A Faulty Keyboard From A Single LED

July 5, 2023 by Jenny List 19 Comments

When the chance arrived to buy a mechanical keyboard for not a lot, naturally, [Hales] jumped at it. Then it started having odd intermittent problems with some keys appearing stuck, which led to a teardown and some fault finding. The culprit was a white LED — but why this was the case is a fascinating story.

Stripping it down there didn’t seem to be an obvious culprit, but eventually, the trail led to a lack of diodes in the matrix. This keyboard had an extremely clever yet rather cursed design in which it used LEDs as both illumination and as a diode in the keyboard matrix circuit, and the faulty LED had a reverse breakdown condition that could be triggered under certain operational conditions.

More unexpectedly, it would sometimes hold on to its reverse breakdown state even after power off. Just when you think you understand a component’s properties, there’s always room for surprise. And we can safely say we’ve learned something about the design of cheaper keyboards in reading the account. It’s clear that when it comes to ‘boards, it’s best to take no chances.

Cheap Ham Radio Improves The Low End UI If Not The RF

July 5, 2023 by Al Williams 17 Comments

There was a time when buying a new radio was something many hams could never afford to do. Then came the super cheap — and super controversial — VHF and UHF radios from China. But as they say, you get what you pay for. The often oddly named handhelds like Baofeng and Wouxun are sometimes odd to work with and may have questionable RF outputs. A new radio has a less tongue-twisting English name and many improved features for about $50 — the Talkpod A36Plus and [Josh] shows us how they work in a video that you can see below.

The new features are generally good. For example, the radio can pick up AM in the aircraft band, something most of these cheap radios won’t do. It works on VHF and UHF bands but also picks up FM broadcasts. The USB-C connector is welcome, and the screen is large and colorful. It has 500 channels and IP5 water resistance.

There were a few issues, though. If you want to use it as a scanner, it’s not very fast. The radio comes with a programming cable, but apparently, it uses an odd USB chipset that may give you some driver issues. The biggest problem, though, is that it has, according to the video, excessive spurious emissions. The power isn’t that high, and the antenna probably filters off some of it, too. But creating interference across the band isn’t very polite.

How bad are the harmonics? Well, [Josh] hooks up a spectrum analyzer and also shows how a radio tuned to the second harmonic easily picks up the transmission. Of course, no radio is perfect, but it seems like it does have very strong harmonic emissions. Of course, it may or may not be any worse than similar cheap radios. They are probably all above the legal limits, and it is just a matter of degrees.

These little radios won’t directly work the world — you need an HF radio for that, generally. They will let you connect to local repeaters, though. Some of those cheap radios can lead to interesting projects, too.

Continue reading “Cheap Ham Radio Improves The Low End UI If Not The RF” →

A Dusty Boat Anchor Back From The Brink

July 4, 2023 by Jenny List 16 Comments

Many of us will have found dusty forgotten pieces of electronics and nursed them back to health, but we were captivated by [Don]’s tale of electronic revival. Instead of perhaps a forgotten computer or television, his barn find was a Heathkit linear amplifier for radio amateurs. In that huge box underneath an impressive layer of grime were a pair of huge tubes, along with all the power supply components to give them the 2 kV they need. It should have been good for a kilowatt when new, can it be made to go on air again?

Perhaps understandably with such an old device, after cleaning away the dust of ages he replaced the power supply circuitry with new parts and PCBs. A linear amplifier is surprisingly simple, but because of the voltages and power concerned there’s a need to treat its power circuits with respect. On first power-up the filaments work and the rails come up, so when given some RF drive it comes alive. Coupled with a case restoration you’d never know how dreadful a state it had been in.

We like to see classic Heathkit devices here at Hackaday, though we’ve followed their more recent reappearance too.

The I960: When Intel Almost Went RISC

July 4, 2023 by Maya Posch 27 Comments

The i960 KA/KB/MC/XA with the main functional blocks labeled. Click this image (or any other) for a larger version. Die image courtesy of Antoine Bercovici. Floorplan from The 80960 microprocessor architecture.

From the consumer space it often would appear as if Intel’s CPU making history is pretty much a straight line from the 4004 to the 8080, 8088 and straight into the era of Pentiums and Cores. Yet this could not be further from the truth, with Intel having churned through many alternate architectures. One of the more successful of these was the Intel i960, which is also the topic of a recent article by [Ken Shirriff].

Remarkably, the i960 as a solid RISC (Reduced Instruction Set Computer) architecture has its roots in Intel’s ill-fated extreme CISC architecture, the iAPX 432. As [Ken] describes in his comparison between the i960 and 432, both architectures are remarkably similar in terms of their instruction set, essentially taking what it could from the 432 project and putting it into a RISC-y shape. This meant that although the i960 could be mistaken as yet another RISC CPU, as was common in the 1980s, but integrated higher-level features as well, such as additional memory protection and inter-process communication. Continue reading “The I960: When Intel Almost Went RISC” →

Quantum Computing On A Commodore 64 In 200 Lines Of BASIC

July 4, 2023 by Maya Posch 17 Comments

The term ‘quantum computer’ gets usually tossed around in the context of hyper-advanced, state-of-the-art computing devices. But much as how a 19th century mechanical computer, a discrete computer created from individual transistors, and a human being are all computers, the important quantifier is how fast and accurate the system is at the task. This is demonstrated succinctly by [Davide ‘dakk’ Gessa] with 200 lines of BASIC code on a Commodore 64 (GitHub), implementing a range of quantum gates.

Much like a transistor in classical computing, the qubit forms the core of quantum computing, and we have known for a long time that a qubit can be simulated, even on something as mundane as an 8-bit MPU. Ergo [Davide]’s simulations of various quantum gates on a C64, ranging from Pauli-X, Pauli-Y, Pauli-Z, Hadamard, CNOT and SWAP, all using a two-qubit system running on a system that first saw the light of day in the early 1980s.

Naturally, the practical use of simulating a two-qubit system on a general-purpose MPU running at a blistering ~1 MHz is quite limited, but as a teaching tool it’s incredibly accessible and a fun way to introduce people to the world of quantum computing.

3D Audio Imaging With A Phased Array Microphone

July 4, 2023 by Jonathan Bennett 28 Comments

Remember the scene from Blade Runner, where Deckard puts a photograph into a Photo Inspector? The virtual camera can pan and move around the captured scene, pulling out impossible details. It seems that [Ben Wang] discovered how to make that particular trick a reality, but with audio instead of video. The secret sauce isn’t a sophisticated microphone, but a whole bunch of really simple ones. In this case, it’s 192 of them, arranged on long PCBs working as the spokes of a wall-art wheel. Quite the conversation piece.

Continue reading “3D Audio Imaging With A Phased Array Microphone” →

2023 Cyberdeck Challenge: Reviving The First Notebook Computer

July 4, 2023 by Jenny List 7 Comments

At first sight upon seeing [Don]’s HX2023 cyberdeck project one might be sad at the destruction of a retrocomputer, but in fact its classic Epson shell comes from a pile of spare parts left after restoring many other of the classic HX20 notebook computers to working order. The result stays true to the original but gives us so much more in the shape of a Raspberry Pi, and it’s worth cracking it open to see what components make this happen.

The first impression from the pictures is how tidy it all is, with the various USB-based boards contained on a large piece of perfboard spanning the whole case. As well as a USB hub and UPS board there’s an M.2 SSD interface and an audio board, and a DSI color TFT screen neatly fitted in place of the original monochrome item. Finally, there’s an Adafruit keyboard matrix interface board, allowing the use of the Epson’s original keys.

We like this conversion, because it manages to preserve a lot of what the original Epson had that made it great. We’re reminded of a cyberdeck inspired by the other great 8-bit notebook, the TRS-80 model 100.