Engineering

597 Articles

PCIe For Hackers: The Diffpair Prelude

March 14, 2023 by 35 Comments

PCIe, also known as PCI-Express, is a highly powerful interface. So let’s see what it takes to hack on something that powerful. PCIe is be a bit intimidating at first, however it is reasonably simple to start building PCIe stuff, and the interface is quite resilient for hobbyist-level technology. There will come a time when we want to use a PCIe chip in our designs, or perhaps, make use of the PCIe connection available on a certain Compute Module, and it’s good to make sure that we’re ready for that.

PCIe is everywhere now. Every modern computer has a bunch of PCIe devices performing crucial functions, and even iPhones use PCIe internally to connect the CPU with the flash and WiFi chips. You can get all kinds of PCIe devices: Ethernet controllers, high-throughput WiFi cards, graphics, and all the cheap NVMe drives that gladly provide you with heaps of storage when connected over PCIe. If you’re hacking on a laptop or a single-board computer and you’d like to add a PCIe device, you can get some PCIe from one of the PCIe-carrying sockets, or just tap into an existing PCIe link if there’s no socket to connect to. It’s been two decades since we’ve started getting PCIe devices – now, PCIe is on its 5.0 revision, and it’s clear that it’s here to stay.

Continue reading “PCIe For Hackers: The Diffpair Prelude” →

A Hacker’s Introduction To DIY Light Guide Plates

March 13, 2023 by 39 Comments

Last year, I found myself compelled to make a scaled-down replica of the iconic test chamber signs from the video game Portal. If you’ve played the game, you’ll remember these signs as the illuminated monoliths that postmarked the start of every test chamber. In hyperstylized video game fashion, they were also extremely thin.

Stay tuned for cake at the end of this article.

True to the original, my replica would need to be both slimmed down and backlit with a uniform, natural white glow. As fate would have it, the crux of this project was finding a way to do just that: to diffuse light coming in from the edges so that it would emit evenly from the front.

What I thought would be quick project ended up being a dive down the rabbit hole that yielded some satisfying results. Today, I’d like to share my findings and introduce you to light guide plates, one of the key building blocks inside of much of today’s backlit screen technology. I’ll dig into the some of the working principles, introduce you to my homebrew approach, and leave you with some inspirational source code to go forth and build your own. Continue reading “A Hacker’s Introduction To DIY Light Guide Plates” →

Daniel Valuch Chats About CERN’s High Caliber Hacking

March 3, 2023 by 9 Comments

For those of us who like to crawl over complex systems, spending hours or even days getting hardware and software to work in concert, working at places like NASA or CERN seems like a dream job. Imagine having the opportunity to turn a wrench on the Space Shuttle or the Large Hadron Collider (LHC) — not only do you get to spend some quality time with some of the most advanced machines ever produced, you can be secure in the knowledge that your work will further humanity’s scientific understanding of the universe around us.

Or at least, that’s what we assume it must feel like as outsiders. But what about somebody who’s actually lived it? What does an actual employee, somebody who’s had to wake up in the middle of the night because some obscure system has gone haywire and stalled a machine that cost taxpayers $4.75 billion to build, think about working at the European Organization for Nuclear Research? Continue reading “Daniel Valuch Chats About CERN’s High Caliber Hacking” →

How Hard Could It Be To Get Millions Of Phone Bills Right?

March 2, 2023 by 46 Comments

It may be a foreign concept to anyone who has never paid a dime for a phone call over and above the monthly service charge, but phone calls were once very, VERY expensive — especially long-distance calls, which the phone company ungenerously defined as anything more than a few towns away. Woe betide the 70s teen trying to talk to out-of-town friends or carry on a romance with anyone but the guy or girl next door when that monthly phone bill came around; did anyone else try to intercept it from the mailbox before the parents could see it?

While it seems somewhat quaint now, being charged for phone calls was not only a big deal to the customers, but to the phone company itself. The Bell System, which would quickly become a multi-billion dollar enterprise, was built on the ability to accurately meter the use of their service and charge customers accordingly. Like any engineered system, it grew and changed over time, and it had to adapt to the technologies and economic forces at the time.

One of the most interesting phases of its development was the development of Automatic Message Accounting (AMA), which in a very real way paved the way for the wide-open, worldwide, too-cheap-to-meter phone service we enjoy today.

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Move Over Steel, Carbon-Reinforced Concrete Is Here

February 28, 2023 by 62 Comments

Reinforced concrete is the miracle material which made possible so many of the twentieth century’s most iconic structures, but here in this century its environmental footprint makes it something of a concern. As part of addressing this problem, a team at TU Dresden in Germany have completed what is believed to be the world’s first building made with carbon-reinforced concrete, in which the steel rebar is replaced with carbon fiber.

New materials are always of interest here at Hackaday, so it’s worth reading further about the nature of the reinforcement. The carbon fiber is woven into a mesh, or as a composite material that mimics existing rebar structures. These two types of reinforcement can be combined in a composite to produce a concrete structure much lighter than traditional steel-reinforced ones. If you page through the architecture critic description, it’s this lightness which has enabled the curving structure of the Dresden building to be so relatively thin.

The carbon saving comes presumably in the lower energy cost from not smelting iron to make steel, as well as the need for less concrete due to the lightness. All we need now is a low-carbon replacement for Portland cement.

Want to know more about concrete reinforcement? We’ve got you covered.

Methane Pyrolysis: Producing Green Hydrogen Without Carbon Emissions

February 13, 2023 by 52 Comments

Generally, when we talk about the production of hydrogen, the discussion is about either electrolysis of water into oxygen and hydrogen, or steam methane reforming (SMR). Although electrolysis is often mentioned – as it can create hydrogen using nothing but water and electricity – SMR is by far the most common source of hydrogen. Much of this is due to the low cost and high efficiency of SMR, but a major disadvantage of SMR is that large amounts of carbon dioxide are released, which offsets some of the benefits of using hydrogen as a fuel in the first place.

Although capturing this CO2 can be considered as a potential solution here, methane pyrolysis is a newer method that promises to offer the same benefits as SMR while also producing hydrogen and carbon, rather than CO2. With the many uses for hydrogen in industrial applications and other fields, such as the manufacturing of fertilizer, a direct replacement for SMR that produces green hydrogen would seem almost too good to be true.

What precisely is this methane pyrolysis, and what can be expect from it the coming years?

Continue reading “Methane Pyrolysis: Producing Green Hydrogen Without Carbon Emissions” →

All About USB-C: Manufacturer Sins

February 7, 2023 by 85 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” →