around. The resulting device is totally functional as a laptop, with all the Raspberry Pi 5 levels of performance you’d expect and with the repair-friendliness of a Framework laptop.

If you’re buying the Core version with the 8 GB CM5 module and 256 GB NVMe SSD included, you’re looking at €475 before shipping or the equivalent in your local currency. This puts it unfortunately in the territory of budget x86 laptops and used Apple MacBooks, even before taking into account the current AI-induced RAMpocalypse that’d push [Jeff]’s configuration to $600 if purchased new, with prices likely to only go up.

Even if this price isn’t a concern, and you just want to have a CM5-based laptop, [Jeff]’s experience got soured on poor customer support from [Argon40] and above all the Raspberry Pi’s arch nemesis: the inability to do sleep mode. With the lid closed it runs at 3.3 W idle, but that’ll run down the battery from 100% to flat in about 17 hours. Perhaps if Raspberry Pi added sleep states to their systems would it make for a good laptop core, as well as for a smartphone.

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Testing A Continuous Printing Mod For The Bambu Lab A1 Mini

January 16, 2026 by Maya Posch 9 Comments

There are a few types of continuous 3D printing with FDM printers, with a conveyer belt and automatic build plate swapping the most common types. The advantage of build plate swapping is that it automates the bit where normally a human would have to come in to remove finished parts from the build plate. A recent entry here is the Chitu PlateCycler C1M which the [Aurora Tech] YouTube channel had over for a review. This kit bolts onto the Bambu Lab A1 Mini FDM printer and comes with four extra PEI build plates for a not unreasonable $79 (€69).

As also noted in the review video, this is effectively a clone of the original swapmod A1m kit, but a big difference is that the Chitu kit comes with all of the parts and doesn’t require you to print anything yourself.

The different plates are prepared using a special tool that inserts G-code between the plate changes. Moving the bed in a specific way triggers the switch that lifts the finished plate off the magnetic bed by the plastic grip on the plate and loads a fresh plate from the stack. Here it was found that a small tolerance issue prevented the last plate from being used, but some sandpaper fixed this. Other than that it was a fairly painless experience, and for e.g. multi-color prints with separated colors – as demonstrated – it would seem to be a great way to churn out the entire model without manual intervention or a lot of wasted filament.

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Trying Out The Allwinner-Based Walnut Pi SBC

January 16, 2026 by Maya Posch 35 Comments

When it comes to the term ‘Raspberry Pi clones’, the most that they really clone is the form factor, as nobody is creating clones of Broadcom VideoCore-based SoCs. At least not if they want to stay safe from Broadcom’s vicious legal team. That said, the Walnut Pi 1B single-board computer (SBC) that [Silly Workshop] recently took a gander at seems to be taking a fairly typical approach to a Raspberry Pi 4 form factor compatible board.

Part of Walnut Pi’s line-up, the Allwinner H616/H168-equipped 1B feels like it takes hints from both the RPi 4B and the Asus Tinkerboard, especially with its nicely colored GPIO pins. There’s also a beefier Walnut Pi 2B with an Allwinner T527 SoC that’s not being reviewed here. Translating the Chinese-language documentation for the board suggests that either the H616 or H618 may be installed, with both featuring a quad-core Cortex-A53, so in the ballpark of the Raspberry Pi 3.

There are also multiple RAM configurations, ranging from 1 GB of DDR3 to 4 GB of LPDDR4, with the 1 GB version being fun to try and run benchmarks like GeekBench on. Ultimately the impression was that it’s just another Allwinner SoC-based board, with a half-hearted ‘custom’ Linux image, no hardware acceleration due to missing (proprietary) Allwinner IP block drivers, etc.

While cheaper than a Raspberry Pi SBC, if you need anything more than the basic Allwinner H61* support and Ethernet/WiFi, there clearly are better options, some of which may even involve repurposing an e-waste Android TV box.

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Putting A Cheapo 1800W DC-DC Boost Converter To The Test

January 1, 2026 by Maya Posch 16 Comments

These days ready-to-use DC-DC converters are everywhere, with some of the cheaper ones even being safe to use without an immediate risk to life and limb(s). This piques one’s curiosity when browsing various online shopping platforms that are quite literally flooded with e.g. QS-4884CCCV-1800W clones of a DC-DC boost converter. Do they really manage 1800 Watt even without active cooling? Are they perhaps a good deal? These were some of the questions that [Josh] over at the [Signal Drift] channel set out to answer.

The only real ‘datasheet’ for this module seems to come courtesy of a Floridian company who also calls it the 36843-PS, but it features specifications that are repeated across store listings so it might as well by the official ‘datasheet’. This module is marketed as being designed for the charging of lead-acid and similar batteries, including the boosting of PV solar panel outputs, though you’d really want to use an MPPT charger for that.

With this use case in mind, it’s probably no surprise to see on the oscilloscope shots under load that it has a tragic 100 kHz switching frequency and a peak-to-peak noise on the output of somewhere between 1-7 VDC depending on the load. Clearly this output voltage was not meant for delicate electronics.

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The Rise Of Fake Casio Scientific Calculators

December 29, 2025 by Maya Posch 40 Comments

Scientific calculators are an amazing invention that take pocket calculators from being merely basic arithmetic machines to being pocket computers that can handle everything from statistics to algebra. That said, there are a few layers of scientific calculators, starting with those aimed at students. This is where Casio is very popular, especially because it uses traditional algebraic notation (VPAM) that follows the written style, rather than the reverse-polish notation (RPN) of HP and others. However, much like retro Casio wristwatches, it appears that these Casio calculators are now being (poorly) faked, as explained by [Another Roof] on YouTube.

The advanced fx-991 models are updated every few years, with the letters following the model indicating the year, such as fx-991EX standing for the 2015-released model. This was the model that got purchased online and which turned out to be fake. While the fx-991CW is newer, it changes the entire interface and is rightfully scolded in the video. Arguably this makes it the worst Casio scientific calculator in history.

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Testing 8 Solder Flux Pastes After Flux Killed A GeForce2 GTS

December 20, 2025 by Maya Posch 18 Comments

Riesba NC-559-ASM flux being applied. (Credit: Bits und Bolts, YouTube)

Flux is one of those things that you cannot really use too much of during soldering, as it is essential for cleaning the surface and keeping oxygen out, but as [Bits und Bolts] recently found, not all flux is made the same. After ordering the same fake Amtech flux from the same AliExpress store, he found that the latest batch didn’t work quite the same, resulting in a Geforce 2 GTS chip getting cooked while trying to reball the chip with uncooperative flux.

Although it’s easy to put this down to a ‘skill issue’, the subsequent test of eight different flux pastes ordered from both AliExpress and Amazon, including — presumably genuine — Mechanic flux pastes with reballing a section of a BGA chip, showed quite different flux characteristics, as you can see in the video below. Although all of these are fairly tacky flux pastes, with some, the solder balls snapped easily into place and gained a nice sheen afterwards, while others formed bridges and left a pockmarked surface that’s indicative of oxygen getting past the flux barrier.

Not all flux pastes are made the same, which also translates into how easy the flux remnants are to clean up. So-called ‘no clean’ flux pastes are popular, which take little more than some IPA to do the cleaning, rather than specialized PCB cleaners as with the used Mechanic flux. Although the results of these findings are up for debate, it can probably be said that ordering clearly faked brand flux paste is a terrible idea. While the top runner brand Riesba probably doesn’t ring any bells, it might be just a Chinese brand name that doesn’t have a Western presence.

As always, caveat emptor, and be sure to read those product datasheets. If your flux product doesn’t come with a datasheet, that would be your first major red flag. Why do we need flux? Find out.

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