Let’s think of the last time you sent data without wires. We’re not talking WiFi here, but plain optical signals. Free-space optical communication, or FSO, is an interesting and easy way to transmit signals through light beams. Forget expensive lasers or commercial-grade equipment; this video by [W1VLF] offers a simple and cheap entry point for anyone with a curiosity for DIY tech. Inspired by a video on weak signal sources for optical experiments, this project uses everyday components like a TV remote-control infrared LED and a photo diode. The goal is simply to establish optical communication across distances for under $10. Continue reading “Beam Me Up: Simple Free-Space Optical Communication”
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Running Power And Data Over Just Two Wires
When you’re hooking up equipment across a vehicle, you’re often stuck sending power and data to and from things like sensors or actuators. The more wires you have to run, the more hassle, so it’s desirable to get this number as low as possible. That’s an especially big deal in the world of cycling electronics, where every additional gram is considered a drawback. To this end, companies have developed two-wire methods of sending power and data together, and now, [Keith Wakeham] has devised his own way of doing so.
[Keith] was inspired by Shimano’s E-Tube system which is fairly fancy in its encoding schemes, but he went his own way. His concept relied on old-school On-Off Keying methods to take a signal and capacitively couple a signal into power lines. He explains the theory behind the method, and shares schematics that can be used to actually communicate over power lines. Then, he shows off the real hardware that he built to test the concept for himself.
The results? Good! [Keith] was able to maintain speeds of 57,600 bits/second even with an electrically-noisy gear motor operating on the lines. That’s more then enough for all kinds of applications.
If you’ve got your own data-over-powerline hacks, don’t hesitate to let us know. Continue reading “Running Power And Data Over Just Two Wires”
Hackaday Links: January 21, 2024
Have you noticed any apps missing from your Android phone lately? We haven’t but then again, we try to keep the number of apps on our phone to a minimum, just because it seems like the prudent thing to do. But apparently, Google is summarily removing apps from the Play Store, often taking the extra step of silently removing the apps from phones. The article, which seems to focus mainly on games, and has a particular bone to pick about the removal of RPG Wayward Souls, isn’t clear about how widespread the deletions are, or what exactly the reason behind the removals could be. But they sure are exercised about it, and rightly so since in some cases the deleted games have actually been paid for by the users, and Google pretty much says that if you think you’re getting a refund, think again. They make some interesting points, such as this being the very definition of larceny, while also acknowledging that in all likelihood Google has a get-out-of-jail-free card buried in some EULA somewhere permitting them to do exactly what they’re doing. Google’s gonna Google, right?
Radiochat Is A Simple LoRa Interface Over WiFi
LoRa is often talked about as a potentially useful solution for emergency communication. The problem is, few of us are running around with LoRa hardware on a day-to-day basis. Student [William Barkoff] designed the Radiochat device as a simple tool that could pair with virtually anything over WiFi, and allow it to send and receive LoRa messages.
Radiochat is based on the Raspberry Pi Pico W, and uses the microcontroller’s wireless hardware to communicate with other devices. It provides a WiFi network that devices like laptops or smartphones can connect to. The Pico serves up a simple web page which accepts text input. Type in a message and hitting enter and the Pico will command a LoRa radio module over SPI to send that message out over the airwaves. It can then be picked up by another Radiochat module which displays the message on its own webpage.
It’s in an early state of development, and the demo video shows there are still some bugs to work out. Ultimately, though, it could be a cheap battery-powered device that lets smartphones and laptops chat over LoRa in remote areas. Indeed, [William’s] trips to New Mexico on model rocketry expeditions were a big inspiration for the project.
Continue reading “Radiochat Is A Simple LoRa Interface Over WiFi”
Getting PCIe Working On The New Pi 5
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!
Cursive Out Loud: Dealing With Dragons
When we last left this broadening subject of handwriting, cursive, and moveable type, I was threatening to sing the praises of speech-to-text programs. To me, these seem like the summit of getting thoughts committed to what passes for paper these days.
A common thread in humanity’s tapestry is that we all walk around with so much going on in our heads, and no real chance to get it out stream-of-consciousness style without missing a word — until we start talking to each other. I don’t care what your English teacher told you — talking turns to writing quite easily; all it takes is a willingness to follow enough of the rules, and to record it all in a readable fashion.
But, alas! That suggests that linear thinking is not only possible, but that it’s easy and everyone else is already doing it. While that’s (usually) not true, simply thinking out loud can get you pretty far down the road in a lot of mental vehicles. You just have to record it all somehow. And if your end goal is to have the words typed out, why not skip the the voice recorder and go the speech-to-text route?
The TAK Ecosystem: Military Coordination Goes Open Source
In recent years you’ve probably seen a couple of photos of tablets and smartphones strapped to the armor of soldiers, especially US Special Forces. The primary app loaded on most of those devices is ATAK or Android Tactical Assault Kit. It allows the soldier to view and share geospatial information, like friendly and enemy positions, danger areas, casualties, etc. As a way of working with geospatial information, its civilian applications became apparent, such as firefighting and law-enforcement, so CivTAK/ATAK-Civ was created and open sourced in 2020. Since ATAK-Civ was intended for those not carrying military-issued weapons, the acronym magically become the Android Team Awareness Kit. This caught the attention of the open source community, so today we’ll dive into the growing TAK ecosystem, its quirks, and potential use cases.

Continue reading “The TAK Ecosystem: Military Coordination Goes Open Source”