Retrotechtacular: Remembering Radio Shack P-Box Kits

December 14, 2018 by 86 Comments

If you are under a certain age, you probably associate Radio Shack with cellphones. While Radio Shack never gave us access to the variety and economy of parts we have today, they did have one thing that I wish we could get again: P-Box kits. The obvious questions are: What’s a P-Box and why do I want one? But the kit wasn’t to make a P-Box. P-Box was the kind of box the kit came in. It was like a piece of perfboard, but made of plastic, built into a plastic box. So you bought the kit — which might be a radio or a metal detector — opened the box and then built the kit using the box as the chassis.

The perfboard was pretty coarse, too, because the components were all big discrete components. There was at least one that had an IC, but that came premounted on a PC board that you treated like a big component. One of my favorites was a three-transistor regenerative shortwave receiver. In those days, you could pick up a lot of stations on shortwave and it was one of the best ways at the time to learn more about the world.

On the left, you can see a picture of the radio from the 1975 catalog. You might think $7.95 is crazy cheap, but that was at least a tank full of gas or four movie tickets in those days, and most of us didn’t have a lot of money as kids, so you probably saved your allowance for a few weeks, did chores, or delivered papers to make $8.

Continue reading “Retrotechtacular: Remembering Radio Shack P-Box Kits” →

Let’s Look At Some Cool Old LEDs

December 14, 2018 by 17 Comments

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” →

Charge Your EV The Portable Way

December 14, 2018 by 37 Comments

[Andrew Rossignol] has a slightly unusual plug-in hybrid vehicle, a Cadillac ELR, and his latest project for the car sees him building a battery-powered portable mains charging pack for it in an attempt to increase its range. If this seems to be a rather cumbersome exercise, his write-up details the work he put in trying to hook up directly to the car’s internal battery, and how a 4 kW mains inverter and an off-the-shelf mains charging station were the most practical alternative.

His first impulse was to hook a second supply to the car’s high voltage bus from a supplementary battery pack and inverter, but in this aim he was thwarted by a protection diode and his not wanting to modify the car to bypass it. So the unlikely solution was to take his battery pack from a second-hand Toyota Prius upgrade kit and build it into a frame along with the inverter and charger. The result is something akin to a portable generator without the small gasoline engine, and while it is hardly the most efficient way to transfer energy from a wall socket into a car it does offer the ELR a significant range upgrade.

The cost involved has probably kept away many readers who would like to hack their hybrid cars, so we’ve seen surprisingly few. This home made Geo Metro supplements its forklift motor with a small gasoline generator. Meanwhile [Andrew] is no stranger to these pages, among the several times his work has appeared here are his rundown on OBD sniffing the ELR, and from a while back, displaying graphics on an oscilloscope including a Wrencher.

Turn Old Pinball Parts Into A Unique Digital Clock

December 13, 2018 by 25 Comments

It’s getting ever harder to build a truly unique digital clock. From electronic displays to the flip-dots and flip-cards, everything seems to have been done to death. But this pinball scoring reel clock manages to keep the unique clock ball in play, as it were.

It’s not entirely clear whom to credit with this build, but the article was written by [Lucky]. Nor do they mention which pinball machine gave up its electromechanical scoring display for the build. Our guess would be a machine from the ’60s, before the era of score inflation that required more than the four digits used. And indeed, the driver for the display is designed so that a scoring unit from any pinball machine from the electromechanical era can be used. An ESP8266 keeps the time with the help of an RTC and drives the coils of the scoring unit through a bunch of MOSFETs. The video below shows that it wouldn’t make a great clock for the nightstand; thankfully, it has a user-configured quiet time to limit the not inconsiderable noise to waking hours. It also flashes the date every half hour, rings solenoid operated chimes, and as a bonus, it can be used to keep score in a pinball game built right into the software.

We like the idea of honoring the old pinball machines with clock builds like this. We’ve seen a word clock built from the back-glass of an old machine, and one that uses a four-player back to display the date and alarm time too.

Continue reading “Turn Old Pinball Parts Into A Unique Digital Clock” →

A Cheat Sheet For Publishing Python Packages

December 13, 2018 by 5 Comments

[Brendan Herger] was warned that the process of publishing a Python package would be challenging. He relishes a challenge, however, and so he went at it with gusto. The exhausting process led him to share a cheat sheet for publishing Python packages with the goal of making the next time smoother, while also letting other people benefit from his experience and get a running start.

[Brendan] describes publishing a Python package as “tying together many different solutions with brittle interchanges.” His cheat sheet takes the form of an ordered workflow for getting everything in place, with some important decisions and suggestions about things like formatting and continuous integration (CI) made up-front.

The guide is brief, but [Brendan] has made errors and hit dead ends in the hopes that others won’t have to. The whole thing came about from his work in deep learning, and his desire to create a package that allows rapid building and iterating on deep learning models.

Deep learning is a type of machine learning that involves finding representations in large amounts of data. [Brendan] used it in a project to automatically decide whether a Reddit post contains Star Wars plot spoilers, and we recently saw it featured in a method of capturing video footage only if a hummingbird is present.

How To Make A Pilotron, The Forgotten Tube

December 13, 2018 by 21 Comments

The vacuum tube is largely ignored in modern electronic design, save for a few audio applications such as guitar and headphone amps. The transistor is smaller, cheaper, and inordinately easier to manufacture. By comparison, showing us just how much goes into the manufacture of a tube, [glasslinger] decided to make a wire-element pilotron – from scratch!

To say this is an involved build is an understatement. Simply creating the glass tube itself takes significant time and skill. [glasslinger] shows off the skills of a master, however – steadily working through the initial construction, before showing off advanced techniques necessary to seal in electrodes, produce the delicate wire grid, and finally pull vacuum and seal the tube completely.

The project video is an hour long, and no detail is skipped. From 2% thoriated tungsten wire to annealing torches and grades of glass, it’s all there. It’s enough that an amateur could reproduce the results, given enough attempts and a complete shop of glassworking equipment.

The pilotron may be a forgotten design, but in 2018 it once again gets its day in the sun. Overall, it’s a testament to [glasslinger]’s skill and ability to be able to produce such a device that not only looks the part, but is fully functional on an electronic level, as well.

There’s a few people out there still building valves the old fashioned way, and we’d love to see more – tip ’em if you got ’em. Video after the break.

[Thanks to Morris for the tip!]

Continue reading “How To Make A Pilotron, The Forgotten Tube” →

Every Computer Deserves A Rotary Encoder

December 13, 2018 by 26 Comments

In the era of touch screens and capacitive buttons, we’d be lying if we said we didn’t have the occasional pang of nostalgia for the good old days when interfacing with devices had a bit more heft to it. The physical clunk and snap of switches never seems to get old, and while you can always pick up a mechanical keyboard for your computer if you want to hear that beautiful staccato sound while firing off your angry Tweets, there’s a definite dearth of mechanical interface devices otherwise.

[Jeremy Cook] decided to take matters into his own hands (literally and figuratively) by designing his own multipurpose USB rotary input device. It’s not a replacement for the mouse or keyboard, but a third pillar of the desktop which offers a unique way of controlling software. It’s naturally suited to controlling things like volume or any other variable which would benefit from some fine tuning, but as demonstrated in the video after the break even has some gaming applications. No doubt the good readers of Hackaday could think of even more potential applications for a gadget like this.

The device is built around the diminutive Arduino-compatible PICO board by MellBell, which features a ATmega32u4 and native USB. This allowed him to very rapidly spin up a USB Human Interface Device (HID) with minimal headaches, all he had to do was hang his buttons and rotary encoder on the PICO’s digital pins. To that end, he [Jeremy] used the fantastic I2C rotary encoder designed by [fattore.saimon], which readers may remember as a finalist in the Open Hardware Design Challenge phase of the 2018 Hackaday Prize. He also added a NeoPixel ring around the encoder to use for some visual feedback and because, well, it just looks cool.

Since all of the core components are digital, there’s not a whole lot required in the way of wiring or passive components. This let [Jeremy] put the whole thing together on a piece of perfboard, freeing him up to spend time designing the 3D printed enclosure complete with translucent lid so he can see the NeoPixel blinkenlights. He got the tolerances tight enough that the whole device can be neatly press-fit together, and even thought to add holes in the bottom of the case so he could push the perfboard back out if he needed to down the line.

[Jeremy] spends a good chunk of the video going over the software setup and development of the firmware, and details some of the nuances he had to wrap his head around when working with the I2C encoder. He also explains the math involved in getting his encoder to emulate a mouse cursor moving in a circle, which he thinks could be useful when emulating games that originally used an encoder such as Tempest or Pong.

We’ve seen similar USB “knobs” in the past for controlling volume, but the additional inputs that [Jeremy] built into his version definitely makes it a bit more practical. Of course we’re suckers for interesting USB input devices to begin with.

Continue reading “Every Computer Deserves A Rotary Encoder” →