The times they are a-changin’. It used to be that no household was complete without a drawer filled with an assortment of different sizes and types of batteries, but today more and more of our gadgets are using integrated rechargeable cells. Whether or not that’s necessarily an improvement is probably up for debate, but the fact of the matter is that some of these old batteries are becoming harder to find as time goes on.
Which is why [Stephen Arsenault] wants to preserve as many of them as possible. Not in some kind of physical battery museum (though that does sound like the sort of place we’d like to visit), but digitally in the form of 3D models and spec sheets. The idea being that if you find yourself in need of an oddball, say the PRAM battery for a Macintosh SE/30, you could devise your own stand-in with a printed shell.
The rather brilliantly named Battery Backups project currently takes the form of a Thingiverse Group, which allows other alkaline aficionados to submit their own digitized cells. The cells that [Stephen] has modeled so far include not only the STL files for 3D printing, but the CAD source files in several different flavors so you can import them into your tool of choice.
Like the efforts to digitally preserve vintage input devices, it’s not immediately clear how many others out there are willing to spend their afternoons modeling up antiquated batteries. But then again, we’ve long since learned not to underestimate the obscure interests of the hacker community.
LEDs are now a mature technology, with all manner of colors and flavors available. However, back in the 1970s, it was early days for this fledgling display tech, and things looked very different. [IMSAI Guy] happened to work at the optoelectronics division of Hewlett-Packard during their development of LED displays, and has a handful of prototypes from those heady days.
The video is a great look at not only vintage display hardware, but also rarely seen prototypes that seldom left the HP offices. Matrix, 7-segment and even 16-segment devices are all in attendance here. There’s great macro photography of the packages, including the now-forgotten bubble displays as well as hermetically sealed glass packages. The parts all have a uniquely 1970s look, drenched in gold plating and otherwise just looking very expensive.
The followup video breaks out the microscope and powers up the displays. [IMSAI Guy] shares some useful tips on how to best tinker with unknown LED parts, as well as knowledge about the chemical compounds and manufacturing processes involved in LED production. If you don’t know your III-V compounds from your II-VI compounds, prepare to learn.
It’s always interesting to take a look back, and even better to get a peek at the experiments of engineers of the past.
If you’re wondering about applications of this hardware, we’ve seen messageboards and watches before. Video after the break.
Continue reading “Let’s Look At Some Cool Old LEDs”
Over the years, computers have become faster, but at the same time, more power hungry as well. Way back around the 386 era, most PCs were using the AT standard for power supplies. Since then, the world moved on to the now ubiquitous ATX standard. Hobbyists working on older machines will typically use these readily available supplies with basic adapters to run old machines, but [Samuel] built a better one.
Most AT to ATX adapters are basic passive units, routing the various power lines where they need to go and tying the right pin high to switch the ATX supply on. However, using these with older machines can be fraught with danger. Modern supplies are designed to deliver huge currents, over 20 A in some cases, to run modern hardware. Conversely, a motherboard from the early 90s might only need 2 or 3A. In the case of a short circuit, caused by damage or a failed component, the modern supply will deliver huge current, often damaging the board, due to the overcurrent limit being set so high.
[Samuel]’s solution is to lean on modern electronics to build an ATX to AT adapter with programmable current protection. This allows the current limit to be set far lower in order to protect delicate boards. The board can be set up in both a “fast blow” and a “slow blow” mode to suit various working conditions, and [Samuel] reports that with alternative cabling, it can also be used to power up other old hardware such as Macintosh or Amiga boards. The board is even packed with extra useful features like circuitry to generate the sometimes-needed -5V rail. It’s all programmed through DIP switches and even has an OLED display for feedback.
It’s an adapter that could save some rare old hardware that’s simply irreplaceable, and for that reason alone, we think it’s a highly important build. We’ve talked about appropriate fusing and current limiting before, too – namely, with LED strips.