How Would A Field Sequential Home Computer Have Worked?

March 12, 2026 by Jenny List 13 Comments

The early history of colour TV had several false starts, of which perhaps one of the most interesting might-have-beens was the CBS field-sequential system. This was a rival to the nascent system which would become NTSC, which instead of encoding red, green, and blue all at once for each pixel, made sequential frames carry them.

The Korean war stopped colour TV development for its duration in the early 1950s, and by the end of hostilities NTSC had matured into what we know today, so field-sequential colour became a historical footnote. But what if it had survived? [Nicole Express] takes into this alternative history, with a look at how a field-sequential 8-bit home computer might have worked.

The CBS system had a much higher line frequency in order to squeeze in those extra frames without lowering the overall frame rate, so given the clock speeds of the 8-bit era it rapidly becomes obvious that a field-sequential computer would be restricted to a lower pixel resolution than its NTSC cousin. The fantasy computer discussed leans heavily on the Apple II, and we explore in depth the clock scheme of that machine.

While it would have been possible with the faster memory chips of the day to achieve a higher resolution, the conclusion is that the processor itself wasn’t up to matching the required speed. So the field-sequential computer would end up with wide pixels. After a look at a Breakout clone and how a field-sequential Atari 2600 might have worked, there’s a conclusion that field-sequential 8-bit machines would not be as practical as their NTSC cousins. From where we’re sitting we’d expect them to have used dedicated field-sequential CRT controller chips to take away some of the heartache, but such fantasy silicon really is pushing the boundaries.

Meanwhile, while field-sequential broadcast TV never made it, we do have field-sequential TV here in 2026, in the form of DLP projectors. We’ve seen their spinning filter disks in a project or two.

1950 CBS color logo: Archive.org, CC0.

A Radio Power Amplifier For Not A Lot

March 11, 2026 by Jenny List 12 Comments

When building a radio transmitter, unless it’s a very small one indeed, there’s a need for an amplifier before the antenna. This is usually referred to as the power amplifier, or PA. How big your PA is depends on your idea of power, but at the lower end of the power scale a PA can be quite modest. QRP, as lowe power radio is referred to, has a transmit power in the miliwatts or single figure watts. [Guido] is here with a QRP PA that delivers about a watt from 1 to 30 MHz, is made from readily available parts, and costs very little.

Inspired by a circuit from [Harry Lythall], the prototype is built on a piece of stripboard. It’s getting away with using those cheap transistors without heatsinking because it’s a class C design. In other words, it’s in no way linear; instead it’s efficient, but creates harmonics and can’t be used for all modes of transmission. This PA will need a low-pass filter to avoid spraying the airwaves with spurious emissions, and on the bands it’s designed for, is for CW, or Morse, only.

We like it though, as it’s proof that building radios can still be done without a large bank balance. Meanwhile if the world of QRP interests you, it’s something we have explored in the past.

A Rotary Dial The 3D Printed Way

March 11, 2026 by Jenny List 3 Comments

There’s a meme which may have a basis in truth, of a teenager left clueless when presented with a rotary telephone. The dial, in reality a mechanical pulse chain generator, was once ubiquitous enough that having one in your parts bin was anything but unusual. If you’re curious about their inner workings in 2026 though, you may be out of luck. Never fear though, because [Moeya 3D Designs] is here with a fully 3D printed version. It’s not as compact as the original, but it’s all there.

If you’re not put off by the anime-style Japanese voice over on the video below the break and you can enable subtitles for your language, you get the full explanation. There’s a ratchet and spring on the dial, which when released drives a gear train that ends in a cam that would operate a switch for the pulses. Another set of gears drives a very neatly designed centrifugal speed governor, and we see the effect immediately when it is removed. We’re not sure who will go for this project, but we surely like it.

There are two videos below the break, with the dial shown off in the first and the design process in the second. Meanwhile we’ve talked in the past about the networks behind the dials. Continue reading “A Rotary Dial The 3D Printed Way” →

Power Control For A Busy Workbench

March 10, 2026 by Jenny List 29 Comments

Who among us does not have a plethora of mains-powered devices on their workbench, and a consequent mess of power strips to run them all? [Jeroen Brinkman] made his more controllable with a multi-way switch box.

At first sight it’s a bank of toggle switches, one for each socket. But this is far more than a wiring job, because of course there are a couple of microcontrollers involved, and each of those switches ultimately controls a relay. There are also status LEDs for each socket, and a master switch to bring them all down. Arduino code is provided, so you can build one too if you want to.

We like the idea of a handy power strip controller, and especially the master switch with the inherent state memory provided by the switches. This could find a home on a Hackaday bench, and we suspect on many others too. It’s by no means the first power strip with brains we’ve seen, but most others have been aimed at the home instead.

Ask Hackaday: What Will An LLM Be Good For In The Plateau Of Productivity?

March 9, 2026 by Jenny List 70 Comments

A friend of mine has been a software developer for most of the last five decades, and has worked with everything from 1960s mainframes to the machines of today. She recently tried AI coding tools to see what all the fuss is about, as a helper to her extensive coding experience rather than as a zero-work vibe coding tool. Her reaction stuck with me; she referenced her grandfather who had been born in rural America in the closing years of the nineteenth century, and recalled him describing the first time he saw an automobile.

Après Nous, Le Krach

The Gartner hype cycle graph. Jeremykemp, CC BY-SA 3.0.

We are living amid a wave of AI slop and unreasonable hype so it’s an easy win to dunk on LLMs, but as the whole thing climbs towards the peak of inflated expectations on the Gartner hype cycle perhaps it’s time to look forward. The current AI hype is inevitably going to crash and burn, but what comes afterwards? The long tail of the plateau of productivity will contain those applications in which LLMs are a success, but what will they be? We have yet to hack together a working crystal ball, but perhaps it’s still time to gaze into the future. Continue reading “Ask Hackaday: What Will An LLM Be Good For In The Plateau Of Productivity?” →

Experiment With The Pi Camera The Modular Way

March 8, 2026 by Jenny List 6 Comments

The various Raspberry Pi camera modules have become the default digital camera hacker’s tool, and have appeared in a huge number of designs over the past decade. They’re versatile and affordable, and while the software can sometimes be a little slow, they’re also of decent enough quality for the investment. Making a Pi camera can be annoying though, because different screens, lenses, and modules have their own mounting requirements. [Jacob David C Cunningham] has a solution here, with a modular Raspberry Pi camera, as an experimentation platform for different screens and lenses.

It takes the form of a central unit that holds the Pi and its support components, and front and rear modules for the screens or displays. Examples are given using the HQ and non-HQ modules, as well as with round or rectangular displays.

When designing a camera for 3D printing it’s a very difficult task, to replicate or exceed the industrial design of commercial cameras. Few succeed, and we’d include ourselves among that number. But this one comes close; it looks like a camera we’d like to use. We like it.

Instant Photography For The Maker

March 7, 2026 by Jenny List No comments

Instant photography is a miracle of the analog age, chemical photographs that develop in your hands moments after the shutter has been pressed. You can buy instant cameras and film from Fuji and the successor company to Polaroid, the originator of the technology, but they’re expensive. Fortunately [BoxArt] is here for those seeking a cheaper alternative, with an instant camera featuring a Raspberry Pi and a printer (Lithuanian language, Google Translate link).

It’s a fairly straightforward arrangement, with the Pi Zero and camera driving a receipt printer. There’s a nicely engineered 3D printed case, and the guts of a power bank to provide the volts for the thing. There are a set of status lights on top, and that’s it. Press the button, get a not-very-good grayscale image on curly paper.

You can of course buy off-the-shelf grayscale printing cameras from your favorite import site for much less than the cost of this camera, but we think this would probably take better pictures. Meanwhile if the original instant photography interests you, we’ve got you covered.