Testing 8 Solder Flux Pastes After Flux Killed A GeForce2 GTS

December 20, 2025 by Maya Posch 14 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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Decapsulating A PIC12F683 To Examine Its CMOS Implementation

December 19, 2025 by John Elliot V 8 Comments

In a recent video, [Andrew Zonenberg] takes us through the process of decapsulating a PIC12F683 to take a peek at its CMOS implementation.

This is a multipart series with five parts done and more to come. The PIC12F683 is an 8-pin flash-based, 8-bit microcontroller from Microchip. [Andrew] picked the PIC12F683 for decapsulation because back in 2011 it was the first microcontroller he broke read-protection on and he wanted to go back and revisit this chip, given particularly that his resources and skills had advanced in the intervening period.

The five videos are a tour de force. He begins by taking a package cross section, then decapsulating and delayering. He collects high-resolution photos as he goes along. In the process, he takes some time to explain the dangers of working with acid and the risk mitigations he has in place. Then he does what he calls a “floorplan analysis” which takes stock of the entire chip before taking a close look at the SRAM implementation.

If you’re interested in decapsulating integrated circuits you might want to take a look at Laser Fault Injection, Now With Optional Decapping, A Particularly Festive Chip Decapping, or even read through the transcript of the Decapping Components Hack Chat With John McMaster.

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Bare Metal STM32: Increasing The System Clock And Running Dhrystone

December 18, 2025 by Maya Posch 9 Comments

When you start an STM32 MCU with its default configuration, its CPU will tick along at a leisurely number of cycles on the order of 8 to 16 MHz, using the high-speed internal (HSI) clock source as a safe default to bootstrap from. After this phase, we are free to go wild with the system clock, as well as the various clock sources that are available beyond the HSI.

Increasing the system clock doesn’t just affect the CPU either, but also affects the MCU’s internal buses via its prescalers and with it the peripherals like timers on that bus. Hence it’s essential to understand the clock fabric of the target MCU. This article will focus on the general case of increasing the system clock on an STM32F103 MCU from the default to the maximum rated clock speed using the relevant registers, taking into account aspects like Flash wait states and the APB and AHB prescalers.

Although the Dhrystone benchmark is rather old-fashioned now, it’ll be used to demonstrate the difference that a faster CPU makes, as well as how complex accurately benchmarking is. Plus it’s just interesting to get an idea of how a lowly Cortex-M3 based MCU compares to a once top-of-the line Intel Pentium 90 CPU.

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Tearing Down Walmart’s $12 Keychain Camera

December 15, 2025 by Lewin Day 45 Comments

Keychain cameras are rarely good. However, in the case of Walmart’s current offering, it might be worse than it’s supposed to be. [FoxTailWhipz] bought the Vivitar-branded device and set about investigating its claim that it could deliver high-resolution photos.

The Vivatar Retro Keychain Camera costs $12.88, and wears “FULL HD” and “14MP” branding on the packaging. It’s actually built by Sakar International, a company that manufactures products for other brands to license. Outside of the branding, though, [FoxTailWhipz] figured the resolution claims were likely misleading. Taking photos quickly showed this was the case, as whatever setting was used, the photos would always come out at 640 x 480, or roughly 0.3 megapixels. He thus decided a teardown would be the best way to determine what was going on inside. You can see it all in the video below.

Pulling the device apart was easy, revealing that the screen and battery are simply attached to the PCB with double-sided tape. With the board removed from the case, the sensor and lens module are visible, with the model number printed on the flex cable. The sensor datasheet tells you what you need to know. It’s a 2-megapixel sensor, capable of resolutions up to 1632 x 1212. The camera firmware itself seems to not even use the full resolution, since it only outputs images at 640 x 480.

It’s not that surprising that an ultra-cheap keychain camera doesn’t meet the outrageous specs on the box. At the same time, it’s sad to see major retailers selling products that can’t do what they say on the tin. We see this problem a lot, in everything from network cables to oscilloscopes.

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Hackaday Links: December 14, 2025

December 14, 2025 by Dan Maloney 7 Comments

Fix stuff, earn big awards? Maybe, if this idea for repair bounties takes off. The group is dubbed the FULU Foundation, for “Freedom from Unethical Limitations on Users,” and was co-founded by right-to-repair activist Kevin O’Reilly and perennial Big Tech thorn-in-the-side Louis Rossman. The operating model works a bit like the bug bounty system, but in reverse: FULU posts cash bounties on consumer-hostile products, like refrigerators that DRM their water filters or bricked thermostats. The bounty starts at $10,000, but can increase based on donations from the public. FULU will match those donations up to $10,000, potentially making a very rich pot for the person or team that fixes the problem.

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Amiibo Emulator Becomes Pocket 2.4 GHz Spectrum Analyzer

December 11, 2025 by Matt Varian 11 Comments

As technology marches on, gear that once required expensive lab equipment is now showing up in devices you can buy for less than a nice dinner. A case in point: those tiny displays originally sold as Nintendo amiibo emulators. Thanks to [ATC1441], one of these pocket-sized gadgets has been transformed into 2.4 GHz spectrum analyzer.

These emulators are built around the Nordic nRF52832 SoC, the same chip found in tons of low-power Bluetooth devices, and most versions come with either a small LCD or OLED screen plus a coin cell or rechargeable LiPo. Because they all share the same core silicon, [ATC1441]’s hack works across a wide range of models. Don’t expect lab-grade performance; the analyzer only covers the range the Bluetooth chip inside supports. But that’s exactly where Wi-Fi, Bluetooth, Zigbee, and a dozen other protocols fight for bandwidth, so it’s perfect for spotting crowded channels and picking the least congested one.

Flashing the custom firmware is dead simple: put the device into DFU mode, drag over the .zip file, and you’re done. All the files, instructions, and source are up on [ATC1441]’s PixlAnlyzer GitHub repo. Check out some of the other amiibo hacks we’ve featured as well.

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PCB Design Review: TinySparrow, A Module For CAN Hacking, V2

December 9, 2025 by Arya Voronova 12 Comments

A year ago, I’ve design reviewed an MCU module for CAN hacking, called TinySparrow. Modules are plenty cool, and even more so when they’re intended for remaking car ECUs. For a while now, every car has heavily depended on a computer to control the operation of everything inside it – the engine and its infrastructure, the lights, and Sadly, ECUs are quite non-hackable, so building your own ECUs only makes sense – which is why it’s heartwarming to see modules intended to make this easier on the budding ECU designer!

Last time we saw this module, it was quite a bit simpler. We talked about fixing a number of things – the linear regulator, the unprotected CAN transceiver, and the pinout; we also made the board cheaper to produce by reducing the layer count and instead pushing the clearance/track width limits. This time, we’re seeing TinySparrow v2 , redesigned accounting for the feedback and upgraded with a new MCU – it’s quite a bit more powerful!

For a start, it’s got ESD diodes, a switching-linear regulator chain for clean but efficient power supply, and most importantly, an upgraded MCU, now with USB and one more CAN channel for a total of two! There’s a lot more GPIOs to go around, too, so the PCB now uses all four of its sides for breakout out power, programming, and GPIO pads. Only a tiny bit bigger than its v1, this module packs a fair bit of punch.

Let’s revisit the design, and try to find anything still left to improve – there’s a few noteworthy things I found.

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