Building A Flying Drone With A Single Propeller

Technically all that you need in order to make a drone fly is a single motor and single propeller, but realistically it becomes basically impossible to fly it at that point. In the case of helicopters you therefore need a second rotor somewhere to provide counterbalance to the first and to be able to steer.

There are of course a number of ways to make a drone fly with a single helicopter, but the compromise usually is to use very large propellers, as well as other mechanisms that make for a very large drone. This wasn’t good enough for [Joshua Bird] who wanted to have a very small, single propeller drone.

Key to making it work is not only a very high RPM, but also a hinged propeller hub that manipulates the  angle of the blades in such a way that both pitch and roll can be controlled if you react quickly enough. This turned out to be impossible using standard motor ESCs that do not directly measure the motor’s speed and position but rely on back EMF.

In the final prototype of the drone such details had to be measured directly, with super-fast adjustments to the motor’s speed only possible with custom controller code and a lot of trial and error. Even then the drone would often lose track of its position and crash once more. The solution there was to add an infrared beacon in the room and a sensor on the drone, to give it a fixed reference point.

You can find the project files so far on the GitHub project page, with upcoming changes to the drone design involving improvements like adding a scanner to the drone so that it can autonomously use features in its environment as fixed reference points. That way it might conceivably be able to fly outside as well, which would be quite exciting to see.

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2026 Retrocomputing Challenge: Oldputer Gives Old Eyes Relief With E-ink Display

Modern computers are towers of glass and metal with very few large deviations from one to another. Monitor A will go against B, except you can’t tell them apart unless they’re on. At least, that is, compared to how different the old bulky monitors look compared to the new. [Andrzej Górski] seems to agree with this sentiment with his Oldputer, a blast from the past.

[Andrzej Górski]’s inspiration came from one component, and the main component of the project, an old e-ink display. When life gives you one of the slowest versions of a display, there really isn’t too much else to do other than pair it with slow old computers of the past. From that inspiration, there isn’t entirely a whole lot to do other than throw in an ESP32 and some LEDs for indicator lights. Put all this into a fun case, and you get one pretty desk ornament for whatever information you wanna display.

If you want to replicate the past again, you might want to look for the project GitHub here. If you’re looking for something even older, check out the replica of the MCM/70!

Discovering SDRs Everywhere

To quote commenter [douyarou], “It’s like our little version of a Precambrian explosion”. A bunch of hackers have discovered, independently and building on each other’s work, software-defined radio (SDR) capabilities in more places than you can shake a stick at.

It all started with [Espargos] and [h0m3us3r] apparently independently discovering that the ESP32 family of chips had a “secret” debug mode that allowed direct access to the radio that’s normally used for WiFi. While the 2.4 GHz radio signal is almost always immediately converted into data by the MAC hardware, here they found a way to listen in upstream, to the raw IQ data.

Seeing this, folks were immediately inspired to find out if they could transmit as well. [marble] not only got transmit functionality working, but integrated the part in with the standard osmosdr data flow, which meant that a whole bunch of existing tools were ready to go. We didn’t know about it at the time, but apparently [jochenhammes] and [z1000biker] concurrently had their TX-capable hacks up and running: here and here.

At this point, folks have already started to use the capabilities for broadcasting digital TV signals, voice signals, FM Hell, and other hijinks. This reminds us of the early days of the RTL-SDR project, when a competent, if receive-only, SDR functionality was found in a bunch of USB TV-tuner dongles. Once the hardware capabilities were sussed out, people started writing all sorts of useful software, and it gave rise to all manner of radio projects, from simply poking at domestic wireless devices to tracking all the airplanes in the world as they fly by.

[Tom] and I were discussing this on the podcast, and he remarked that of course there are SDRs hidden everywhere there is a radio unit these days, and the question is just whether or not we could hack them into usability. And before the podcast was even finally edited, [Samson1te] told us about his find in the LR2021 LoRa chip. This is a radio that’s designed to be a radio, with 16-bit resolution, and covering lower frequencies from 150 MHz to 960 MHz.

Compared to the RTL-SDR revolution, this is all happening at incredible speed. Each of these hacks will enable us to use different slices of radio spectrum with different degrees of ease, but it’s clear that the cost of entry into playing around with digital radio has just dropped precipitously. We will see hundreds of new signals hacks in the next few months – the floodgates have been opened.

SolidCraft Is Parametric, Automation-friendly CAD For Desktop And Browser

If you’re looking to try a new, open source 3D modeling CAD suite, especially one with automation-friendly interfaces, take a look at SolidCraft. It’s under development but there’s support for all the usual features like sketches, solid modeling, and constraints as well as a full parametric feature timeline.

SolidCraft offers desktop, browser-based, headless CLI, and MCP interfaces.

A parametric timeline essentially means the model exists not as a single discrete object, but as the sum of a sequence of operations. One advantage of this is being able to set things up so that if one changes a value (like wall thickness), all the features that depend on that change automatically get rebuilt as a result. But there’s more!

Written entirely in Rust, SolidCraft can run as a desktop app or as a web app in a browser. Everything the user can do in SolidCraft is a command with JSON parameters, and it offers a built-in headless command line interface and even an MCP (Model Context Protocol) server built specifically to give AI agents a way to use the program, should one be interested in experimenting with that sort of thing.

SolidCraft is still in early development, but so far quite a few features seem to work as they should. Check out the development roadmap for details, and there’s a live online demo if you’re in the mood to click around and get a feel for things.

We have seen quite a few open-source, browser-based CAD efforts over the years and it’s encouraging to see developers continuing to explore fresh ideas and features in the CAD landscape.

Making One Fender From Another

There’s a tendency among cherished brands to licence their name and logo onto all sorts of novelty items in order to make a quick buck. Joining this trend is the guitar maker Fender, who have lent their name to a chopping board in the shape of their famous Telecaster. The existence of such a product seems to have been a direct challenge to [Not A Luthier], who promptly bought one and turned it into a real guitar. It’s a genuine Fender, but is it a genuine Fender guitar? Not really, but it’s an entertaining build.

The chopping board isn’t made of great material, instead it’s a set of strips of wood, we’re guessing probably bamboo or rubberwood, glued together. It’s robust, but noticeably thinner than the guitar whose shape it takes, and with a not-great finish. The build is not too different from any other electric guitar build we’ve seen, with the main challenge being that the bridge and pickups need spacers underneath them to compensate for the reduced thickness of the wood.

The video is below the break and makes for a soothing watch as an in-depth guitar build, complete with a moment of drilling all the way through the board and fabricating a plug to hide the evidence. The final guitar seems to sound alright, but we’re not guitarists so maybe a more practiced ear should judge. The genuine Fender logo is still proudly on it so it’s a Fender of sorts, but just like with the chopping board, it’s best value is in novelty.

Meanwhile if guitar builds are a thing, we’ve had a few in the past.

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TAKTO, Open Source Hand-Tracking Built Like LEGO

Hand tracking in VR/AR can add a substantial amount of immersion and added interactivity. Unfortunately, most camera based tracking suffers when fingers get covered, intertwined, or simply out of view of the headset’s camera. What’s even less common are methods of giving feedback to the user’s hands. [Sebastian Molano] saw these issues and decided if anyone was going to make an open-source solution, it was going to be him with his thesis on TAKTO.

Clear visuals show step-by-step assembly.

TAKTO aims to remove the prior issues mentioned with visual tracking by using magnetic encoders to tell where the device is and the finger’s position inside it. Actuators are able to pull on the fingers themselves to add even further information to the user. Of course, none of this is too crazy, as we have seen similar projects before. Where TAKTO stands out is the extent of the support outside of a one-off hand tracker.

TAKTO.one not only holds general information about the project itself, but also an entire digital twin of the live device. This console can give you a visual of using the glove and general status information. Documentation on how to assemble one for yourself is presented in clean visuals, which should make the build process painless.

Everything else about how to make the hand for yourself can be found on the project’s GitHub. The price tag is steep for the actuated version, though there is a sensing-only version for hand tracking, and most of the cost comes from the quality actuators used. If you want to look into implementing some usability into existing VR hardware, make sure to look at what Valve has released publicly!

The Trials And Tribulations Of Your First Badge

On the face of it, making an event badge should be an easy process. After all, most of us can hand-assemble a microcontroller, some buttons, a battery, and a screen. But anyone who has been involved in producing one will tell you, the difference between producing one or two, and making sure hundreds or even thousands appear on day one of the event fully working is enormous. [Nicholas Ficara] produced 1750 of his first badge for Canada’s Hack The North hackathon, and he’s shared the full story.

We’ve been involved with the gestation of more than one badge here at Hackaday, so we recognise some of his learning moments only too well. He approached it with a well-planned series of prototype and release candidate steps to catch the problems, which came in handy as there certainly were a few. Wrong footprints, misplaced components, power supply issues, and rotated parts were fixed, and eventually they were delivered in time. It’s good to see that they were well received and well used at the event.

If you’re thinking of doing a badge we can certainly recommend that you give this a read. A few years ago we wrote up the story of another badge whose creators put in some hard work to save it from a more serious part error.