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

Keebin’ With Kristina: The One With The Circuit Sculpture Keyboard

January 7, 2025 by 2 Comments

The left half of GEMK-47, a mechanical keyboard with a round screen.
Image by [New-Concentrate6308] via reddit
Don’t worry, [New-Concentrate6308] is working on the GitHub for this final build of 2024, dubbed the GEMK_47. That stands for Grid Ergo Magnetic Keyboard, but I swear there are 48 keys.

What we’ve got here is a split ergo with an ortholinear layout. There’s a round screen and encoder on the left side, and a 35 mm trackpad on the right. There’s also space for some other round thing on this side, should you want another rotary encoder or whatever fits in place of the spacer.

Internally, there’s a Waveshare RP2040 Tiny and a mixture of Gateron Oil Kings and Gateron Yellow V3 switches. That lovely case is printed in silk silver PLA, but [New-Concentrate6308] wants to try metal-filled PLA for the next version. Although the original idea was to go wireless, ZMK didn’t play nicely with that round display, which of course is non-negotiable.

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One To Watch For In 2025: Tanmatsu

January 7, 2025 by 20 Comments

If you’ve used the Espressif series of processors, perhaps you’ll have heard of their upcoming ESP32-P4. This is an application processor, with dual RISC-V cores at 400 MHz, and save for a lack of an MMU, a spec sheet much closer to the kind of silicon you’d find in single board computers with pretensions towards being a mini-PC.

It was announced a year ago and there have been limited numbers of pre-release versions of the chip available to developers, but thus far there have been very few boards featuring it. We’re excited then to note that a P4-based board we’ve been watching for a while is finally breaking cover, and what’s more, you can now pre-order one.

The Tanmatsu (Japanese for “Terminal”) is an all-in-one palmtop computer for hackers, with a QWERTY keyboard and an 800×480 DSI display. It’s designed with plenty of expansion in mind, and it’s got space on board for a LoRa radio. The reason we’re interested is that it comes from some of our friends in the world of event badges, so we’ve seen and handled real working prototypes, and we know that its makers come from a team with a proven record in manufacture and delivery of working hardware. The prototype we saw had hardware that was very close to the final version, and an operating system and software that was still under development but on track for the April release of the device. It will be fully open-source in both hardware and software.

We liked what we saw and have pre-ordered one ourselves, so we’ll be sure to bring you a closer look when it arrives.

Logging Baby’s Day In Linux

January 7, 2025 by 39 Comments

There’s plenty of surprises to be had when you become a parent, and one of the first is that it’s suddenly your job to record  the frequency of your infant’s various bodily functions in exacting detail. How many times did the little tyke eat, how long did they sleep, and perhaps most critically, how many times did they poop. The pediatrician will expect you to know these things, so you better start keeping notes.

Or, if you’re [Triceratops Labs], you build a physical button panel that will keep tabs on the info for you. At the press of each button, a log entry is made on the connected Raspberry Pi Zero W, which eventually makes its way to a web interface that you can view to see all of Junior’s statistics.

In terms of hardware, this one is quite simple — it’s really just an array of arcade-style push buttons wired directly into the Pi’s GPIO header. Where it shines is in the software. This project could have been just a Python script and a text file, but instead it uses a MariaDB database on the back-end, with Apache and PHP serving up the web page, and a custom Systemd service to tie it all together. In other words, it’s what happens when you let a Linux admin play with a soldering iron.

It probably won’t come as much surprise to find that hackers often come up with elaborate monitoring systems for their newborn children, after all, it’s a great excuse for a new project. This machine learning crib camera comes to mind.

Thirty Years Later, The Windows 3.1 Video Driver You Needed

January 6, 2025 by 52 Comments

Over the course of the 1990s we saw huge developments in the world of PC graphics cards, going from little more than the original IBM VGA standard through super VGA and then so-called “Windows accelerator” cards which brought the kind of hardware acceleration the console and 16 bit home computer users had been used to for a while. At the end of the decade we had the first generation of 3D accelerator chipsets which are ancestors of today’s GPUs.

It was a great time to be a hardware enthusiast, but as anyone who was around at the time will tell you, the software for the drivers hadn’t caught up. Particularly for Windows 3.1 it could be something of a lottery, so [PluMGMK]’s modern generic SVGA driver could have been extremely useful had it appeared at the time.

As many of you will be aware, there is a set of VESA standardized BIOS extensions for video modes. There were generic VESA drivers back in the day, but they would only provide a disappointing selection of options for what the cards could do even then. The new driver provides support for all the available modes supported by a card, at all color depths. Windows 3.1 in true-color full HD? No problem!

It’s unexpected to see Program Manager and a selection of windows spread across so much real-estate, almost reminiscent of the uncluttered desktops from early ’90s workstations if you disregard the bright colors. We can’t help noticing it wins in one way over even the latest version of MacOS at these resolutions though, as anyone who has ever used a 4K screen on a Mac and found the menus remain miles away up in the top corner will tell you. Meanwhile if you’ve not had your fill of 16-bit Windows, how about sticking it in a ThinkPad BIOS?

Rethinking Your Jellybean Op Amps

January 6, 2025 by 44 Comments

Are your jellybeans getting stale? [lcamtuf] thinks so, and his guide to choosing op-amps makes a good case for rethinking what parts you should keep in stock.

For readers of a certain vintage, the term “operational amplifier” is almost synonymous with the LM741 or LM324, and with good reason. This is despite the limitations these chips have, including the need for bipolar power supplies at relatively high voltages and the need to limit the input voltage range lest clipping and distortion occur. These chips have appeared in countless designs over the nearly 60 years that they’ve been available, and the Internet is littered with examples of circuits using them.

For [lcamtuf], the abundance of designs for these dated chips is exactly the problem, as it leads to a “copy-paste” design culture despite the far more capable and modern op-amps that are readily available. His list of preferred jellybeans includes the OPA2323, favored thanks to its lower single-supply voltage range, rail-to-rail input and output, and decent output current. The article also discussed the pros and cons of FET input, frequency response and slew rate, and the relative unimportance of internal noise, pointing out that most modern op-amps will probably be the least thermally noisy part in your circuit.

None of this is to take away from how important the 741 and other early op-amps were, of course. They are venerable chips that still have their place, and we expect they’ll be showing up in designs for many decades to come. This is just food for thought, and [lcamtuf] makes a good case for rethinking your analog designs while cluing us in on what really matters when choosing an op-amp.

Is A Cheap Frequency Standard Worth It?

January 6, 2025 by 26 Comments

In the quest for an accurate frequency standard there are many options depending on your budget, but one of the most affordable is an oven controlled crystal oscillator (OCXO). [RF Burns] has a video looking at one of the cheapest of these, a sub ten dollar AliExpress module.

A crystal oven is a simple enough device — essentially just a small box containing a crystal oscillator and a thermostatic heater. By keeping the crystal at a constant temperature it has the aim of removing thermal drift from its output frequency, meaning that once it is calibrated it can be used as a reasonably good frequency standard. The one in question is a 10 MHz part on a small PCB with power supply regulator and frequency trimming voltage potentiometer, and aside from seeing it mounted in an old PSU case we also are treated to an evaluation of its adjustment and calibration.

Back in the day such an oscillator would have been calibrated by generating an audible beat with a broadcast standard such as WWV, but in 2024 he uses an off-air GPS standard to calibrate a counter before measuring the oven crystal. It’s pretty good out of the box, but still a fraction of a Hertz off, thus requiring a small modification to the trimmer circuit. We’d be happy with that.

For the price, we can see that one of these makes sense as a bench standard, and we say this from the standpoint of a recovering frequency standard nut.

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No Frills PCB Brings USB-C Power To The Breadboard

January 6, 2025 by 30 Comments

At this point, many of us have gone all-in on USB-C. It’s gotten to the point that when you occasionally run across a gadget that doesn’t support being powered USB-C, the whole experience seems somewhat ridiculous. If 90% of your devices using the same power supply, that last 10% starts feeling very antiquated.

So why should your breadboard be any different? [Axiometa] has recently unveiled a simple PCB that will plug into a standard solderless breadboard to provide 3.3 and 5 VDC when connected to a USB-C power supply. The device is going to start a crowdfunding campaign soon if you want to buy a completed one — but with the design files and Bill of Materials already up on GitHub, nothing stops you from spinning up your own version today.

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