Wireless Power Makes For Cable-Free Desk

Some people hate cables with a passion; others are agnostic and prefer cabled peripherals to having to stop and charge their mouse. [Matt] from DIYPerks has the best of both worlds with this wireless-powered, no-cable desk setup.

The secret is embedded within the plywood desk: an evaluation kit from Etherdyne Technologies, Inc consisting of a 100 W RF power supply and its associated power antenna looping around the desktop edge. The mechanism is similar to the inductive charging often seen on phones nowadays, but at higher frequency and larger scale, enabling power to be transmitted several feet (at least a meter) above the desktop.

The range is impressive (this isn’t the maximum), but the efficiency is not advertised.

The kit from ETI contained several PCB-coil receivers, which [Matt] built into a number of devices, including a lamp, heated cup, microphone, speakers, his mouse, keyboard, and even a custom base to run his monitor, which really shows the power these things can pull.

The microphone is a non-Bluetooth RF unit lovingly modified to studio quality, at least as far as we can tell on laptop speakers through YouTube’s compression. The speakers use a pair of Bluetooth modules to negotiate stereo sound while staying in sync. And before you ask “what about signal for the monitor?”– we have to inform you that was taken care of too, via a wireless HDMI dongle. Check it out in the video below.

Of course the elephant in the room here is power usage — there’s a 10 W base draw, and probably a big hit to efficiency vs cabled-everything– but we figure he gets partway to a pass on that by using a Frameworks mainboard instead desktop hardware. Indeed, a full analysis might show that the transmission efficiency of this system is no worse than the power to charge/discharge inefficiencies in a more conventional battery powered wireless setup.

While no wires is pretty clean, we’re not sure this beats the totally-hidden-in-the-desk PC [Matt] built last year in terms of minimalist aesthetic.  That Frameworks mainboard also likely lacks the power of his triple-screen luggable, but this was still an entertaining build.

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Invisible PC Doubles As Heated Seat

Some people really want a minimalist setup for their computing. In spite of his potentially worrisome housing situation, this was a priority for the man behind [Basically Homeless]: clean lines on the desk. Where does the PC go? You could get an all-in-one, sure, but those use laptop hardware and he wanted the good stuff. So he decided to hide the PC in the one place no one would ever think to look: inside his chair.  (Youtube video, embedded below.)

This chair has very respectable specs: a Ryzen 7 9800XD, 64GB of ram and a RTX 4060 GPU, but you’d never know it. The secret is using 50 mm aluminum standoffs between the wooden base of the seat and the chair hardware to create room for low-profile everything. (The GPU is obviously lying sideways and connected with a PCIe riser cable, but even still, it needed a low-profile GPU.) This assemblage is further hidden 3D printed case that makes the fancy chair donated from [Basically Homeless]’s sponsor look basically stock, except for the cables coming out of it. It’s a very niche project, but if you happen to have the right chair, he does provide STLs on the free tier of his Patreon.

This is the first time we’ve seen a chair PC, but desk PCs are something we’ve covered more than once, so there’s obviously a demand to hide the electronics. It remains to be seen if hiding a PC in a chair will catch on, but if nothing else [Basically Homeless] will have a nice heated seat for winter. To bring this project to the next level of minimalism, we might suggest chording keyboards in the armrests, and perhaps a VR headset instead of a monitor.

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A console is shown displaying a system’s startup information, followed by “Booting from Hard Disk …”, “Hello World!” in a green font, and “The keyboard is working!”

A Forth OS In 46 Bytes

It’s not often that we can include an operating system in a Hackaday article, but here’s the full 46-byte source of [Philippe Brochard]’s 10biForthOS in 8086 opcodes:

50b8 8e00 31d8 e8ff 0017 003c 0575 00ea
5000 3c00 7401 eb02 e8ee 0005 0588 eb47
b8e6 0200 d231 14cd e480 7580 c3f4

Admittedly, this is quite a minimal operating system. It’s written for the Intel 8086, and consists of a Forth implementation with only two instructions: compile (1) and execute (0). It can receive commands over a serial connection or from a keyboard. This allows a host computer to load more complex software onto it, one byte at a time. In particular, [Philippe] provides instructions for loading more advanced compilers, such as subleq-eForth for a more complete Forth implementation, or SectorC for C programming. He’s also written a 217-byte port of the OS to Linux Intel x64.

[Philippe] doesn’t take a strong stance on whether this should technically qualify as a Forth implementation, given that the base implementation lacks stacks, dictionaries, and the ability to define words. However, it does have an outer and inner interpreter, the ability to compile and execute code, and most importantly, “the simplicity and hacky feeling of Forth.”

[Philippe] writes that this masterpiece of minimalism continues the tradition of the minimal Forth implementations we’ve covered before. We’ve even seen Forth run on an Arduino.

Pico-mac-nano Fits Working Macintosh On Barbie’s Desk

Have you ever looked in a doll house and said “I wish those dolls had a scale replica of a 1984 Macintosh 128K that could be operated by USB?” — well, us neither, but [Nick Gillard] gives us the option with his 63mm tall Pico-mac-nano project.

As you might imagine, this project got its start with the RP2040-based Pico Mac project by [Matt Evans], which we covered

The collector’s edition will come with a lovely box, but what’s in it is still open source so you can make your own.

before. [Nick] saw that, built it, and was delighted by it enough to think that if the Mac could run on such tiny hardware, how small could build a fully-usable replica Mac? The answer was 63 mm tall– at 5.5:1, that’s technically under the 6:1 scale that Barbie operates on, but if we had such a dollhouse we’d absolutely put one of these in it. (You just know Barbie’s an Apple kind of girl.)

The size was driven by the screen, which is a 2″ TFT panel with 480 x 640 pixel native resolution. Here [Nick] cheats a tiny bit– rather than trying to rewrite the PicoMac to output 640 x 480 and rotate the screen, he keeps the screen in portrait mode and drives it at 480 x 342 px. Sure, it’s not a pixel-perfect output, but no LCD is going to be a perfect stand in for a CRT, and who is going to notice 32 pixels on a 2″ screen? Regardless, that set the height of the computer, which is built around the portrait display. A highly detailed, and to our eyes, accurate replica of the original Macintosh case was printed to fit the LCD, coming in at the aforementioned 63mm tall.

Unfortunately this means the floppy drive could not be used for micro SD access– there is an SD card reader on this unit, but it’s on the back, along with a USB-C port, which is roughly where the mouse and keyboard ports are supposed to be, which is a lovely detail. Also delightful is the choice of a CR2 lithium battery for power, which is a form factor that will look just a bit familiar if you’ve been inside one of these old Macs.

[Nick] has posted the 3D designs and modified pico mac firmware to a GitHub repository, but if you’re looking for a charming desk ornament and don’t have the time to build your own, he will also be selling these (both kits and fully assembled units) via 1bitrainbow, which is the most delightfully retro web store we’ve seen of late.

If Classic MacOS isn’t good enough for you, how about linux? You won’t enjoy it as much, but it will run on the RP2040.

A graph of download speeds is shown, with two triangular spikes and declines. Above the graph, the label “8 MB/s” is shown.

A Quick Introduction To TCP Congestion Control

It’s hard to imagine now, but in the mid-1980s, the Internet came close to collapsing due to the number of users congesting its networks. Computers would request packets as quickly as they could, and when a router failed to process a packet in time, the transmitting computer would immediately request it again. This tended to result in an unintentional denial-of-service, and was degrading performance significantly. [Navek]’s recent video goes over TCP congestion control, the solution to this problem which allows our much larger modern internet to work.

In a 1987 paper, Van Jacobson described a method to restrain congestion: in a TCP connection, each side of the exchange estimates how much data it can have in transit (sent, but not yet acknowledged) at any given time. The sender and receiver exchange their estimates, and use the smaller estimate as the congestion window. Every time a packet is successfully delivered across the connection, the size of the window doubles.

Once packets start dropping, the sender and receiver divide the size of the window, then slowly and linearly ramp up the size of the window until it again starts dropping packets. This is called additive increase/multiplicative decrease, and the overall result is that the size of the window hovers somewhere around the limit. Any time congestion starts to occur, the computers back off. One way to visualize this is to look at a graph of download speed: the process of periodically hitting and cutting back from the congestion limit tends to create a sawtooth wave.

[Navek] notes that this algorithm has rather harsh behavior, and that there are new algorithms that both recover faster from hitting the congestion limit and take longer to reach it. The overall concept, though, remains in widespread use.

If you’re interested in reading more, we’ve previously covered network congestion control in more detail. We’ve also covered [Navek]’s previous video on IPV5. Continue reading “A Quick Introduction To TCP Congestion Control”

LED Matrix Built For M.2 Interface

The M.2 slot is usually used for solid-state storage devices. However, [bitluni] had another fun idea for how to use the interface. He built an M.2 compatible LED matrix that adds a little light to your motherboard.

[bitluni] built a web tool for sending images to the matrix.
[bitluni] noted that the M.2 interface is remarkably flexible, able to offer everything from SATA connections to USB, PCI Express, and more. For this project, he elected to rely on PCI Express communication, using a WCH CH382 chip to translate from that interface to regular old serial communication.

He then hooked up the serial interface to a CH32V208 microcontroller, which was tasked with driving a 12×20 monochrome LED matrix. Even better, he was even able to set the microcontroller up to make it programmable upon first plugging it into a machine, thanks to its bootloader supporting serial programming out of the box. Some teething issues required rework and modification, but soon enough, [bitluni] had the LEDs blinking with the best of them. He then built a web-based drawing tool that could send artwork over serial direct to the matrix.

While most of us are using our M.2 slots for more traditional devices, it’s neat to see this build leverage them for another use. We could imagine displays like this becoming a neat little add-on to a blingy computer build for those with a slot or two to spare. Meanwhile, if you want to learn more about M.2, we’ve dived into the topic before.

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C64 on desk with NFC TeensyROM and game token

TeensyROM NFC Game Loading On The C64

When retro computing nostalgia meets modern wireless wizardry, you get a near-magical tap-to-load experience. It’ll turn your Commodore 64 into a console-like system, complete with physical game cards. Inspired by TapTo for MiSTer, this latest hack brings NFC magic to real hardware using the TeensyROM. It’s been out there for a while, but it might not have caught your attention as of yet. Developed by [Sensorium] and showcased by YouTuber [StatMat], this project is a tactile, techie love letter to the past.

At the heart of it is the TeensyROM cartridge, which – thanks to some clever firmware modding – now supports reading NFC tags. These are writable NTag215 cards storing the path to game files on the Teensy’s SD card. Tap a tag to the NFC reader, and the TeensyROM boots your game. No need to fumble with LOAD “*”,8,1. That’s not only cool, it’s convenient – especially for retro demo setups.

What truly sets this apart is the reintroduction of physical tokens. Each game lives on its own custom-designed card, styled after PC Engine HuCards or printed with holographic vinyl. It’s a tangible, collectible gimmick that echoes the golden days of floppies and cartridges – but with 2020s tech underneath. Watch it here.

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