TDS 744A Scope Teardown Fixes Dodgy Channel

June 13, 2024 by Maya Posch 1 Comment

There are a lot of oscilloscopes from around the 1990s which are still very much desirable today, such as the Tektronix TDS 744A which [DiodesGoneWild] got his grubby mitts on. This is a 500 MHz, 4-channel scope, with a capture rate of 500 MS/s (4 channels) to 2 GS/s (1 channel). It also has a color display and even comes with a high-density (1.44 MB) floppy drive. Unfortunately this particular unit was having trouble with its fourth channel, and its NuColor display had degraded, something that’s all too common with this type of hybrid CRT/LCD (LCCS) technology.

Starting with a teardown of the unit to inspect the guts, there was no obvious damage on the PCBs, nor on the acquisition board which would explain the weird DC offset on the fourth channel. After cleaning and inspecting the capture module and putting the unit back together, the bias seen on channel four seemed to disappear. A reminder that the best problems are the ones that solve themselves. As for the NuColor display, this uses a monochrome CRT (which works fine) and an LCD with color filters. It’s the latter which seems degraded on this unit, with a repair still being planned.

We covered NuColor-based devices before, which offer super-sharp details that are hard to capture even with modern-day LCDs, never mind the ones of the 90s. Fixing these NuColor displays can be easy-ish sometimes, as [JVG] found when tearing apart a very similar Tektronix TDX-524A which required a power supply fix and the removal of goopy gel between the CRT and LCD to restore it.

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From Nissan ICE Pickup To BEV With Nissan Leaf Heart

June 11, 2024 by Maya Posch 8 Comments

Last year [Jimmy] got a request from a customer ([Dave]) to help convert a 1998 Nissan Frontier pickup into an electric drive vehicle, with a crashed 2019 Nissan Leaf providing the battery and electric motor for the conversion. He has documented the months-long journey with plenty of photos, as well as a series of videos over at the [EVSwap Conversions] YouTube channel. While the idea sounds easy enough, there’s a lot more to it than swapping out the ICE with an electric motor and sticking some batteries to the bottom of the car somewhere with double-sided tape. The pickup truck got effectively stripped down and gutted, before the 110 kW (150 HP) motor got installed using an adapter plate.

The donor Leaf’s battery pack came in at a decently sized 40 kWh, which should give the converted Nissan Frontier BEV a range of easily 100 miles. This pack was split up into two packs, which got put into a custom aluminium battery box, each mounted on one side of the driveshaft. The charging port got installed on the front of the car, next to the logo, discreetly behind a panel. The front of the car had much of the openings that were needed for the ICE’s radiator sealed up for reduced air friction, along with the new low-friction tires that got installed. Although this converted car still has a radiator, it only needs to assisting cooling the motor stack (including inverter and charger) when driving slowly or charging, making it far less demanding and thus allows for a more sleek front.

As a bonus, the car still has the manual 5-gear shift, just without a clutch, and the pickup bed can now also tilt, albeit with hydraulics (so far). Considering that it started with a decent 1998 pickup and totaled Nissan Leaf, this is among the cleanest conversions we have seen, not to mention a good use of a crashed BEV.

Thanks to [JohnU] for the tip.

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EMO: Alibaba’s Diffusion Model-Based Talking Portrait Generator

June 10, 2024 by Maya Posch 20 Comments

Alibaba’s EMO (or Emote Portrait Alive) framework is a recent entry in a series of attempts to generate a talking head using existing audio (spoken word or vocal audio) and a reference portrait image as inputs. At its core it uses a diffusion model that is trained on 250 hours of video footage and over 150 million images. But unlike previous attempts, it adds what the researchers call a speed controller and a face region controller. These serve to stabilize the generated frames, along with an additional module to stop the diffusion model from outputting frames that feature a result too distinct from the reference image used as input.

In the related paper by [Linrui Tian] and colleagues a number of comparisons are shown between EMO and other frameworks, claiming significant improvements over these. A number of examples of talking and singing heads generated using this framework are provided by the researchers, which gives some idea of what are probably the ‘best case’ outputs. With some examples, like [Leslie Cheung Kwok Wing] singing ‘Unconditional‘ big glitches are obvious and there’s a definite mismatch between the vocal track and facial motions. Despite this, it’s quite impressive, especially with fairly realistic movement of the head including blinking of the eyes.

Meanwhile some seem extremely impressed, such as in a recent video by [Matthew Berman] on EMO where he states that Alibaba releasing this framework to the public might be ‘too dangerous’. The level-headed folks over at PetaPixel however also note the obvious visual imperfections that are a dead give-away for this kind of generative technology. Much like other diffusion model-based generators, it would seem that EMO is still very much stuck in the uncanny valley, with no clear path to becoming a real human yet.

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Fixing Issues With Knockoff Altera USB Blasters

June 9, 2024 by Maya Posch 14 Comments

One exciting feature of hardware development involving MCUs and FPGAs is that you all too often need specific tools to program them, with [Doug Brown] suffering a price tag aneurysm after checking the cost of an official Altera/Intel USB Blaster (yours for $300) to program a MAX 10 FPGA device with. This led him naturally down the path of exploring alternatives, with the $69 Terasic version rejected for ‘being too expensive’ and opting instead for the Waveshare USB Blaster V2, at a regretful $34. The amazing feature of this USB Blaster clone is that while it works perfectly fine under Windows, it works at most intermittently under Linux.

This led [Doug] down the path of reverse-engineering and diagnosing the problem, ultimately throwing in the towel and downclocking the Altera CPLD inside the adapter after finding that it was running a smidge faster than the usual 6 MHz. This was accomplished initially by wiring in an external MCU as a crude (and inaccurate) clock source, but will be replaced with a 12 MHz oscillator later on. Exactly why the problem only exists on Linux and not on Windows will remain a mystery, with Waveshare support also being clueless.

Undeterred, [Doug] then gambled on a $9 USB Blaster clone (pictured above), which turned out to be not only completely non-functional, but also caused an instant BSOD on Windows, presumably due to the faked FTDI USB functionality tripping up the Windows FTDI driver. This got fixed by flashing custom firmware by [Vladimir Duan] to the WCH CH552G-based board after some modifications shared in a project fork. This variety of clone adapters can have a range of MCUs inside, ranging from this WCH one to STM32 and PIC MCUs, with very similar labels on the case. While cracking one open we had lying around, we found a PIC18 inside, but if you end up with a CH552G-based one, this would appear to fully fix it. Which isn’t bad for the merest fraction of the official adapter.

Thanks to [mip] for the tip.

A Compact Electrohydrodynamic Pump Using Copper And TPU

June 9, 2024 by Maya Posch 21 Comments

Electrohydrodynamics (EHD) involves the dynamics of electrically charged fluids, which effectively means making fluids move using nothing but electric fields, making it an attractive idea for creating a pump out of. This is the topic of a 2023 paper by [Michael Smith] and colleagues in Science, titled “Fiber pumps for wearable fluidic systems”. The ‘fiber pumps’ as they call the EHD pumps in this study are manufactured by twisting two helical, 80 µm thick copper electrodes around a central mandrel, along with TPU (thermoplastic polyurethane) before applying heat. This creates a tube where the two continuous electrodes are in contact with any fluids inside the tube.

For the fluid a dielectric fluid is required to create the ions, which was 3M Novec 7100, a methoxy-fluorocarbon. Because of the used voltage of 8 kV, a high electrical breakdown of the fluid is required. After ionization the required current is relatively low, with power usage reported as 0.9 W/m, with one meter of this pump generating a pressure of up to 100 kilopascals and a flowrate of 55 mL/minute. One major limitation is still that after 6 days of continuous pumping, the copper electrodes are rendered inert due to deposits, requiring the entire system to be rinsed. Among the applications the researchers see artificial muscles and flexible tubing in clothing to cool, heat and provide sensory feedback in VR applications.

While the lack of moving parts as with traditional pumps is nice, the limitations are still pretty severe. What is however interesting about this manufacturing method is that it is available to just about any hobbyist who happens to have some copper wiring, TPU filament and something that could serve as a mandrel lying around.

Thanks to [Aaron Eiche] for the tip.

Oral-B Hopes You Didn’t Use Your $230 Alexa-Enabled Toothbrush

June 8, 2024 by Maya Posch 31 Comments

With companies desperate to keep adding more and more seemingly random features to their products, Oral-B made the logical decision to add Alexa integration to its Oral-B Guide electric toothbrush. Taking it one step beyond just Bluetooth in the toothbrush part, the Guide’s charging base also acted as an Alexa-enabled smart speaker, finally adding the bathroom to the modern, all-connected smart home. Naturally Oral-B killed off the required Oral-B Connect smartphone app earlier this year, leaving Guide owners stranded in the wilderness without any directions. Some of the basics of this shutdown are covered in a recent Ars Technica article.

Amidst the outrage, it’s perhaps good to take a bit more of a nuanced view, as despite various claims, Oral-B did not brick the toothbrush. What owners of this originally USD$230 device are losing is the ability to set up the charging base as an Alexa smart speaker, while the toothbrush is effectively just an Oral-B Genius-series toothbrush with Bluetooth and associated Oral-B app. If you still want to have a waterproof smart speaker listening in while in the bathroom, you’ll have to look elsewhere, it seems. Meanwhile existing customers can contact Oral-B support for assistance, while the lucky few who still have the Connect app installed better hope it doesn’t disconnect, as reconnecting it to the smart speaker seems to be impossible, likely due to services shut down by Oral-B together with the old “oralbconnect.com” domain name.

We recently looked at a WiFi-enabled toothbrush as well, which just shows how far manufacturers of these devices are prepared to go, whether they intend to support it in any meaningful fashion or not.

The End Of BLHeli_32: Long Live AM32?

June 7, 2024 by Maya Posch 11 Comments

An essential part of drones are the Electronic Speed Controller (ESC) which translate the commands from the flight computer into responses by the connected brushless motors (generally BLDCs). As the ESC determines a lot of the performance characteristics of a drone, it has its own firmware, which for (FPV) drones is overwhelmingly BLHeli, specifically the 32-bit version (BLHeli_32). Now the Norwegian company (BLHeli AS) behind this closed source firmware has thrown in the towel, citing illegal use of its firmware by sanctioned countries like Russia for purposes like warfare. This news and its implications are covered in detail in a video by the [Mads Tech] YouTube channel, including the message sent to customers by the company’s lawyer.

So far the GitHub repository is still online, featuring binary images for BLHeli_32, as well as the open source BLHeli (8-bit Atmel/Silabs) firmware and BLHeli_S (multirotor 8-bit Silabs) firmware. Due to the open source nature of these earlier projects forks already exist, such as BlueJay for BLHeli_S, and with the AM32 project there is an open source 32-bit ESC alternative. For 8-bit platforms it would thus seem that even with BLHeli_32 vanishing there is no impact at all, while for 32-bit platforms AM32 seems to be largely a drop-in solution.

Regardless of the reasons behind BLHeli_32 vanishing like this, the community and businesses can now hopefully move their (financial) support over to the AM32 project, making this more of a blip than an outright disaster for those who are into their high-end multicopter drones.

Thanks to [Frank Zhao] for the tip.

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