Investigating Electromagnetic Magic In Obsolete Machines

February 5, 2025 by 15 Comments

Before the digital age, when transistors were expensive, unreliable, and/or nonexistent, engineers had to use other tricks to do things that we take for granted nowadays. Motor positioning, for example, wasn’t as straightforward as using a rotary encoder and a microcontroller. There are a few other ways of doing this, though, and [Void Electronics] walks us through an older piece of technology called a synchro (or selsyn) which uses a motor with a special set of windings to keep track of its position and even output that position on a second motor without any digital processing or microcontrollers.

Synchros are electromagnetic devices similar to transformers, where a set of windings induces a voltage on another set, but they also have a movable rotor like an electric motor. When the rotor is energized, the output windings generate voltages corresponding to the rotor’s angle, which are then transmitted to another synchro. This second device, if mechanically free to move, will align its rotor to match the first. Both devices must be powered by the same AC source to maintain phase alignment, ensuring their magnetic fields remain synchronized and their rotors stay in step.

While largely obsolete now, there are a few places where these machines are still in use. One is in places where high reliability or ruggedness is needed, such as instrumentation for airplanes or control systems or for the electric grid and its associated control infrastructure. For more information on how they work, [Al Williams] wrote a detailed article about them a few years ago.

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A Raspberry Pi HAT with retro LED displays and a buttons, sitting on the keys of a laptop.

Good-Looking HAT Does Retro Displays Right

February 5, 2025 by 2 Comments

Mick Jagger famously said that you cain’t always get what you want. But this is Hackaday, and we make what we want or can’t get. Case in point: [Andrew Tudoroi] is drawn to retro LEDs and wanted one of Pimoroni’s micro-LED boards pretty badly, but couldn’t get his hands on one. You know how this ends — with [Andrew] designing his first PCB.

The Pitanga hat is equally inspired by additional fruit that [Andrew] had lying around in the form of an 8devices Rambutan board. (Trust us, it’s a fruit.) With some research, he discovered the HT16K33 LED driver, which checked all the boxen.

Pitanga hats with various cool LED displays.The first version worked, but needed what looks like a couple of bodge wires. No shame in that! For the next revision, [Andrew] added buttons and decided to make it into a Raspberry Pi HAT.

This HAT is essentially a simple display with a basic input device, and a beauty at that. You can see all the various cool displays that [Andrew] tried both here and in the project log. Although he included pads for an ARM M0 microcontroller, he never did populate it. Maybe in the future.

Of course, this project was not without its challenges. For one thing, there was power compatibility to wrestle with. The Pi can sometimes work with I²C devices at 5 V, but this isn’t ideal long-term. So [Andrew] put the LED driver on the 3.3 V I²C bus. Despite the data sheet calling for 4.5 to 5.5 V, the setup worked fine. But for better reliability, [Andrew] threw a dedicated I²C logic level converter chip into the mix.

Don’t forget, you can run a noble amassment of HATs with the PiSquare.

Sleeping arctic fox (Alopex lagopus). (Credit: Rama, Wikimedia)

Investigating Why Animals Sleep: From Memory Sorting To Waste Disposal

February 5, 2025 by 20 Comments

What has puzzled researchers and philosophers for many centuries is the ‘why’ of sleep, along with the ‘how’. We human animals know from experience that we need to sleep, and that the longer we go without it, the worse we feel. Chronic sleep-deprivation is known to be even fatal. Yet exactly why do we need sleep? To rest our bodies, and our brains? To sort through a day’s worth of memories? To cleanse our brain of waste products that collect as neurons and supporting cells busily do their thing?

Within the kingdom of Animalia one constant is that its brain-enabled species need to give these brains a regular break and have a good sleep. Although what ‘sleep’ entails here can differ significantly between species, generally it means a period of physical inactivity where the animal’s brain patterns change significantly with slower brainwaves. The occurrence of so-called rapid eye movement (REM) phases is also common, with dreaming quite possibly also being a feature among many animals, though obviously hard to ascertain.

Most recently strong evidence has arisen for sleep being essential to remove waste products, in the form of so-called glymphatic clearance. This is akin to lymphatic waste removal in other tissues, while our brains curiously enough lack a lymphatic system. So is sleeping just to a way to scrub our brains clean of waste?

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Hacking The 22€ BLE SR08 Smart Ring With Built-In Display

February 5, 2025 by 28 Comments

In the process of making everything ‘smart’, it would seem that rings have become the next target, and they keep getting new features. The ring that [Aaron Christophel] got his mittens on is the SR08, which appears to have been cloned by many manufacturers at this point. It’s got an OLED display, 1 MB Flash and a Renesas DA14585 powering it from a positively adorable 16 mAh LiPo battery.

The small scale makes it an absolute chore to reverse-engineer and develop with, which is why [Aaron] got the €35 DA14585 development kit from Renesas. Since this dev kit only comes with a 256 kB SPI Flash chip, he had to replace it with a 1 MB one. The reference PDFs, pinouts and custom demo firmware are provided on his GitHub account, all of which is also explained in the video.

Rather than hack the ring and destroy it like his first attempts, [Aaron] switched to using the Renesas Software Update OTA app to flash custom firmware instead. A CRC error is shown, but this can be safely ignored. The ring uses about 18 µA idle and 3 mA while driving the display, which is covered in the provided custom firmware for anyone who wants to try doing something interesting with these rings.

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What Happens If You Die In Space?

February 5, 2025 by 51 Comments

There are no two ways about it—space will kill you if you give it half a chance. More than land, sea, or air, the space environment is entirely hostile to human existence. Precision-engineered craft are the bare minimum just to ensure human survival. Even still, between the vacuum, radiation, micrometeorites, and equipment failures, there are plenty of ways for things to go catastrophically wrong beyond Earth’s atmosphere.

Despite the hazards, most spacefaring humans have completed their missions without injury. However, as we look to return to the Moon, tread on Mars, and beyond, it’s increasingly likely that future astronauts could pass away during longer missions. When that inevitably happens, the question is simple—how do you deal with death in space?

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Breaking: USPS Halts Inbound Packages From China And Hong Kong Posts

February 5, 2025 by 104 Comments

Update: The USPS has now resumed acceptance of inbound packages from China. According to the updated Service Alert, they are currently working with Customs and Border Protection to “implement an efficient collection mechanism for the new China tariffs.’

Some troubling news hit overnight as the United States Post Office announced via a terse “Service Alert” that they would suspend acceptance of inbound parcels from China and Hong Kong Posts, effective immediately.

The Alert calls it a temporary suspension, but gives no timeline on when service will be restored. While details are still coming together, it seems likely that this suspension is part of the Trump administration’s Chinese tariff package, which went into effect at midnight.

Specifically, the administration looks to close the “de minimis” exemption — a loophole which allowed packages valued under $800 USD to pass through customs without having to pay any duties or fees. Those packages will now not only be subject to the overall 10% tax imposed by the new tariff package, but will now have to be formally processed through customs, potentially tacking on even more taxes and fees.

The end result is that not only will your next order of parts from AliExpress be more expensive, but it’s likely to take even longer to arrive at your door. Of course, this should come as no surprise. At the end of the day, this is precisely what the administration aims to accomplish with the new tariffs — if purchasing goods from overseas is suddenly a less attractive option than it was previously, it will be a boon to domestic suppliers. That said, some components will be imported from China regardless of who you order them from, so those prices are still going to increase.

Other carriers such as FedEx and UPS will also have to follow these new rules, but at the time of this writing, neither service had released a statement about how they intend to comply.