Author: Bryan Cockfield

1708 Articles

Getting PCIe Working On The New Pi 5

November 8, 2023 by 36 Comments

After the Pi 4 released, a discovery was quickly made that the internals of the popular single-board computer use PCIe to communicate with each other. This wasn’t an accessible PCIe bus normally available in things like desktop computers for expansion cards, though; this seemed to be done entirely internally. But a few attempts were made to break out the PCIe capabilities and connect peripherals to it anyway, with varying levels of success. The new Pi 5 seems to have taken that idea to its logical conclusion and included a PCIe connector, and [George] is showing us a way to interface with this bus.

The bus requires the port to be enabled, but once that’s done it’s ready to be used. First, though, some support circuitry needs to be worked out which is why [George] is reverse engineering the system to see what’s going on under the hood. There are a few handshakes that happen before it will work with any peripherals, but with that out of the way a PCIe card can be connected. [George] removed the connector to solder wires to the board directly in order to connect a proper PCIe port allowing a variety of cards to be connected, in this case a wireless networking card and an old Firewire card. This specific build only allows Gen 1 speeds, but the bus itself supports faster connections in theory with better wiring and support circuitry.

While it might not be the prettiest solution, as [George] admits, it does a great job of showing the inner workings of this communication protocol and its use in the new, more powerful Raspberry Pi 5. This makes a lot of things more accessible, such as high-speed PCIe HATs allowing for a wide range of expansion for these popular single-board computers, which wouldn’t have been possible before. If you’re still stuck with a Pi 4, though, don’t despair. You can still access the PCIe bus on these older models but it’ll take a little bit more work.

Thanks to [CJay] for the tip!

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An Open-Source Ebike Motor Controller

November 8, 2023 by 18 Comments

DIY e-bikes are often easy to spot. If they’re not built out of something insane like an old washing machine motor, the more subtle kits that are generally used still stand out when compared to a non-assisted bike. The motors tend to be hub- or mid-drive systems with visible wires leading to a bulky battery, all of which stand out when you know what to look for. To get a stealthy ebike that looks basically the same as a standard bicycle is only possible with proprietary name-brand solutions that don’t lend themselves to owner repair or modification, but this one has at least been adapted for use with an open source motor controller.

The bike in use here is a model called the Curt from Estonian ebike builder Ampler, which is notable in that it looks indistinguishable from a regular bicycle with the exception of the small 36-volt, 350-watt hub motor somewhat hidden in the rear wheel. [BB8] decided based on no reason in particular to replace the proprietary motor controller with one based on VESC, an open-source electric motor controller for all kinds of motors even beyond ebikes. Installed on a tiny Arduino, it fits inside the bike’s downtube to keep the stealthy look and can get the bike comfortably up to around 35 kph. It’s also been programmed to turn on the bike’s lights if the pedals are spun backwards, and this method is also used to change the pedal assist level, meaning less buttons and other user-interface devices on the handlebars. Continue reading “An Open-Source Ebike Motor Controller” →

Reliving The Authentic 90s Linux Experience

November 8, 2023 by 65 Comments

Installing Linux on a modern PC has never been easier. There are tons of tools available that will nearly-automatically download your Linux distribution of choice, image a USB drive, and make it bootable so you can finally ditch your bloated, privacy-violating operating system and get the free performance boost that comes along with it. This wasn’t always the case, though. In the 90s you had to take a trip to a store (or library) and buy (or borrow) a boxed copy of some variety of Linux on floppy disk or CDs, and then install it on your own, often without the help of the Internet. [Action Retro] demonstrates this process for us so we don’t have to relive the pain ourselves.

Complete with a 90s-era Pentium machine enclosed in a beige case, this is really the full 90s experience. He’s found a boxed version of Red Hat version 5.2 with everything needed to get it up and running and, after a brief issue with the installer crashing because it couldn’t figure out the ZIP disk drive, had another era-appropriate experience by erasing the existing Windows 98 installation. This was before automatic partitioning tools were widely available, so it was a real risk for beginner Linux enthusiasts if they were trying to dual boot.

With the installation complete, the X window system still needed to be set up, as well as making sure the settings for the old CRT monitor were correct. With everything finalized, the system can really be explored. It includes out-of-the-box some software plenty of us would recognize today such as GIMP and some other software we might not, like Netscape Communicator. It’s a real time machine experience to get this operating system running on period-appropriate hardware, and a lot of features of modern Linux systems can still be seen especially if your modern distribution of choice still requires a lot of manual configuration during installation. Old operating systems aside, this machine might be capable of running a modern Linux distribution as well, provided it has something slightly newer than a 486.

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50-Year-Old Program Gets Speed Boost

November 7, 2023 by 19 Comments

At first glance, getting a computer program to run faster than the first electronic computers might seem trivial. After all, most of us carry enormously powerful processors in our pockets every day as if that’s normal. But [Mark] isn’t trying to beat computers like the ENIAC with a mobile ARM processor or other modern device. He’s now programming with the successor to the original Intel integrated circuit processor, the 4040, but beating the ENIAC is still little more complicated than you might think with a processor from 1974.

For this project, the goal was to best the 70-hour time set by ENIAC for computing the first 2035 digits of pi. There are a number of algorithms for performing this calculation, but using a 4-bit processor and an extremely limited memory of only 1280 bytes makes a number of these methods impossible, especially with the self-imposed time limit. The limited instruction set is a potential bottleneck as well with these early processors. [Mark] decided to use [Fabrice Bellard]’s algorithm given these limitations. He goes into great detail about the mathematics behind this method before coding it in JavaScript. Generating assembly language from a working JavaScript was found to be fairly straightforward.

[Mark] is also doing a lot of work on the 4040 to get this program running as well, including upgrades to the 40xx tool stack, the compiler and linker, and an emulator he’s using to test his program before sending it to physical hardware. The project is remarkably well-documented, including all of the optimizations needed to get these antique processors running fast enough to beat the ENIAC. We won’t spoil the results for you, but as a hint to how it worked out, he started this project using the 4040 since his original attempt using a 4004 wasn’t quite fast enough.

Toy Gaming Controller Makes The Big Leagues

November 1, 2023 by 5 Comments

Some of the off-brand video game consoles and even accessories for the major brands can leave a lot to be desired. Whether it’s poor build quality or a general lack of support or updates, there are quite a few things on the market not worth anyone’s time or money. [Jonathan] was recently handed just such a peripheral, a toy game controller originally meant for a small child, but upon further inspection it turned into a surprisingly hackable platform, capable of plenty of IoT-type tasks.

The controller itself was easily disassembled, and the functional buttons within were wired to a Wemos D1 Mini instead of the originally-planned ESP32 because of some wiring irregularities and the fact that the Wemos D1 Mini having the required amount of I/O. It’s still small enough to be sealed back inside the controller as well, powered by the batteries that would have powered the original controller.

For the software, [Jonathan] is using MQTT to register button presses with everything easily accessible over Wi-Fi, also making it possible to update the software wirelessly. He was able to use it to do a few things as proof-of-concept, including playing a game in PyGame and controlling a Sonos speaker, but for now he’s using it to control an LED sculpture. With something this easily modified, though, it would be pretty straightforward to use it instead for a home automation remote control, especially since it is already set up to use MQTT.

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Teensy Stands In For The Motorola 68k

October 31, 2023 by 24 Comments

While it might not seem like it today, there was a time in the not-too-distant past where Motorola was the processor manufacturer. They made chips for everything, but the most popular was arguably the 68000 or 68k. It’s still has a considerable following today, largely among retrocomputing enthusiasts or those maintaining legacy hardware. For those wanting to dip their toes into this world, this Motorola 68000 emulator created by [Ted Fried] may be the thing needed to discover the magic of these once-ubiquitous chips.

The emulator itself runs on a Teensy 4.1, a 32-bit ARM microcontroller running at 600 MHz — giving it enough computing power to act as a cycle-accurate emulator not only for the 68000 CPU but also the local bus interface, in this case for a Mac 512K. This capability also makes it a drop-in replacement for the 68000 in these older Macs and the original hardware in these computers won’t notice much of a difference. A few tricks are needed to get it fully operational though, notably using a set of latches to make up for the fact that the Teensy doesn’t have the required number of output pins to interface one-to-one with the original hardware.

While the emulator may currently be able to replace the hardware and boot the computer, there is still ongoing development to get every part of the operating system up and working. The source code is available on the project’s GitHub page though so any updates made in the future can be found there. And if you have a Mac 128k and still haven’t upgraded to the 512k yet, grab one of these memory switching modules for the upgrade too.

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PC Fan Controller Works On Most Operating Systems

October 27, 2023 by 13 Comments

For better or worse, most drivers for PC-related hardware like RGB components and fan controllers are built for Windows and aren’t generally of the highest quality. They’re often proprietary and clunky, and even if they aren’t a total mess they generally won’t work on Linux machines at all, or even on a headless setup regardless of OS. This custom fan controller, on the other hand, eschews the operating system almost entirely in favor of an open source fan controller board that can be reached over a network instead.

The project’s creator, [Sasa Karanovic], experimented with fan splitters to solve his problems, but found that these wouldn’t be the ideal solution given the sheer number of fans he wanted in his various computers, especially in his network-attached storage machine. For that one he wanted ten fans, with control over them in custom groups that would behave in certain ways depending on what the computer was doing. His solution uses two EMC2305 five-fan controller chip which communicates over I2C on a custom PCB with a RP2040 at the center. This allows the hardware to communicate with USB to the host computer for updating firmware and controlling over the network. There’s also a 1-wire and I2C bus exposed in case any external sensors need to be integrated into this system as well. To get power for all of those fans, the board uses a SATA connector to get power from the computer’s power supply.

With the PCB built and all of the connections to the host computer made, the custom board is able to control up to 10 fans in any custom configuration without needing a monitor or a driver since it is accessible over the network through an API. It’s also open-source so any changes to the firmware or hardware can easily be made for most air-cooled PC situations. If you’re less concerned about the internal case temperature and more concerned about all the heat your PC is dumping into a living space, you might want to look into venting your PC outside instead.

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