Behold A Microscope That Sees By Squashing Things Into It

February 5, 2023 by 18 Comments

“Look with your eyes, not your hands” is something many of us have heard while growing up, but that doesn’t apply to the touch-sensitive microscope [Steve Mould] got to play with.

Gel pad removed, exposing lens and multi-directional lighting.

The wand-like device is made by Gelsight, and instead of an optical lens like a normal microscope, it sports a gel pad on the sensing end. By squashing an object into the gel, the device is able to carefully illuminate and image the impression created. By taking multiple images lit from different angles, a lot of information can be extracted.

The result is a high-resolution magnification — albeit a monochromatic one — that conveys depth extremely well. It’s pretty neat clearly seeing tiny specks of dust or lint present on surfaces when [Steve] demonstrates imaging things like coin cells.

Many a hacker knows that the devil is in the details when it comes to executing an idea. Even so, the basic principles of the Gelsight seem simple enough and possibly within the realm of inspired DIY in the same way that we saw a CNC gantry and USB microscope repurposed as an optical comparator.

Watch the Gelsight in action in the video below, embedded below the page break.

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Dishwasher Repair Nightmare: Chasing Down 3 Faults

February 5, 2023 by 42 Comments

It all started with a vague error code (shown in the image above) on [nophead]’s Bosch SMS88TW01G/01 dishwasher, and it touched off a months-long repair nightmare that even involved a logic analyzer. [nophead] is normally able to handily diagnose and repair electronic appliances, but this time he had no idea what he was in for.

Not many dishwashers require breaking out a logic analyzer and 3D-printed custom adapters, but this one did.

Not only were three separate and unrelated faults at play (one of them misrepresented as a communications error that caused a lot of head-scratching) but to top it all off, the machine is just not very repair-friendly. The Bosch device utilized components which are not easily accessible. In the end [nophead] prevailed, but it truly was a nightmare repair of the highest order. So what went wrong?

One error appears to have been due to a manufacturing problem. While reverse-engineering the electronics in the appliance, [nophead] noticed a surface-mounted transistor that looked crooked. It was loose to the touch and fell into pieces when he attempted to desolder it. This part was responsible for switching an optical sensor, so that was one problem solved.

Another issue was a “communications error”. This actually came down to ground leakage due to a corroded and faulty heater, and to say that it was a pain to access is an understatement. Accessing this part requires the machine to be turned upside down, because the only way to get to it is by removing the base of the dishwasher, which itself requires a bizarre series of awkward and unintuitive steps to remove. Oh, and prior to turning the machine upside down, one has to purge the sump pump, which required a 3D-printed adapter… and the list goes on.

And the E02 error code, the thing that started it all? This was solved early in troubleshooting by changing a resistor value by a tiny amount. [nophead] is perfectly aware that this fix makes no sense, but perhaps it was in fact related to the ground leakage problem caused by the corroded heater. It may return to haunt the future, but in the meantime, the machine seems happy.

It goes to show that even though every fault has a cause and a reason, sometimes they are far from clear or accessible, and the road to repair is just a long slog. Heck, even phones these days can be bricked by accidentally swapping a 1.3 mm screw for a 1.2 mm screw.

Dumping script window, showing the bytes being dumped one by one from the STM chip

Need To Dump A Protected STM32F0x? Use Your Pico!

February 5, 2023 by 21 Comments

Sometimes, security mechanisms can be bypassed if you just do things slightly out of the ordinary. For instance, readout protection on microcontrollers is a given nowadays, to the point where it’s intentionally enabled and relied upon as a major technical measure to protect intellectual property. The gist is — when you connect to a microcontroller over its debug interface and then ask to read its flash memory, it will politely refuse. However, [Racerxdl] shows us that in practice, it’s not flawless protection – for certain chips, you just need to be a little quicker than usual.

Usually, flashing and debugging software will chat with the microcontroller for a bit, and probe parameters before going for any direct requests. However, if you skip the courtesy and bluntly get to the point immediately right after power is applied to the microcontroller, you can intimidate them just enough to give you one byte of its memory before it refuses to cooperate further. Since that can be any byte you wish, you can read the entire flash — one byte at a time.

You need to power cycle the chip before you can progress, so the hardware does involve a bit more than just an SWD interface, and it will take a fair bit more time than reading out a non-protected chip the usual way; plus, of course, the debugging interface needs to be active for this in the first place, which isn’t always the case. However, it still beats paying a few thousand dollars for a factory in China to decap your chip and read it out using a fancy machine.

[Racerxdl] didn’t just write a proof-of-concept for this attack – they implemented it for one of our favourite chips, the RP2040. As such, you no longer need an unobtainium STM32 to dump an unobtainium STM32.

To be clear, [Racerxdl] didn’t design this attack — it’s been around for some time now. Credit for that goes to Johanes Obermaier. All in all, this is a wonderful reminder that seemingly reliable security mechanisms can be foiled by the simplest tricks. For instance, if your chip erases the flash when you unlock its protection, you can just tell it not to.

The Effect Of Filament Color On Print Strength And More

February 5, 2023 by 16 Comments

What is an FDM filament coloring’s purpose but to be an aesthetic choice? As it turns out, the additives that create these changes in coloring and transparency also affect the base properties of the polymer, whether it’s PLA, PETG, or another material. This is where a recent video by [CNC Kitchen] is rather illustrative, using a collection of colored PLA filaments from a single filament manufacturer.

[CNC Kitchen] ran a range of tests including tensile strength, ductility, layer adhesion, impact resistance, and annealing performance. The results showed no clear overall winner between plain PLA polymer and any specific color. Perhaps most fascinating was just how much these color additives change the material’s response to annealing. Baking the PLA at 100°C for 30 minutes generally improves material properties, but also can cause warping and shrinking. The effective warping and shrinking differed wildly between the filament.

The general conclusion would seem to be that the natural polymer isn’t necessarily the optimal choice, but that you should test and pick the filament from a specific manufacturer to fit your project’s needs.

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Sundial Collection Is 2D Printed

February 5, 2023 by 3 Comments

We see a lot of clocks, and many of the better ones have some 3D printed elements to them. But [Carl Sabanski] shows us his kits for making sundials for either hemisphere using a conventional printer (you know, one that puts ink on paper), some styrofoam, and possibly some other materials like wire coat hangers, threaded rods, thumbtacks, glue, and different papers like transparencies or card stock.

In all, there are 21 different kinds of sundials. Some are pretty standard-looking fare, but there are others, like the pinwheel equatorial sundial or the cycloid polar sundial, which might be surprising. One even uses a CD as a kind of indicator.

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3 Ways To DIY Custom CNC Dust Covers

February 4, 2023 by 6 Comments

Home shop machinists know dust shields are important for keeping swarf out of expensive linear rails and ball screws. [Petteri Aimonen] demonstrates three inexpensive ways to DIY some bellows-style dust covers. Such things can of course be purchased, but they’re priced at a premium and not always available in the size one needs.

A bellows-style dust cover ideally maximizes extension length while minimizing side wall distortion. It should hold its shape without external support.

The first method is to fold a suitable flat plastic or paper sheet into a bellows pattern. This method is all about the fold pattern, and thankfully, there’s no need to reinvent the wheel. [Petteri] used a fellow enthusiast’s bellows folding pattern generator which is, believe it or not, itself inspired by a remarkably comprehensive US Patent Number 6,054,194.

The downside to this method is the thickness of the bellows when it is fully collapsed. The corners always contain the most material, because it is there that the material is folded upon itself, and this limits how close to the end of travel the CNC carriage can move with the bellows attached.

The second method is to cut a large number of C-shaped sections from fabric and sew them together to make bellows. This method collapses down well and holds its shape well, but the cutting and sewing it requires can be a barrier.

The final method — and the one [Petteri] found most useful — was to hack some IKEA window blinds. IKEA Schottis pleated blinds are inexpensive, with a slick finish on one side and polyester fabric.  The polyester is perfect for gluing. By cutting the material at a 45-degree angle into three sections and gluing them into a U-shape, one can create a serviceable bellows-style cover for a minimum of work.

Any of the explored methods can do the job, but [Petteri] has formulas to determine the maximum extensions and folded thicknesses of each method just in case one would like to see for themselves before choosing. And if a bellows-style cover isn’t your cup of tea, check out this method for turning a plastic strip into a spring-like tube that does the same job.

Reliving A Bitmapped Past With A Veritable Hoard Of Bitmap Fonts

February 4, 2023 by 12 Comments

The fonts seen with old computer systems such as those from Apple and Commodore, as well as Microsoft Windows 3.1 and older, form an integral part of our interaction with these systems. These days such bitmap fonts are a rarity, with scalable vector-based fonts having taken their place on modern-day systems. This unfortunately also means that these fonts are at major risk of being lost to the sands of time. This is where [Rob Hagemans] seeks to maintain an archive of such bitmap fonts, ranging from Acorn to MSX to Windows.

Many of these fonts are extracted from character ROMs, with a preview of some of these fonts available via the Monobit viewer. The fonts themselves are made available in YAFF format, which is a text-based format that can be converted back to a binary format using the Monobit tool. If you ever wanted to use one of these old bitmap fonts in a project, this would seem to offer a treasure trove of options. The hoard of bitmap fonts might be the perfect fit for your next graphic LCD project.

(Via [SuperIlu] on Mastodon)