Day: February 5, 2025

This Thermometer Rules!

February 5, 2025 by 9 Comments

A PCB ruler is a common promotional item, or design exercise. Usually they have some sample outlines and holes as an aid to PCB design, but sometimes they also incorporate some circuitry. [Clovis Fritzen] has given us an ingenious example, in the form of a PCB ruler with a built-in thermometer.

This maybe doesn’t have the fancy seven segment or OLED display you were expecting though, instead it’s an ATtiny85 with a lithium cell, the minimum of components, a thermistor for measurement, and a couple of LEDs that serve as the display. These parts are interesting, because they convey the numbers by flashing. One LED is for the tens and the other the units, so count the flashes and you have it.

We like this display for its simplicity, we can see the same idea could be used in many other places.On a PCB ruler, it certainly stands apart from the usual. It has got plenty of competition though.

A picture of a stainless steel ring with a phillips screwdriver bit protruding from it sitting slightly askance atop a matching ring with a phillips head cut out like that of a screw. They are the same size so they can mesh when placed together.

Making Products For Fun And (Probably No) Profit

February 5, 2025 by 25 Comments

If you’re like most makers, you have a few product ideas kicking about, but you may not have made it all the way to production of those things. If you’re thinking about making the leap, [Simone Giertz] recently discussed all the perils and pitfalls of the process from idea to reality.

The TLDR is that there’s a big difference between making one item and making hundreds or thousands of them, which you probably already knew, but it is nice to see what sort of issues can crop up in this seemingly simple example of the Yetch Screwdriver Ring. It turns out that the metalworking skills of tool making and jewelry making rarely overlap in the contract manufacturing world.

[Giertz] also shares some of the more mundane, yet terrifying, parts of business like finally committing to bulk orders and whether it’s wise to go with intermediaries when working with suppliers overseas. She also keys us into parts of the process where things can go wrong, like how product samples typically use a different manufacturing process than bulk for practical reasons and how you need to have very specific quality control requirements not just decide if a product is good enough based on vibes.

If you’d like some more advice on making your own products, check out [Carrie Sundra]’s Supercon talk about Manufacturing on a Shoestring Budget.

Continue reading “Making Products For Fun And (Probably No) Profit” →

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.

Continue reading “Investigating Electromagnetic Magic In Obsolete Machines” →

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 26 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.

Continue reading “Hacking The 22€ BLE SR08 Smart Ring With Built-In Display” →