Curve Tracer Design For Power Vacuum Tubes Testing

February 15, 2023 by 9 Comments

Regardless of the mythical qualities that are all too often attributed to vacuum tubes, they are still components that can be damaged and wear out over time. Much like with transistors and kin, they come with a stack of datasheets, containing various curves detailing their properties and performance. These curves will change as a part ages, and validating these curves can help with debugging a vacuum tube-based circuit. This is where one can either spend an enormous sum on a commercial curve tracer like the Tektronix 570, or build your own, as [Basin Street Design] has done.

A semi-retired electronics design engineer by trade, he has previously covered the development of the curve tracer on Instructables for the version 1 and version 1.1. What this device essentially allows you to do is sweep the connected tube through its input parameter ranges, while observing the resulting curves on an attached (external) oscilloscope. Here a storage oscilloscope (or DSO) is immensely helpful to capture the curves.

In the project pages, the in-depth theory and functioning of the circuitry is explained, along with the schematics and a number of builds. The project has been around since before the VBA tracer which we covered last year, both of which are infinitely more affordable than a genuine Tektronix 570.

Thanks to [Fernando] for the tip.

Sol-20 Integrated Computer Teardown

February 14, 2023 by 19 Comments

[Action Retro] came into an antique Sol-20 computer and argues that it was the first totally integrated computer aimed at consumers that didn’t require you to buy or build some kind of terminal. These are fairly rare, so we appreciated the peek inside that you can see in the video below.

Sure, the Sol-20 wasn’t the very first computer out there in the market. It was, however, one of the first ones that didn’t need anything more exotic than a monitor to have a functional system (and the monitor was included). There were alternatives such as a Xerox Alto or a Wang 2200, but those had price tags that didn’t land them in your home. Even Apple, which would become famous for a turnkey system, was only producing the Apple I at that time. As the video points out, it was complete as long as you could build your own power supply and knew how to interface a keyboard — keeping in mind that keyboards were all wildly different in those days.

Continue reading “Sol-20 Integrated Computer Teardown” →

Matt Venn speaking at Supercon 2022

Supercon 2022: Matt Venn’s Tiny Tapeout Brings Chip Design To The Masses

February 14, 2023 by 23 Comments

Not that long ago, rolling your own printed circuit boards was difficult, time-consuming and expensive. But thanks to an army of cheap, online manufacturing services as well as high-quality free design software, any hobbyist can now make boards to rival those made by pros. A similar shift might be underway when it comes to chip design: affordable manufacturing options and a set of free software tools are slowly bringing custom chips into the realm of hackers and hobbyists. One of those working hard to democratize chip design is Matt Venn, who’s been telling us all about his current big project, called Tiny Tapeout, in his talk at Remoticon 2022.

Matt’s quest to bring IC design to the masses started in 2020, when the first open-source compatible Process Design Kit (PDK) was released to the public. A PDK is a collection of files, normally only available under strict non-disclosure agreements, that describe all the features of a specific chip manufacturing process and enable you to make a design. With this free PDK in hand and a rag-tag collection of free software tools, Matt set out to design his first chip, a VGA clock, which he taped out (released to manufacturing) in July 2020. Continue reading “Supercon 2022: Matt Venn’s Tiny Tapeout Brings Chip Design To The Masses” →

RCA’s Clear Plastic TV Wowed Crowds In 1939

February 12, 2023 by 25 Comments

In the United States in 1939, television sets still had a long way to go before they pretty much sold themselves. Efforts to do just that are what led to RCA’s Lucite Phantom Telereceiver, which aimed to show people a new way to receive broadcast media.

Created for the 1939 World’s Fair, the TRK-12 Lucite Phantom Telereceiver introduced people to the concept of television. Production models were housed in contemporary wood cabinets, but the clear acrylic (itself also a relatively new thing) units allowed curious potential customers to gaze within, and see what was inside these devices.

One interesting feature is the vertically-mounted cathode ray tube, which reflects off a mirror in the top cover of the cabinet for viewing. This meant that much of the bulk of the TRK-12 could be vertical instead of horizontal. Important, because the TRK-12 was just over a meter tall and weighed 91 kilograms (or just over 200 lbs.)

Clearly a luxury item, the TRK-12 sold for $600 which was an eye-watering sum for the time. But it was a glimpse of the future, and as usual, the future is made available a few ticks early to those who can afford the cost.

Want to see one in person? You might be in luck, because an original resides at the MZTV Museum of Television in Toronto, Canada.

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Breadboard Macropad

February 8, 2023 by 6 Comments

For their first custom, hand-wired keyboard, [terryorchard] aka [70rch] didn’t want to mess with making a total split, and we don’t really blame them. However, as you can see, they ended up with a monoblock split, which aside from being our own personal preference, looks fantastic, and also happened to be what fit on the print bed.

What you’re looking at is a 40% remix of the Alice layout with a columnar stagger. It’s also a bit 6×3 Corne-inspired on the ergonomic front. Brain-wise, it’s got an exposed Elite Pi driving a matrix of Kailh Choc pinks and an EC11 encoder. The encoder scrolls by default, and then becomes a volume knob on the numbers and symbols layer. One super cool thing about this keyboard is the secret third layer, which is unlocked by pressing the rotary encoder. This leads to some home row mods and disables the outside columns, culminating in a test 3×5 with two layers.

Via KBD #112

Continue reading “Keebin’ With Kristina: The One With The Breadboard Macropad” →

All About USB-C: Manufacturer Sins

February 7, 2023 by 84 Comments

People experience a variety of problems with USB-C. I’ve asked people online about their negative experiences with USB-C, and got a wide variety of responses, both on Twitter and on Mastodon. In addition to that, communities like r/UsbCHardware keep a lore of things that make some people’s experience with USB-C subpar.

In engineering and hacking, there’s unspoken things we used to quietly consider as unviable. Having bidirectional power and high-speed data on a single port with thousands of peripherals, using nothing but a single data pin – if you’ve ever looked at a schematic for a proprietary docking connector attempting such a feat, you know that you’d find horrors beyond comprehension. For instance, MicroUSB’s ID pin quickly grew into a trove of incompatible resistor values for anything beyond “power or be powered”. Laptop makers had to routinely resort to resistor and one-wire schemes to make sure their chargers aren’t overloaded by a laptop assuming more juice than the charger can give, which introduced a ton of failure modes on its own.

When USB-C was being designed, the group looked through chargers, OTG adapters, display outputs, docking stations, docking stations with charging functions, and display outputs, and united them into a specification that can account for basically everything – over a single cable. What could go wrong?

Of course, device manufacturers found a number of ways to take everything that USB-C provides, and wipe the floor with it. Some of the USB-C sins are noticeable trends. Most of them, I’ve found, are manufacturers’ faults, whether by inattention or by malice; things like cable labelling are squarely in the USB-C standard domain, and there’s plenty of random wear and tear failures.

I don’t know if the USB-C standard could’ve been simpler. I can tell for sure that plenty of mistakes are due to device and cable manufacturers not paying attention. Let’s go through the notorious sins of USB-C, and see what we can learn. Continue reading “All About USB-C: Manufacturer Sins” →

Ask Hackaday: The Ten Dollar Digital Mixing Desk?

February 6, 2023 by 110 Comments

There comes a point in every engineer’s life at which they need a mixing desk, and for me that point is now. But the marketplace for a cheap small mixer just ain’t what it used to be. Where once there were bedroom musicians with a four-track cassette recorder if they were lucky, now everything’s on the computer. Lay down as many tracks as you like, edit and post-process them digitally without much need for a physical mixer, isn’t it great to be living in the future!

This means that those bedroom musicians no longer need cheap mixers, so the models I was looking for have disappeared. In their place are models aimed at podcasters and DJs. If I want a bunch of silly digital effects or a two-channel desk with a crossfader I can fill my boots, but for a conventional mixer I have to look somewhat upmarket. Around the three figure mark are several models, but I am both a cheapskate and an engineer. Surely I can come up with an alternative. Continue reading “Ask Hackaday: The Ten Dollar Digital Mixing Desk?” →