Author: Bryan Cockfield

1708 Articles

Raspberry Pi Becomes Secure VPN Router

September 16, 2024 by 20 Comments

OpenWRT is a powerful piece of open-source software that can turn plenty of computers into highly configurable and capable routers. That amount of versatility comes at a cost, though; OpenWRT can be difficult to configure outside of the most generic use cases. [Paul] generally agrees with this sentiment and his latest project seeks to solve a single use case for routing network traffic, with a Raspberry Pi configured to act as a secure VPN-enabled router configurable with a smartphone.

The project is called PiFi and, while it’s a much more straightforward piece of software to configure, at its core it is still running OpenWRT. The smartphone app allows most users to abstract away most of the things about OpenWRT that can be tricky while power users can still get under the hood if they need to. There’s built-in support for Wireguard-based VPNs as well which will automatically route all traffic through your VPN of choice. And, since no Pi router is complete without some amount of ad blocking, this router can also take care of removing most ads as well in a similar way that the popular Pi-hole does. More details can be found on the project’s GitHub page.

This router has a few other tricks up its sleeve as well. There’s network-attached storage (NAS) built in , with the ability to use the free space on the Pi’s microSD card or a USB flash drive. It also has support for Ethernet and AC1300 wireless adapters which generally have much higher speeds than the built-in WiFi on a Raspberry Pi. It would be a great way to build a guest network, a secure WiFi hotspot when traveling, or possibly even as a home router provided that the home isn’t too big or the limited coverage problem can be solved in some other way. If you’re looking for something that packs a little more punch for your home, take a look at this guide to building a pfSense router from the ground up.

Train Speed Signaling Adapted For Car

September 11, 2024 by 33 Comments

One major flaw of designing societies around cars is the sheer amount of signage that drivers are expected to recognize, read, and react to. It’s a highly complex system that requires constant vigilance to a relatively boring task with high stakes, which is not something humans are particularly well adapted for. Modern GPS equipment can solve a few of these attention problems, with some able to at least show the current speed limit and perhaps an ongoing information feed of the current driving conditions., Trains, on the other hand, solved a lot of these problems long ago. [Philo] and [Tris], two train aficionados, were recently able to get an old speed indicator from a train and get it working in a similar way in their own car.

The speed indicator itself came from a train on the Red Line of the T, Boston’s subway system run by the Massachusetts Bay Transportation Authority (MBTA). Trains have a few unique ways of making sure they go the correct speed for whatever track they’re on as well as avoid colliding with other trains, and this speed indicator is part of that system. [Philo] and [Tris] found out through some reverse engineering that most of the parts were off-the-shelf components, and were able to repair a few things as well as eventually power everything up. With the help of an Arduino, an I/O expander, and some transistors to handle the 28V requirement for the speed indicator, the pair set off in their car to do some real-world testing.

This did take a few tries to get right, as there were some issues with the power supply as well as some bugs to work out in order to interface with the vehicle’s OBD-II port. They also tried to use GPS for approximating speed as well, and after a few runs around Boston they were successful in getting this speed indicator working as a speedometer for their car. It’s an impressive bit of reverse engineering as well as interfacing newer technology with old. For some other bits of train technology reproduced in the modern world you might also want to look at this recreation of a train whistle.

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Misleading GPS, Philosophy Of Maps, And You

September 10, 2024 by 19 Comments

The oft-quoted saying “all models are wrong, but some are useful” is a tounge-in-cheek way of saying that at some level, tools we use to predict how the world behaves will differ from reality in some measurable way. This goes well beyond the statistics classroom it is most often quoted in, too, and is especially apparent to anyone who has used a GPS mapping device of any sort. While we might think that our technological age can save us from the approximations of maps and models, there are a number of limitations with this technology that appear in sometimes surprising ways. [Kyle] has an interesting writeup about how maps can be wrong yet still be incredibly useful especially in the modern GPS-enabled world. Continue reading “Misleading GPS, Philosophy Of Maps, And You” →

Mobile Coffee Table Uses Legs To Get Around

September 10, 2024 by 22 Comments

For getting around on most surfaces, it’s hard to beat the utility of the wheel. Versatile, inexpensive, and able to be made from a wide array of materials has led to this being a cornerstone technology for the past ten thousand years or so. But with that much history it can seem a little bit played out. To change up the locomotion game, you might want to consider using robotic legs instead. That’s what [Giliam] designed into this mobile coffee table which uses custom linkages to move its legs and get itself from place to place around the living room.

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Rescuing High-Res Displays From Older Macs

September 10, 2024 by 25 Comments

When Apple started rolling out its Retina displays, it multiplied the amount of pixels compared to their standard, non-Retina displays by four. This increased pixel density while keeping the standard screen size — idea for those needing a lot of detail for their work. But, as is common with Apple, using these displays outside of the Apple ecosystem can be quite a challenge. Retina displays have been around for about a decade now, though, with some third-party hardware able to break them free of their cage. This post details how [Kevin] liberated the 5K display from a 2017 iMac for more general use with support for USB-C.

The first step was to find a used iMac for the right price, and then sell off most of its parts to recoup most of the initial cost. That brought the cost of the panel itself to about $250. The key to getting the display working without all of the Apple hardware is the R1811 driver board, which can be had for around $300. A new 156 watt power supply was added to the mix, and [Kevin] also put in a few extras like a USB cable extension and a latching push-button which kills the display’s power. Additionally, he attempted to get the original iMac speakers working with this setup too, but none of his attempts resulted in anything close to quality sound so he’s mostly abandoned that extra feature for now.

With that all buttoned up, he has a 27″ 5K display with USB-C input for around $650 which is quite a deal. The MacRumors thread that [Kevin] added his project to currently has around 1,700 posts about similar builds too, so it can be a wealth of information for all kinds of models. As Apple drops support for their older machines, these displays will become more and more common and projects like these can keep a lot of e-waste out of the landfill while also providing decent hardware at a bargain price. Don’t just look for iMacs and MacBooks though; there’s a similar process to use various iPad displays for other things as well.

Large Language Models On Small Computers

September 7, 2024 by 6 Comments

As technology progresses, we generally expect processing capabilities to scale up. Every year, we get more processor power, faster speeds, greater memory, and lower cost. However, we can also use improvements in software to get things running on what might otherwise be considered inadequate hardware. Taking this to the extreme, while large language models (LLMs) like GPT are running out of data to train on and having difficulty scaling up, [DaveBben] is experimenting with scaling down instead, running an LLM on the smallest computer that could reasonably run one.

Of course, some concessions have to be made to get an LLM running on underpowered hardware. In this case, the computer of choice is an ESP32, so the dataset was reduced from the trillions of parameters of something like GPT-4 or even hundreds of billions for GPT-3 down to only 260,000. The dataset comes from the tinyllamas checkpoint, and llama.2c is the implementation that [DaveBben] chose for this setup, as it can be streamlined to run a bit better on something like the ESP32. The specific model is the ESP32-S3FH4R2, which was chosen for its large amount of RAM compared to other versions since even this small model needs a minimum of 1 MB to run. It also has two cores, which will both work as hard as possible under (relatively) heavy loads like these, and the clock speed of the CPU can be maxed out at around 240 MHz.

Admittedly, [DaveBben] is mostly doing this just to see if it can be done since even the most powerful of ESP32 processors won’t be able to do much useful work with a large language model. It does turn out to be possible, though, and somewhat impressive, considering the ESP32 has about as much processing capability as a 486 or maybe an early Pentium chip, to put things in perspective. If you’re willing to devote a few more resources to an LLM, though, you can self-host it and use it in much the same way as an online model such as ChatGPT.

It’s Spreadsheets All The Way Down For This 80s Handheld

September 5, 2024 by 9 Comments

Unlike the today’s consumer computer market, the 1980s were the wild west in comparison. There were all kinds of different, incompatible operating systems, hardware, and programs, all competing against one another, and with essentially no networking to tie everything together. Some of these products were incredibly niche as well, only running one program or having a limited use case to keep costs down. Such was the Convergent WorkSlate, a computer that ran only a spreadsheet with any programs also needing to be built into a spreadsheet.

Upon booting the device, the user is presented with a fairly recognizable blank spreadsheet, albeit with a now-dated LCD display (lacking a backlight) and a bespoke keyboard and cursor that wouldn’t have allowed for easy touch typing. The spreadsheet itself is quite usable though, complete with formatting tools and the capability to use formulas like a modern spreadsheet program would. It also hosted a tape deck for audio and data storage, a modem for communicating with other devices, and an optional plotter-style printer. The modem port is how [Old VCR] eventually interfaces with the machine, although as one can imagine is quite a task for a piece of small-batch technology from the 80s like this. After learning how to send and receive information, a small game is programmed into the machine and then a Gopher interface is built to give the device limited Internet connectivity.

The investigation that [Old VCR] goes into on this project to get this obsolete yet unique piece of hardware running and programmed to do other tasks is impressive, and worth taking a look at especially because spreadsheets like this aren’t Turing-complete, leading to a few interesting phenomenon that most of us wouldn’t come across in the modern computing world. Since only around 60,000 units were ever made it’s difficult to come across these machines, but if you want to take a look at the spreadsheet world of the 80s without original hardware you can still run Lotus 1-2-3 natively in Linux today.

Thanks to [Cameron] for the tip!