Bubble Displays Make A Neat Retro Clock

May 28, 2025 by 6 Comments

In 2025 we are spoiled for choice when it comes to displays, with affordable LCDs, OLEDs, TFTs, and e-ink panels of all sizes only a few clicks away. But in decades past, such exotica were not on the menu for casual construction. Instead there were a range of LED seven segment displays which have now largely passed out of use.

Among them were HP’s bubble displays, assemblies of miniature LEDs on a PCB, topped with plastic bubble lenses. If you had a calculator in the 1970s it probably had one, but in the present, [Joshua Coleman] has incorporated one into a pleasingly retro digital clock.

Inside the 3D printed case is an ESP32 with a pair of 74HC595 shift registers to drive the display, and an 18650 battery with all associated charging and protection circuitry. It’s a surprisingly simple circuit, and the code is provided on the page. He makes an apology to non-Americans for his use of US date formats, but we think few readers will be unable to change it to reflect the only date format which really matters.

If you find a bubble display, hang on to it. They’re certainly something we’ve seen before here a few times.

Remotely Interesting: Stream Gages

May 28, 2025 by 32 Comments

Near my childhood home was a small river. It wasn’t much more than a creek at the best of times, and in dry summers it would sometimes almost dry up completely. But snowmelt revived it each Spring, and the remains of tropical storms in late Summer and early Fall often transformed it into a raging torrent if only briefly before the flood waters receded and the river returned to its lazy ways.

Other than to those of us who used it as a playground, the river seemed of little consequence. But it did matter enough that a mile or so downstream was some sort of instrumentation, obviously meant to monitor the river. It was — and still is — visible from the road, a tall corrugated pipe standing next to the river, topped with a box bearing the logo of the US Geological Survey. On occasion, someone would visit and open the box to do mysterious things, which suggested the river was interesting beyond our fishing and adventuring needs.

Although I learned quite early that this device was a streamgage, and that it was part of a large network of monitoring instruments the USGS used to monitor the nation’s waterways, it wasn’t until quite recently — OK, this week — that I learned how streamgages work, or how extensive the network is. A lot of effort goes into installing and maintaining this far-flung network, and it’s worth looking at how these instruments work and their impact on everyday life.

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Washington Consumers Gain Right To Repair For Cellphones And More

May 28, 2025 by 30 Comments

Starting January 1st, 2026, Washington state’s new Right to Repair law will come into effect. It requires manufacturers to make tools, parts and documentation available for diagnostics and repair of ‘digital electronics’, including cellphones, computers and similar appliances. The relevant House Bill 1483 was signed into law last week after years of fighting to make it a reality.

A similar bill in Oregon faced strong resistance from companies like Apple, despite backing another Right to Repair bill in California. In the case of the Washington bill, there were positive noises from the side of Google and Microsoft, proclaiming themselves and their products to be in full compliance with such consumer laws.

Of course, the devil is always in the details, with Apple in particular being a good example how to technically comply with the letter of the law, while throwing up many (financial) roadblocks for anyone interested in obtaining said tools and components. Apple’s penchant part pairing is also a significant problem when it comes to repairing devices, even if these days it’s somewhat less annoying than it used to be — assuming you’re running iOS 18 or better.

That said, we always applaud these shifts in the right direction, where devices can actually be maintained and repaired without too much fuss, rather than e.g. cellphones being just disposable items that get tossed out after two years or less.

Thanks to [Robert Piston] for the tip.

Stamp breakout boards.

Stamp: Modular Breakout Boards For SMD Prototyping

May 28, 2025 by 36 Comments

[Kalesh Sasidharan] from Sciotronics wrote in to tell us about their project, Stamp: a modular set of template breakout boards designed to make prototyping with SMD components faster, easier, and more affordable. No breadboards, custom PCBs, or tangled jumper wires required. The project has blasted past its Kickstarter goal, and is on track to start shipping in September.

Stamp was created out of frustration with the traditional SMD prototyping workflow. Breadboards don’t support SMD parts directly, and using adapters quickly gets messy, especially when you need to iterate or modify a design. Ordering PCBs for every small revision just adds delay, and cost.

Stamp solves this by offering reusable template boards with commonly used SMD footprints. You place the main component on the front and the supporting components on the back. Many complete circuits, such as buck converters, sensor blocks, microcontrollers, and so on, can fit on a single 17.8 × 17.8 mm board.

Most Stamps feature custom castellated holes, designed for side-by-side or right-angle edge connections, enabling a modular, reconfigurable approach to circuit building. The plan is to make the designs fully open source, so that others can build or adapt them. Although many PCB manufacturers might not have the facilities to make the special castellated edges which are available on some Stamps.

Dave Jones from the EEVblog covered the Stamp on one of his recent Mailbag videos, which you can check out below. This isn’t the first time we’ve seen somebody promise to reinvent the breadboard, but we do appreciate the simplicity of this approach.

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A 100-Year-Old Electronic Musical Instrument Brought Back To Life

May 27, 2025 by 35 Comments

In the early years of electrification, when electricity was beginning to shape the modern world, this new technology was being put to use in many more places than turning motors and providing lighting. Some things we can see as obvious missteps like electrified corsets marketed as health tonics or x-ray treatments for eye strain, but others ended up being fascinating bits of technology with interesting uses, many of which have been largely forgotten since. This 100-year-old musical instrument is squarely in the latter category, and this build brings the sound of it back to life.

The instrument was called the Luminaphone and was originally built by [Harry Grindell Matthews]. Of course, this was an age before transistors and many other things we take for grated, so it has some quirks that we might not otherwise expect from a musical instrument. The device generated sound by shining a series of lights through a perforated rotating disc at a selenium cell. The selenium cell was an early photoresistor, generating current corresponding to the amount of light falling on it. A keyboard activated different lights, shining on areas of the disc with different numbers of holes, causing differing sounds to be produced by the instrument.

The recreation was built by [Nick Bild] and uses a laser diode as a stand-in for the rotating disc, but since it can be modulated in a similar way the idea is that the photodiode used as a receiver would generate a similar sound. The recreation sounds a bit like a video game from the 8-bit era, but with no recordings or original Luminaphones surviving to the present day we may never know how accurate it is. There are some other electronic instruments still around today, though, and plenty of ways of DIY-ing their sound like this project which recreates the tonewheels of the classic Hammond organ.

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The supermaterial lattice.

New Supermaterial: As Strong As Steel And As Light As Styrofoam

May 27, 2025 by 64 Comments

Today in material science news we have a report from [German Science Guy] about a new supermaterial which is as strong as steel and as light as Styrofoam!

A supermaterial is a type of material that possesses remarkable physical properties, often surpassing traditional materials in strength, conductivity, or other characteristics. Graphene, for example, is considered a supermaterial because it is extremely strong, lightweight, and has excellent electrical conductivity.

This new supermaterial is a carbon nanolattice which has been developed by researchers from Canada and South Korea, and it has remarkably high strength and remarkably low weight. Indeed this new material achieved the compressive strength of carbon steels (180-360 MPa) with the density of Styrofoam (125-215 kg m-3).

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Camera is seen on the left with an Arduino connected to the right

Look To The Sky With This Simple Plane Tracker

May 27, 2025 by 12 Comments

Do you ever get tired of stressing your neck looking for planes in the sky? Worry not! Here is a neat and cheap Arduino/Ras Pi project to keep your neck sore free! [BANK ANGLE] presents a wonderfully simple plane tracking system using an affordable camera and basic microcontrollers.

The bulk of the system relies on a cheap rotating security camera that gets dissected to reveal its internals. Here stepper control wires can be found and connected to the control boards required to allow an Arduino nano to tell the motors when and where to spin. Of course, the camera system doesn’t just look everywhere until it finds a plane, a Raspberry Pi takes in data from local ADS-B data to know where a nearby plane is.

After that, all that’s left is a nifty overlay to make the professional look. Combining all these creates a surprisingly capable system that gives information on the aircraft’s azimuth, elevation, and distance.

If you want to try your hand at making your own version of [BLANK ANGLE]’s tracker, check out his GitHub page. Of course, tracking planes gets boring after a while so why not try tracking something higher with this open-source star tracker?

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