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.

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Three Way LED Bulb Gives Up Its Secrets

March 14, 2023 by 18 Comments

You’ve probably seen three-way bulbs. You know, the ones that can go dim or bright with each turn of a switch. [Brian Dipert] wondered how the LED version of these works, and now that he tore one apart, you can find out, too. The old light bulbs were easy to figure out. They had two filaments, one brighter than the other. Switching on the first filament provided some light, and the second gave off more light. The final position lit both filaments at once for an even brighter light.

LED or filament, three-way bulbs have a special base. While a normal Edison-base bulb has the threaded part as the neutral and a center contact for the live wire, a three-way bulb has an extra hot contact ring between the threaded part and the center contact. Obviously, a compatible LED bulb will need this same interface, but will work differently inside.

Inside the LED, [Brian] found two rings of LEDs that took the place of the filaments. He was able to identify all the ICs and devices on the board except one, an MT7712S. If you can read Mandarin, we think this is the datasheet for it.

We weren’t sure what [Brian] would find inside. After all, you could just sense which contacts had voltage and dim the LEDs using PWM. It probably wouldn’t take any less circuitry. LED lighting is everywhere these days, and maybe they don’t all work the same, but you have to admit, using two strings of LEDs is reasonably faithful to the old-fashioned bulbs.

Sometimes LED bulbs are different depending on where you buy them. We were promised LED bulbs would never burn out. Of course, they do, but you can usually scrounge some LEDs from them.

Classic Gaming With FPGA And ATX

March 14, 2023 by 5 Comments

Playing classic games, whether they are games from the golden age of arcades or simply games from consoles that are long out of production, tends to exist on a spectrum. At one end is grabbing a game’s ROM file, finding an emulator, and kludging together some controls on a keyboard and mouse with your average PC. At the other is meticulously restoring classic hardware for the “true” feel of what the game would have felt like when it was new. Towards the latter end is emulating the hardware with an FPGA which the open-source MiSTer project attempts to do. This build, though, adds ATX capabilities for the retrocomputing platform. Continue reading “Classic Gaming With FPGA And ATX” →

The Curious Etymology Of The Elements

March 13, 2023 by 34 Comments

It’s not often that the worlds of lexicography and technology collide, but in a video by the etymologist [RobWords] we may have found a rare example. In a fascinating 16-minute video he takes us through the origins of the names you’ll find in the periodic table. Here’s a word video you don’t have to be on the staff of a dictionary to appreciate!

Etymology is a fascinating study, in which the scholar must disentangle folk etymologies and mistaken homophones to find the true root of a word. Fortunately in the case of most elements they bear a name bestowed on them by the scientists who discovered them, so their etymologies are rarely in dispute.

The etymologies split neatly into categories, with among them such distinctions as Latin or Greek descriptions, places including the Swedish village of Ytterby which has more elements named after it than anywhere else, elements named for mythological figures, and those named for people.

He artfully skates over the distinction between aluminium and a curiously similar metal the Americans call aluminum, because etymologists are used to deflecting controversy when language differences colour, or even color, people’s emotions. Thank you, Noah Webster!

It’s an entertaining diversion for anyone with a love of both science and of language, and should remind us that the study of language has just as much scientific rigour in its research as any of those elements.

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Building A Communications Grid With LoRaType

March 13, 2023 by 33 Comments

Almost all of modern society is built around various infrastructure, whether that’s for electricity, water and sewer, transportation, or even communication. These vast networks aren’t immune from failure though, and at least as far as communication goes, plenty will reach for a radio of some sort to communicate when Internet or phone services are lacking. It turns out that certain LoRa devices are excellent for local communication as well, and this system known as LoraType looks to create off-grid text-based communications networks wherever they might be needed.

The project is based around the ESP32 platform with an E22 LoRa module built-in to allow it to operate within its UHF bands. It also includes a USB-based battery charger for its small battery, an e-paper display module to display the text messages without consuming too much power, and a keyboard layout for quickly typing messages. The device firmware lets it be largely automated; it will seek out other devices on the local mesh network automatically and the user can immediately begin communicating with other devices on that network as soon as it connects.

There are a few other upsides of using a device like this. Since it doesn’t require any existing communications infrastructure to function, it can be used wherever there are no other easy options, such as in the wilderness, during civil unrest where the common infrastructure has been shut down, or simply for local groups which do not have access to cell networks or Internet. LoRa is a powerful tool for these use cases, and it’s even possible to network together larger base stations to extend the range of devices like these.

The Nixie Clock From Outer Space

March 13, 2023 by No comments

Nixie clocks are nothing new. But [CuriousMarc] has one with a unique pedigree: the Apollo Program. While restoring the Apollo’s Central Timing Equipment box, [Marc] decided to throw together a nixie-based clock. The avionics unit in question sent timing pulses and a mission elapsed time signal to the rest of the spacecraft. Oddly enough, while it had an internal oscillator, it was only used during failures. It normally synched to the guidance computer’s onboard clock.

There is a detailed explanation of the unit, along with some of the ancillary equipment and panels. Much of what the output from the unit is driving counters to display timers, although some of the clocks drive other pieces of equipment, like the telemetry commutator, which time stamps each telemetry frame.

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A solar-powered device with a small LCD screen

Low Power Challenge: LCD Solar Creatures Live On Sunlight, Sleep At Night

March 13, 2023 by 8 Comments

With all those e-paper based projects doing the rounds these days, including in our Low Power Challenge, you’d almost forget that monochrome LCDs were the original ultra-low-power display. Without them, we wouldn’t have had watches, calculators and handheld games operating off button cell batteries or tiny solar panels back in the ’80s and ’90s. [Gabor] decided to build a set of gadgets with a 1990s LCD aesthetic, called LCD Solar Creatures. These cute little beasts live on nothing but solar power and provide some amusing animations on a classic seven-segment LCD screen.

The Creatures’ activity depends entirely on the amount of power that’s available to them. If their supercapacitors dip below 3.3 V, their micros enter a deep sleep state and do nothing except briefly flash an LED every now and then as a sign of life. When light hits the solar panel, the supercaps are charged up and the Creatures come to life and display a few basic stats. Once the caps hit 4.1 V, they really start their day and run a few programs, including a Game of Life-style simulation and an animation of Euclidean rhythms. Continue reading “Low Power Challenge: LCD Solar Creatures Live On Sunlight, Sleep At Night” →