How Different Are SpaceX Thermal Tiles From The Space Shuttle’s?

February 14, 2024 by Maya Posch 9 Comments

When SpaceX first showed off the thermal tiles on its Starship spacecraft that should keep it safe when re-entering the Earth’s atmosphere towards the loving embrace of the chopsticks on the launch tower, some similarity to the thermal tiles on NASA’s now retired Space Shuttle Orbiter was hard to miss.

Electron microscope image of the fibrous part of a Starship thermal tile, showing very large fibers. (Credit: Breaking Taps, YouTube)

Yet how similar are they really? That’s what the [Breaking Taps] channel on YouTube sought to find out, using an eBay-purchased chunk of Shuttle thermal tile along with bits of Starship tiles that washed ashore following the explosive end to the vehicle’s first integrated test last year.

To answer the basic question: the SpaceX engineers responsible for the Starship thermal tiles seem to have done their homework. An analysis of not only the structure of the fibrous material, but also the black IR-blocking coating, shows that the Starship tiles are highly reminiscent of the EATB (introduced in 1996) tiles with TUFI (toughened unipiece fibrous insulation) coatings with added molybdenum disilicide, which were used during the last years of the Shuttle program.

TUFI is less fragile than the older RCG (reaction cured glass) coating, but also heavier, which is why few TUFI tiles were used on the Shuttles due to weight concerns. An oddity with the Starship tiles is that they incorporate many very large fibers, which could be by design, or indicative of something else.

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Apple Pushes Back On Right To Repair Bill Due To Parts Pairing

February 14, 2024 by Maya Posch 66 Comments

After previously supporting one in California, Apple has made an about-face and is now pushing back against a “Right to Repair” bill (Senate Bill 1596) currently under consideration in Oregon. The reason for this appears to be due to this new bill making parts pairing illegal, as reported by [404media] and [PCMag].

The practice of parts pairing is becoming ever more prevalent with Apple devices, which links specific parts of a system such as cameras, displays, batteries, and fingerprint sensors to the mainboard. During the open hearing on the newly proposed Oregonian bill, Apple’s [John Perry] insisted that this parts pairing is done for user security, safety and privacy.

Even in we take that claim at face value, the fact remains that with parts pairing in place, only authorized Apple repair centers can routinely replace components — while user repairs are limited to specific devices with limited part availability. Even in the latter case the user still has to contact Apple to have them reauthorize the replaced part. This is becoming an issue with Apple’s MacBooks as well, where the lid angle sensor requires calibration using a proprietary tool.

During the same hearing, the director of an Oregon nonprofit organization noted that of the 15,000 iPhones which they had donated to them last year, only 300 could be refurbished due to parts pairing. The remainder of otherwise perfectly fine phones are discarded for recycling, which is terrible for everyone but Apple. Whether the parts pairing element of the bill survives it to the final form remains to be seen, but if it passes it’d set the trend for future bills in other states as well as amendments to existing ones.

Thanks to [paulvdh] for the tip.

A Clock Made Out Of Electromechanical Relays

February 13, 2024 by Maya Posch 11 Comments

Electromechanical circuits using relays are mostly a lost art these days, but sometimes you get people like [Aart] who can’t resist to turn a stack of clackity-clack relays into a functional design, like in this case a clock (article in Dutch, Google Translate).

It was made using components that [Aart] had come in possession of over the years, with each salvaged part requiring the usual removal of old solder, before being mounted on prototype boards. The resulting design uses the 1 Hz time signal from a Hörz DCF77 master clock which he set up to drive a clock network in his house, as he describes in a forum post at Circuits Online (also in Dutch).

The digital pulses from this time signal are used by the relay network to create the minutes and hours count, which are read out via a resistor ladder made using 0.1% resistors that drive two analog meters, one for the minutes and the other for the hours.

Sadly, [Aart] did not draw up a schematic yet, and there are a few issues he would like to resolve regarding the meter indicators that will be put in front of the analog dials. These currently have weird transitions between sections on the hour side, and the 59 – 00 transition on the minute dial happens in the middle of the scale. But as [Aart] says, this gives the meter its own character, which is an assessment that is hard to argue with.

Thanks to [Lucas] for the tip.

Piezo Transducers Could Turn Displays Into Speakers

February 13, 2024 by Maya Posch 28 Comments

Will piezoelectric-based speakers replace traditional speakers over the coming years in space-constrained devices? We have definitely seen the use of piezo transducers in e.g. high-end televisions that use the display’s surface not just for the visual content, but also as a highly dynamic speaker. If you extrapolate this principle to something like smartphones, tablets and laptops the advantages are clear: piezoelectric transducers are smaller, more power efficient and do not need any holes in the enclosure. These and other advantages are what [Vineet Ganju] argues in IEEE Spectrum will push the market to adopt this new technology.

When piezoelectric transducers vibrate the display itself to create sound waves, the sound seems to come directly from the image on the screen, a much more realistic effect. (Credit: James Provost) — Piezoelectric transducers vibrate the display itself to create sound waves. (Credit: James Provost)

[Vineet] is the Vice President and General Manager of the audio business unit of Synaptics — which is one of the companies pushing for these piezoelectric transducers to be used for speaker purposes — so there is definitely some bias involved. Even so, it’s undeniable that the speakers in portable devices as well as the average flat panel TV aren’t exactly amazing, with the limited space meaning that audio quality suffers, with lows being generally absent and the resulting audio sounding ‘tinny’. Generally this is where people get external speakers for their TV, and lug portable speakers along with their laptop and other mobile devices.

For TVs, Sony has pushed for its Acoustic Surface Audio technology that uses two or three piezoelectric transducers on their OLED panels, while Samsung sticks to traditional speakers, but places lots of them around the screen with its Object Tracking Sound technology.

Sony’s technology cannot be used with LCD panels, due to the backlight being in the way, so the interesting question here is whether the piezoelectric speaker revolution proposed by [Vineet] will be limited to devices that use OLED or similar backlight-less displays?

Understanding Deep Learning: Free MIT Press EBook For Instructors And Students

February 12, 2024 by Maya Posch 9 Comments

The recently published book Understanding Deep Learning by [Simon J. D. Prince] is notable not only for focusing primarily on the concepts behind Deep Learning — which should make it highly accessible to most — but also in that it can be either purchased as a hardcover from MIT Press or downloaded for free from the Understanding Deep Learning website. If you intend to use it for coursework, a separate instructor answer booklet and other resources can be purchased, but student resources like Python notebooks are also freely available. In the book’s preface, the author invites readers to send feedback whenever they find an issue.

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3D Printing Functional Human Brain Tissue For Research Purposes

February 12, 2024 by Maya Posch 18 Comments

Graphical summary of the newly developed 3D bioprinting process. (Credit: Yan et al., 2024)

The brain is probably the least explored organ, much of which is due to the difficulty of studying it in situ rather than in slices under a microscope. Even growing small organoids out of neurons provide few clues, as this is not how brain tissue is normally organized. A possible breakthrough may have been found here by a group of researchers whose article in Cell Stem Cell details how they created functional human neural tissues using a commercial 3D bioprinter.

As detailed by [Yuanwei Yan] and colleagues in their research article, the issue with previous approaches was that although these would print layers of neurons, they would fail to integrate as in the brain. In the brain’s tissues, we see a wide variety of neurons and supportive cells, all of which integrate in a specific way to form functioning neuron-to-neuron and neuron-to-glial connections with expected neural activity. The accomplishment of this research team is 3D bioprinting of neural tissues with the necessary functional connections.

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EasyThreed K9: The Value In A €72 AliExpress FDM 3D Printer

February 12, 2024 by Maya Posch 27 Comments

The hot end of the EasyThreed K9 is actually pretty nifty. (Credit: [Thomas Sanladerer])

Recently, [Thomas Sanladerer] bought an EasyThreed K9 off AliExpress for a mere €72, netting him an FDM printer with a 10 x 10 x 10 cm build volume. The build plate is unheated, with optional upgrade, and there is no display to interact with the device: just a big multi-function ‘play’ button and five smaller buttons that direct the print head to preset locations above the build plate to allow for build plate leveling using the knobs on each corner. There’s also a ‘home’ button on the back for homing the print head, which pretty much completes the user interface. As the printer comes in a rather small box, the first step is to assemble the parts into something resembling a 3D printer.

What follows is both a mixture of wonder and horror, as the plastic build quality is everything but convincing, while at the same time, the self-contained nature of each of the three axes of the cantilevered design makes for very easy assembly. The print head has a nifty flip-up cover for easy access to the hot end, which makes the best of the anemic 24-watt power supply for the entire printer. A cooling fan with an air duct even provides part cooling, making this print head a contender for the ‘cheap but not terrible’ category. You can check out his full video review below.

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