Day: March 26, 2025

Why Are Micro Center Flash Drives So Slow?

March 26, 2025 by 45 Comments

Every year, USB flash drives get cheaper and hold more data. Unfortunately, they don’t always get faster. The reality is, many USB 3.0 flash drives aren’t noticeably faster than their USB 2.0 cousins, as [Chase Fournier] found with the ultra-cheap specimens purchased over at his local Micro Center store.

Although these all have USB 3.0 interfaces, they transfer at less than 30 MB/s, but why exactly? After popping open a few of these drives the answer appears to be that they use the old-style Phison controller (PS2251-09-V) and NAND flash packages that you’d expect to find in a USB 2.0 drive.

Across the 32, 64, and 256 GB variants the same Phison controller is used, but the PCB has provisions for both twin TSOP packages or one BGA package. The latter package turned out to be identical to those found in the iPhone 8. Also interesting was that the two 256 GB drives [Chase] bought had different Phison chips, as in one being BGA and the other QFP. Meanwhile some flash drives use eMMC chips, which are significantly faster, as demonstrated in the video.

It would seem that you really do get what you pay for, with $3 “USB 3.0” flash drives providing the advertised storage, but you really need to budget in the extra time that you’ll be waiting for transfers.

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Fitting A Spell Checker Into 64 KB

March 26, 2025 by 16 Comments

By some estimates, the English language contains over a million unique words. This is perhaps overly generous, but even conservative estimates generally put the number at over a hundred thousand. Regardless of where the exact number falls between those two extremes, it’s certainly many more words than could fit in the 64 kB of memory allocated to the spell checking program on some of the first Unix machines. This article by [Abhinav Upadhyay] takes a deep dive on how the early Unix engineers accomplished the feat despite the extreme limitations of the computers they were working with.

Perhaps the most obvious way to build a spell checker is by simply looking up each word in a dictionary. With modern hardware this wouldn’t be too hard, but disks in the ’70s were extremely slow and expensive. To move the dictionary into memory it was first whittled down to around 25,000 words by various methods, including using an algorithm to remove all affixes, and then using a Bloom filter to perform the lookups. The team found that this wasn’t a big enough dictionary size, and had to change strategies to expand the number of words the spell checker could check. Hash compression was used at first, followed by hash differences and then a special compression method which achieved an almost theoretically perfect compression.

Although most computers that run spell checkers today have much more memory as well as disks which are orders of magnitude larger and faster, a lot of the innovation made by this early Unix team is still relevant for showing how various compression algorithms can be used on data in general. Large language models, for one example, are proving to be the new frontier for text-based data compression.

Integrated BMS Makes Battery Packs Easy

March 26, 2025 by 40 Comments

[Editor’s note: The hacker requested that we remove the image for legal reasons, so it’s blurry now. We hope all’s well!]

Lithium technology has ushered in a new era of batteries with exceptionally high energy density for a reasonably low cost. This has made a lot possible that would have been unheard of even 20 years ago such as electric cars, or laptops that can run all day on a single charge. But like anything there are tradeoffs to using these batteries. They are much more complex to use than something like a lead acid battery, generally requiring a battery management system (BMS) to keep the cells in tip-top shape. Generally these are standalone systems but [CallMeC] integrated this one into the buswork for a battery pack instead.

The BMS is generally intended to make sure that slight chemical imbalances in the battery cells don’t cause the pack to wear out prematurely. They do this by maintaining an electrical connection to each cell in the battery so they can charge them individually when needed, making sure that they are all balanced with each other. This BMS has all of these connections printed onto a PCB, but also included with the PCB is the high-power bus that would normally be taken care of by bus bar or nickel strips. This reduces the complexity of assembling the battery and ensures that any time it’s hooked up to a number of cells, the BMS is instantly ready to go.

Although this specific build is meant for fairly large lithium iron phosphate batteries, this type of design could go a long way towards making quick battery packs out of cells of any type of battery chemistry that typically need a BMS system, from larger 18650 packs or perhaps even larger cells like those out of a Nissan Leaf.

3D-Printed Scanner Automates Deck Management For Trading Card Gamers

March 26, 2025 by 11 Comments

Those who indulge in trading card games know that building the best deck is the key to victory. What exactly that entails is a mystery to us muggles, but keeping track of your cards is a vital part of the process, one that this DIY card scanner (original German; English translation) seeks to automate.

At its heart, [Fraens]’ card scanner is all about paper handling, which is always an engineering task fraught with peril. Cards like those for Magic: The Gathering and other TCGs are meant to be handled by human hands, and automating the task of flipping through them presents some challenges. [Fraens] uses a pair of motorized 3D-printed rollers with O-rings to form a conveyor belt that can pull one card at a time off the bottom of a deck. An adjustable retaining roller made from the most adorable linear bearing we’ve ever seen ensures that only one card at a time is pulled from the hopper onto an imaging platen. An adjustable mount holds a smartphone to take a picture of the card, which is fed into an app that extracts all the details and categorizes the cards in the deck.

Aside from the card handling mechanism, there are some pretty slick details to this build. The first is that [Fraens] noticed that the glossy finish on some cards interfered with scanning, leading him to add a diffused LED ringlight to the rig. If an image isn’t scannable, the light goes through a process of dimming and switching colors until a good scan is achieved. Also, to avoid the need to modify the existing TCG deck management app, [Fraens] added a microphone to the control side of the scanner that listens for the sounds the app makes when it scans cards. And if Magic isn’t your thing, the basic mechanism could easily be modified to scan everything from business cards to old family photos.

Continue reading “3D-Printed Scanner Automates Deck Management For Trading Card Gamers” →

Supercon 2024: A New World Of Full-Color PCBs

March 26, 2025 by 12 Comments

Printed circuit boards were once so simple. One or two layers of copper etched on a rectangular fiberglass substrate, with a few holes drilled in key locations so components could be soldered into place. They were functional objects, nothing more—built only for the sake of the circuit itself.

Fast forward to today, and so much has changed. Boards sprout so many layers, often more than 10, and all kinds of fancy geometric features for purposes both practical and pretty. But what catches they eye more than that, other than rich, saturated color? [Joseph Long] came to the 2024 Hackaday Supercon to educate us on the new world of full color PCBs.

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Teardown Of Casio Credit Card-Sized Radio

March 26, 2025 by 33 Comments

These days we don’t get too fussed about miniaturized electronics, not when you can put an entire processor and analog circuitry on a chip the size of a grain of sand. Things were quite different back in the 1980s, with the idea of a credit card-sized radio almost preposterous. This didn’t stop the engineers over at Casio from having a go at this and many other nutty ideas, with [Matt] from Techmoan having a go at taking one of these miniaturized marvels apart.

The Casio FM Stereo radio in happier days. (Credit: Techmoan, YouTube)

On the chopping block is the FM stereo device that was featured in a previous episode. Out of the four credit card-sized radios in that video, the one with the rechargeable battery (obviously) had ceased to work, so it was the obvious choice for a teardown. This mostly meant peeling off the glued-on top and bottom, after which the circuitry became visible.

In addition to the battery with a heavily corroded contact, the thin PCB contains a grand total of three ICs in addition to the analog circuitry. These were identified by [Spritetm] as an AM/FM tuner system IC (TA7792), an FM PLL MPX (TA7766AF) and a headphone amplifier (TA7767F), all of them manufactured by Toshiba.

Although [Matt] reckons this was a destructive teardown, we’re looking forward to the repair video where a fresh cell is soldered in and the case glued back together. Continue reading “Teardown Of Casio Credit Card-Sized Radio” →