This image created using GPT-4o on Poe using the prompt “picture of an upright freezer connected to a computer for temperature monitoring, together with a graph and an alarm siren. Suitable for a professional blog. Be humorous and use a vintage theme.”

Freezer Monitoring: Because Ice Cream Is A Dish Best Served Cold

July 21, 2025 by 23 Comments

[Scott Baker] wrote in to let us know about his freezer monitor.

After a regrettable incident where the ice cream melted because the freezer failed [Scott] decided that what was called for was a monitoring and alerting system. We enjoyed reading about this hack, and we’ll give you the details in just a tick, but before we do, we wanted to mention [Scott]’s justifications for why he decided to roll his own solution for this, rather than just using the bundled proprietary service from the white goods manufacturer.

We’re always looking for good excuses for rolling our own systems, and [Scott]’s list is comprehensive: no closed-source, no-api cloud service required, can log with high fidelity, unlimited data retention, correlation with other data possible, control over alerting criteria, choice of alerting channels. Sounds fair enough to us!

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Fixing Human Sleep With Air Under Pressure

July 21, 2025 by 68 Comments

By and large, the human body is designed to breathe from birth, and keep breathing continuously until death. Indeed, if breathing stops, lifespan trends relatively rapidly towards zero. There’s a whole chunk of the brain and nervous system dedicated towards ensuring oxygen keeps flowing in and carbon dioxide keeps flowing out.

Unfortunately, the best laid plans of our body often go awry. Obstructive sleep apnea is a condition in which a person’s airways become blocked by the movement of soft tissues in the throat, preventing the individual from breathing. It’s a mechanical problem that also has a mechanical solution—the CPAP machine.

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Don’t Turn That Old System On, First Take It Apart

July 21, 2025 by 35 Comments

When you first get your hands on an old piece of equipment, regardless of whether it’s an old PC or some lab equipment, there is often the temptation to stick a power lead into it and see what the happy electrons make it do. Although often this will work out fine, there are many reasons why this is a terrible idea. As many people have found out by now, you can be met by the wonderful smell of a Rifa capacitor blowing smoke in the power supply, or by fascinatingly dangly damaged power wires, as the [Retro Hack Shack] on YouTube found recently in an old Gateway PC.

Fortunately, this video is a public service announcement and a demonstration of why you should always follow the sage advice of “Don’t turn it on, take it apart”. Inside this Gateway 2000 PC from 1999 lurked a cut audio cable, which wasn’t terribly concerning. The problem was also a Molex connector that had at some point been violently ripped off, leaving exposed wiring inside the case. The connector and the rest of the wiring were still found in the HDD.

Other wires were also damaged, making it clear that the previous owner had tried and failed to remove some connectors, including the front panel I/O wiring. Thankfully, this PC was first torn apart so that the damage could be repaired, but it shows just how easily a ‘quick power-on check’ can turn into something very unpleasant and smelly.

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Why Apple Dumped 2,700 Computers In A Landfill In 1989

July 21, 2025 by 55 Comments

In 1983, the Lisa was supposed to be a barnburner. Apple’s brand-new computer had a cutting edge GUI, a mouse, and power far beyond the 8-bit machines that came before. It looked like nothing else on the market, and had a price tag to match—retailing at $9,995, or the equivalent of over $30,000 today.

It held so much promise. And yet, come 1989, Apple was burying almost 3,000 examples in a landfill. What went wrong?

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3D printed rotary table

Bearing Witness: Measuring The Wobbles In Rotary Build

July 21, 2025 by 5 Comments

3D printing has simplified the creation of many things, but part of making something is knowing just how much you can rely on it. On the [BubsBuilds] YouTube channel, he built a cheap rotary table and then walked through the process of measuring the error inherent in any rotating system.

Starting with a commercial rotary table, [BubsBuilds] decided he wanted a rotary stage that was both lighter and had provisions for motorized movement. Most of the rotary build is 3D printed, with the large housing and table made from PETG, and the geared hub and worm gear printed on a resin printer. The bearings used to support the worm gear are common skateboard bearings. There is also a commercial thrust bearing and 49 larger 9.5 mm ball bearings supporting the rotating tabletop.

There are three different types of runout to be measured on a rotating stage: axial, radial, and angular. Axial runout is fairly straightforward to discern by measuring the vertical variation of the table as it rotates. Radial runout measures how true the rotation is around the center of the table. Angular runout measures how level the table stays throughout its range. Since these two runouts are tied to each other, [BubsBuilds] showed how you can take measurements at two different heights and use trigonometry to obtain both your radial and angular runout

This is a great walk-through of how to approach measuring and characterizing a system that has multiple variables at play. Be sure to check out some of the other cool rotary tables we’ve featured.

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Reverse Engineering A ‘Tony’ 6502-based Mini Arcade Machine

July 21, 2025 by 15 Comments
The mainboard of the mini arcade unit with its blob chip and EEPROM. (Credit: Poking Technology, YouTube)
The mainboard of the mini arcade unit with its blob chip and EEPROM. (Credit: Poking Technology, YouTube)

For some reason, people are really into tiny arcade machines that basically require you to ruin your hands and eyes in order to play on them. That said, unlike the fifty gazillion ‘retro consoles’ that you can buy everywhere, the particular mini arcade machine that [David Given] of [Poking Technology] obtained from AliExpress for a teardown and ROM dump seems to have custom games rather than the typical gaggle of NES games and fifty ROM hack variations of each.

After a bit of gameplay to demonstrate the various games on the very tiny machine with tiny controls and a tiny 1.8″, 160×128 ST7735 LC display, the device was disassembled. Inside is a fairly decent speaker, the IO board for the controls, and the mainboard with an epoxy blob-covered chip and the SPI EEPROM containing the software. Dumping this  XOR ‘encrypted’ ROM was straightforward, revealing it to be a 4 MB, W23X32-compatible EEPROM.

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Researching Glow-Powder Left A Few Scars

July 20, 2025 by 34 Comments

Content warning: Human alteration and scalpels.
General warning: We are not speaking as doctors. Or lawyers.

If you watch sci-fi, you probably do not have to think hard to conjure a scene in a trendy bar where the patrons have glowing make-up or tattoos. That bit of futuristic flair was possible years ago with UV-reactive tattoo ink, but it has the unfortunate tendency to permanently fade faster than traditional ink. [Miana], a biohacker, wanted something that could last forever and glow on its own. After months of research and testing, she presents a technique with a silica-coated powder and scarification. Reddit post with graphic content.

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