Ancient Cable Modem Reveals Its RF Secrets

April 22, 2024 by 27 Comments

Most reverse engineering projects we see around here have some sort of practical endpoint in mind. Usually, but not always. Reverse-engineering a 40-year-old cable modem probably serves no practical end, except for the simple pleasure of understanding how 1980s tech worked.

You’ll be forgiven if the NABU Network, the source of the modem [Jared Boone] tears into, sounds unfamiliar; it only existed from 1982 to 1985 and primarily operated in Ottawa, Canada. It’s pretty interesting though, especially the Z80-based computer that was part of the package. The modem itself is a boxy affair bearing all the hallmarks of 1980s tech. [Jared]’s inspection revealed a power supply with a big transformer, a main logic board, and a mysterious shielded section with all the RF circuits, which is the focus of the video below.

Using a signal generator, a spectrum analyzer, and an oscilloscope, not to mention the PCB silkscreen and component markings, [Jared] built a block diagram of the circuit and determined the important frequencies for things like the local oscillator. He worked through the RF section, discovering what each compartment does, with the most interesting one probably being the quadrature demodulator. But things took a decidedly digital twist in the last compartment, where the modulated RF is turned into digital data with a couple of 7400-series chips, some comparators, and a crystal oscillator.

This tour of 80s tech and the methods [Jared] used to figure out what’s going on in this box were pretty impressive. There’s more to come on this project, including recreating the original signal with SDRs. In the mean time, if this put you in the mood for other videotext systems of the 80s, you might enjoy this Minitel terminal teardown.

Continue reading “Ancient Cable Modem Reveals Its RF Secrets” →

AI + LEGO = A Brickton Of Ideas

April 22, 2024 by 38 Comments

What if there was some magic device that could somehow scan all your LEGO and tell you what you can make with it? It’s a childhood dream come true, right? Well, that device is in your pocket. Just dump out your LEGO stash on the carpet, spread it out so there’s only one layer, scan it with your phone, and after a short wait, you get a list of all the the fun things you can make. With building instructions. And oh yeah, it shows you where each brick is in the pile.

We are talking about the BrickIt app, which is available for Android and Apple. Check it out in the short demo after the break. Having personally tried the app, we can say it does what it says it does and is in fact quite cool.

As much as it may pain you to have to pick up all those bricks when you’re finished, it really does work better against a neutral background like light-colored carpet. In an attempt to keep the bricks corralled, we tried a wooden tray, and it didn’t seem to be working as well as it probably could have — it didn’t hold that many bricks, and they couldn’t be spread out that far.

And the only real downside is that results are limited because there’s a paid version. And the app is kind of constantly reminding you of what you’re missing out on. But it’s still really, really cool, so check it out.

We don’t have to tell you how versatile LEGO is. But have you seen this keyboard stand, or this PCB vise?

Continue reading “AI + LEGO = A Brickton Of Ideas” →

Slicing And Dicing The Bits: CPU Design The Old Fashioned Way

April 22, 2024 by 8 Comments

Writing for Hackaday can be somewhat hazardous. Sure, we don’t often have to hide from angry spies or corporate thugs. But we do often write about something and then want to buy it. Expensive? Hard to find? Not needed? Doesn’t really matter. My latest experience with this effect was due to a recent article I wrote about the AM2900 bitslice family of chips. Many vintage computers and video games have them inside, and, as I explained before, they are like a building block you use to build a CPU with the capabilities you need. I had read about these back in the 1970s but never had a chance to work with them.

As I was writing, I wondered if there was anything left for sale with these chips. Turns out you can still get the chips — most of them — pretty readily. But I also found an eBay listing for an AM2900 “learning and evaluation kit.” How many people would want such a thing? Apparently enough that I had to bid a fair bit of coin to take possession of it, but I did. The board looked like it was probably never used. It had the warranty card and all the paperwork. It looked in pristine condition. Powering it up, it seemed to work well.

What Is It?

The board hardly looks at least 40  years old.

The board is a bit larger than a letter-sized sheet of paper. Along the top, there are three banks of four LEDs. The bottom edge has three banks of switches. One bank has three switches, and the other two each have four switches. Two more switches control the board’s operation, and two momentary pushbutton switches.

The heart of the device, though, is the AM2901, a 4-bit “slice.” It isn’t quite a CPU but more just the ALU for a CPU. There’s also an AM2909, which controls the microcode memory. In addition, there’s a small amount of memory spread out over several chips.

A real computer would probably have many slices that work together. It would also have a lot more microprogram memory and then more memory to store the actual program. Microcode is a very simple program that knows how to execute instructions for the CPU. Continue reading “Slicing And Dicing The Bits: CPU Design The Old Fashioned Way” →

How Wireless Charging Works And Why It’s Terrible

April 22, 2024 by 75 Comments

Wireless charging is pretty convenient, as long as the transmitter and receiver speak the same protocol. Just put the device you want to charge on the wireless charger without worrying about plugging in a cable. Yet as it turns out, the disadvantages of wireless charging may be more severe than you think, at least according to tests by iFixIt’s [Shahram Mokhtari] and colleagues. In the article the basics of wireless charging are covered, as well as why wireless charging wastes a lot more power even when not charging, and why it may damage your device’s battery faster than wired charging.

The inefficiency comes mostly from the extra steps needed to create the alternating current (AC) with wireless coupling between the coils, and the conversion back to DC. Yet it is compounded by the issue of misaligned coils, which further introduce inefficiencies. Though various protocols seek to fix this (Qi2 and Apple’s MagSafe) using alignment magnets, these manage to lose 59% of the power drawn from the mains due to these inefficiencies. Wireless chargers also are forced to stay active, polling for a new device to charge, which keeps a MagSafe charger sucking up 0.2 W in standby.

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The Hunt For MH370 Goes On With Barnacles As A Lead

April 22, 2024 by 39 Comments

On March 8, 2014, Malaysia Airlines Flight 370 vanished. The crash site was never found, nor was the plane. It remains one of the most perplexing aviation mysteries in history. In the years since the crash, investigators have looked into everything from ocean currents to obscure radio phenomena to try and locate the plane. All have thus far failed to find the wreckage.

It was on July 2015 when a flaperon from the aircraft washed up on Réunion Island. It was the first piece of wreckage found, and it was hoped it could provide clues to the airliner’s final resting place. While it’s yet to reveal a final answer as to the aircraft’s fate, some of the ocean life living on it could help investigators need to find the plane. The picture is murky right now, but in an investigation where details are scarce, every little clue helps.

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Going Canadian: The Rise And Fall Of Novell

April 22, 2024 by 47 Comments

During the 1980s and 1990s Novell was one of those names that you could not avoid if you came even somewhat close to computers. Starting with selling computers and printers, they’d switch to producing networking hardware like the famous NE2000 and the inevitability that was Novell Netware software, which would cement its fortunes. It wasn’t until the 1990s that Novell began to face headwinds from a new giant: Microsoft, which along with the rest of the history of Novell is the topic of a recent article by [Bradford Morgan White], covering this rise, the competition from Microsoft’s Windows NT and its ultimate demise as it found itself unable to compete in the rapidly changing market around 2000, despite flirting with Linux.

Novell was founded by two experienced executives in 1980, with the name being reportedly the misspelled French word for ‘new’ (nouveau or nouvelle). With NetWare having cornered the networking market, there was still a dearth of networking equipment like Ethernet expansion cards. This led Novell to introduce the 8-bit ISA card NE1000 in 1987, later followed by the 16-bit NE2000. Lower priced than competing products, they became a market favorite. Then Windows NT rolled in during the 1990s and began to destroy NetWare’s marketshare, leaving Novell to flounder until it was snapped up by Attachmate in 2011, which was snapped up by Micro Focus International 2014, which got gobbled up by Canada-based OpenText in 2023. Here Novell’s technologies got distributed across its divisions, finally ending Novell’s story.

A pair of hands holds a digital camera. "NUCA" is written in the hood above the lens and a black grip is on the right hand side of the device (left side of image). The camera body is off-white 3D printed plastic. The background is a pastel yellow.

AI Camera Only Takes Nudes

April 22, 2024 by 52 Comments

One of the cringier aspects of AI as we know it today has been the proliferation of deepfake technology to make nude photos of anyone you want. What if you took away the abstraction and put the faker and subject in the same space? That’s the question the NUCA camera was designed to explore. [via 404 Media]

[Mathias Vef] and [Benedikt Groß] designed the NUCA camera “with the intention of critiquing the current trajectory of AI image generation.” The camera itself is a fairly unassuming device, a 3D-printed digital camera (19.5 × 6 × 1.5 cm) with a 37 mm lens. When the camera shutter button is pressed, a nude image is generated of the subject.

The final image is generated using a mixture of the picture taken of the subject, pose data, and facial landmarks. The photo is run through a classifier which identifies features such as age, gender, body type, etc. and then uses those to generate a text prompt for Stable Diffusion. The original face of the subject is then stitched onto the nude image and aligned with the estimated pose. Many of the sample images on the project’s website show the bias toward certain beauty ideals from AI datasets.

Looking for more ways to use AI with cameras? How about this one that uses GPS to imagine a scene instead. Prefer to keep AI out of your endeavors to invade personal space? How about building your own TSA body scanner?