DEC’s LAN Bridge 100: The Invention Of The Network Bridge

August 27, 2024 by Maya Posch 13 Comments

DEC’s LAN Bridge 100 was a major milestone in the history of Ethernet which made it a viable option for the ever-growing LANs of yesteryear and today. Its history is also the topic of a recent video by [The Serial Port], in which [Mark] covers the development history of this device. We previously covered the LANBridge 100 Ethernet bridge and what it meant as Ethernet saw itself forced to scale from a shared medium (ether) to a star topology featuring network bridges and switches.

Featured in the video is also an interview with [John Reed], a field service network technician who worked at DEC from 1980 to 1998. He demonstrates what the world was like with early Ethernet, with thicknet coax (10BASE5) requiring a rather enjoyable way to crimp on connectors. Even with the relatively sluggish 10 Mbit of thicknet Ethernet, adding an Ethernet store and forward bridge in between two of these networks required significant amounts of processing power due to the sheer number of packets, but the beefy Motorola 68k CPU was up to the task.

To prevent issues with loops in the network, the spanning tree algorithm was developed and implemented, forming the foundations of the modern-day Ethernet LANs, as demonstrated by the basic LAN Bridge 100 unit that [Mark] fires up and which works fine in a modern-day LAN after its start-up procedure. Even if today’s Ethernet bridges and switches got smarter and more powerful, it all started with that first LAN Bridge.

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Running Stock MS-DOS On A Modern ThinkPad

August 22, 2024 by Tom Nardi 33 Comments

It might seem like the days of MS-DOS were a lifetime ago because…well, they basically were. Version 6.22 of the venerable operating system, the last standalone release, came out back in 1994. That makes even the most recent version officially 30 years old. A lot has changed in the computing world since that time, so naturally trying to run such an ancient OS on even a half-way modern machine would be a waste of time. Right?

As it turns out, getting MS-DOS 6.22 running on a modern computer isn’t nearly as hard as you’d think. In fact, it works pretty much perfectly. Assuming, that is, you pick the right machine. [Yeo Kheng Meng] recently wrote in to share his experiments with running the final DOS release on his Intel-powered ThinkPad X13 from 2020, and the results are surprising to say the least.

To be clear, we’re not talking about some patched version of DOS here. There’s no emulator at work either. Granted [Yeo] did embrace a few modern conveniences, such as using a USB floppy drive emulator to load the disk images instead of fiddling with actual floppies, and installing DOS onto an external drive so as not to clobber his actual OS on the internal NVME drive. But other than that, the installation of DOS on the ThinkPad went along just as it would have in the 1990s.

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Portable Router Build: Finding An LTE Modem

August 19, 2024 by Arya Voronova 8 Comments

Ever want your project equipped with a cellular interface for a data uplink? Hop in, I have been hacking on this for a fair bit! As you might remember, I’m building a router, I told you about how I picked its CPU board, and learned some lessons from me daily-driving it as a for a bit – that prototype has let me learn about the kind of extra hardware this router needs.

Here, let’s talk about LTE modems for high data throughput, finding antennas to make it all work, and give you a few tips that should generally help out. I’d like to outline a path that increases your chances of finding a modem working for you wonderfully – the devices that we build, should be reliable.

Narrowing It Down

If you look at the LTE modem selection, you might be a little overwhelmed: Simcom, Qualcomm, uBlox, Sierra, Telit, and a good few other manufacturers package baseband chipsets into modules and adjust the chipset-maker-provided firmware. The modems will be available in many different packages, too, many of them solderable, and usually, they will be available on mPCIe cards too. If you want to get a modem for data connections for a project, I argue that you should go for mPCIe cards first, and here’s why.

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Portable Router Build: Picking Your CPU

August 13, 2024 by Arya Voronova 23 Comments

I want to introduce you to a project of mine – a portable router build, and with its help, show you how you can build a purpose-built device. You might have seen portable routers for sale, but if you’ve been in the hacking spheres long enough, you might notice there are “coverage gaps”, so to speak. The Pi-hole project is a household staple that keeps being product-ized by shady Kickstarter campaigns, a “mobile hotspot” button is a staple in every self-respecting mobile and desktop OS, and “a reset device for the ISP router” is a whole genre of a hacker project. Sort the projects by “All Time” popularity on Hackaday.io, and near the very top, you will see an OpenVPN &Tor router project – it’s there for a reason, and it got into 2014 Hackaday Prize semifinals for a reason, too.

I own a bunch of devices benefitting from both an Internet connection and also point-to-point connections between them. My internet connection comes sometimes from an LTE uplink, sometimes from an Ethernet cable, and sometimes from an open WiFi network with a portal you need to click through before you can even ping anything. If I want to link my pocket devices into my home network for backups and home automation, I can put a VPN client on my laptop, but a VPN client on my phone kills its battery, and the reasonable way would be to VPN the Internet uplink – somehow, that is a feature I’m not supposed to have, and let’s not even talk about DNSSEC! Whenever I tried to use one of those portable LTE+WiFi[+Ethernet] routers and actively use it for a month or two, I’d encounter serious hardware or firmware bugs – which makes sense, they are a niche product that won’t get as much testing as phones.

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Audio On Pi: Here Are Your Options

August 12, 2024 by Arya Voronova 37 Comments

There are a ton of fun Raspberry Pi and Linux projects that require audio output – music players, talking robots, game consoles and arcades, intelligent assistants, mesh network walkie-talkies, and much more! There’s no shortage of Pi-based iPods out there, and my humble opinion is that we still could use more of them.

To help you in figuring out your projects, let’s talk about all the ways you can use to get audio out of a Pi or a similar SBC. Not all of them are immediately obvious and you ought to know the ropes before you implement one of them and get unpleasantly surprised by a problem you didn’t foresee. I can count at least five ways, and they don’t even include a GPIO-connected buzzer!

Let’s rank the different audio output methods, zoning in on things like their power consumption, and sort them by ease of implementation, and we’ll talk a bit about audio input options while we’re at it.

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Forget Ship In A Bottle, How About Joule Thief In A Fuse Tube?

August 7, 2024 by Donald Papp 14 Comments

We love close-up pictures of intricate work, and [w] hits the spot with a tiny joule thief in a fuse case (social media post, embedded below) powered by an old coin cell from a watch. It’s so tiny!

Ethernet transformers contain tiny coils.

A joule thief is a sort of minimum-component voltage booster that can suck nearly every last drop of energy from even seemingly-drained batteries, and is probably most famously used to light LEDs from cells that are considered “dead”.

Many joule thief designs feature hand-wound coils, which is great for junk box builds but certainly becomes more of a challenge for a tiny build like this one.

We really like that [w] salvaged a miniscule coil from an Ethernet transformer, most of which look like blocky SMD components from the outside but actually contain tiny coils.

The joule thief has been the basis of plenty of hacks over the years, and it’s always nice to see new twists on the concept.

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D+ and D- wires from a USB cable connected to GPIO pins on the Pi Pico, using a female header plugged onto the jumper wires

Need A USB Sniffer? Use Your Pico!

August 3, 2024 by Arya Voronova 24 Comments

Ever wanted to sniff USB device communications? The usual path was buying an expensive metal box with USB connectors, using logic analyzers, or wiring devboards together and hacking some software to make them forward USB data.

Now, thanks to [ataradov]’s work, you can simply use a Pi Pico – you only need to tap the D+ and D- pins, wire them to RP2040’s GPIOs, and you can sniff communication between your computer and any low-speed (1.5 Mbps) or full-speed (12 Mbps) devices. On the RP2040 side, plug the Pico into your computer, open the virtual serial port created, and witness the USB packets streaming in – for the price of a Pico, you get an elegant USB sniffer, only a little soldering required.

[ataradov] also offers us a complete board design with a RP2040 and a USB hub on it, equipped with USB sockets that completely free us from the soldering requirement; it’s an open-source KiCad design, so you can simply order some sniffers made from your favourite fab! This project is a great learning tool, it’s as cheap and easy to make as humanly possible, and it has big potential for things like reverse-engineering old and new systems alike. Just couple this hack with another Pico doing USB device or host duty, maybe get up to date with USB reverse-engineering fundamentals, and you could make a Facedancer-like tool with ease.

Need to reach 480 Mbit/s? [ataradov] has a wonderful board for you as well, that we have covered last year – it’s well worth it if a device of yours can only do the highest speed USB2 can offer, and, it offers WireShark support. Want WireShark support and to use a Pico? Here’s a GitHub project by another hacker, [tana]. By now, merely having a Pi Pico gives you so many tools, it’s not even funny.