Wireless Power Makes For Cable-Free Desk

June 8, 2025 by Tyler August 33 Comments

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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High-Stakes Fox Hunting: The FCC’s Radio Intelligence Division In World War II

June 4, 2025 by Dan Maloney 31 Comments

With few exceptions, amateur radio is a notably sedentary pursuit. Yes, some hams will set up in a national or state park for a “Parks on the Air” activation, and particularly energetic operators may climb a mountain for “Summits on the Air,” but most hams spend a lot of time firmly planted in a comfortable chair, spinning the dials in search of distant signals or familiar callsigns to add to their logbook.

There’s another exception to the band-surfing tendencies of hams: fox hunting. Generally undertaken at a field day event, fox hunts pit hams against each other in a search for a small hidden transmitter, using directional antennas and portable receivers to zero in on often faint signals. It’s all in good fun, but fox hunts serve a more serious purpose: they train hams in the finer points of radio direction finding, a skill that can be used to track down everything from manmade noise sources to unlicensed operators. Or, as was done in the 1940s, to ferret out foreign agents using shortwave radio to transmit intelligence overseas.

That was the primary mission of the Radio Intelligence Division, a rapidly assembled organization tasked with protecting the United States by monitoring the airwaves and searching for spies. The RID proved to be remarkably effective during the war years, in part because it drew heavily from the amateur radio community to populate its many field stations, but also because it brought an engineering mindset to the problem of finding needles in a radio haystack.

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Supercon 2024: How To Track Down Radio Transmissions

June 3, 2025 by Lewin Day 10 Comments

You turn the dial on your radio, and hear a powerful source of interference crackle in over the baseline noise. You’re interested as to where it might be coming from. You’re receiving it well, and the signal strength is strong, but is that because it’s close or just particularly powerful? What could it be? How would you even go about tracking it down?

When it comes to hunting down radio transmissions, Justin McAllister and Nick Foster have a great deal of experience in this regard. They came down to the 2024 Hackaday Superconference to show us how it’s done.

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Intercepting And Decoding Bluetooth Low Energy Data For Victron Devices

May 26, 2025 by John Elliot V 12 Comments

[ChrisJ7903] has created two Ardiuno programs for reading Victron solar controller telemetry data advertised via BLE. If you’re interested in what it takes to use an ESP32 to sniff Bluetooth Low Energy (BLE) transmissions, this is a master class.

The code is split into two main programs. One program is for the Victron battery monitor and the other is for any Victron solar controller. The software will receive, dissect, decrypt, decode, and report the data periodically broadcast from the devices over BLE.

The BLE data is transmitted in Link-Layer Protocol Data Units (PDUs) which are colloquially called “packets”. In this particular case the BLE functionality for advertising, also known as broadcasting, is used which means the overhead of establishing connections can be avoided thereby saving power.

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How To Build An STM32 Web Dashboard Using The Mongoose Wizard

May 25, 2025 by John Elliot V 2 Comments

Today from the team at Cesanta Software — the people who gave us the open-source Mongoose Web Server Library and Mongoose OS — we have an article covering how to build an STM32 web dashboard.

The article runs through setting up a development environment; creating the dashboard layout; implementing the dashboard, devices settings, and firmware update pages; building and testing the firmware; attaching UI controls to the hardware; and conclusion.

The web dashboard is all well and good, but in our opinion the killer feature remains the Over-The-Air (OTA) update facility which allows for authenticated wireless firmware updates via the web dashboard. The rest is just gravy. In the video you get to see how to use your development tools to create a firmware file suitable for OTA update.

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C64 on desk with NFC TeensyROM and game token

TeensyROM NFC Game Loading On The C64

May 23, 2025 by Heidi Ulrich 6 Comments

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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As The World Burns, At Least You’ll Have Secure Messaging

May 20, 2025 by Jenny List 45 Comments

There’s a section of our community who concern themselves with the technological aspects of preparing for an uncertain future, and for them a significant proportion of effort goes in to communication. This has always included amateur radio, but in more recent years it has been extended to LoRa. To that end, [Bertrand Selva] has created a LoRa communicator, one which uses a Pi Pico, and delivers secure messaging.

The hardware is a rather-nice looking 3D printed case with a color screen and a USB A port for a keyboard, but perhaps the way it works is more interesting. It takes a one-time pad approach to encryption, using a key the same length as the message. This means that an intercepted message is in effect undecryptable without the key, but we are curious about the keys themselves.

They’re a generated list of keys stored on an SD card with a copy present in each terminal on a particular net of devices, and each key is time-specific to a GPS derived time. Old keys are destroyed, but we’re interested in how the keys are generated as well as how such a system could be made to survive the loss of one of those SD cards. We’re guessing that just as when a Cold War spy had his one-time pad captured, that would mean game over for the security.

So if Meshtastic isn’t quite the thing for you then it’s possible that this could be an alternative. As an aside we’re interested to note that it’s using a 433 MHz LoRa module, revealing the different frequency preferences that exist between enthusiasts in different countries.

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