free

[Jim Matthews] submitted their Ham Radio foxhunt transmitter project for the 2025 One Hertz Challenge.

This is a clever Spartan build. In order to create a radio beacon for use in a “fox hunt” [Jim] combined a SR-T300 walkie talkie module with a phototransistor and oscillating LED circuit. The phototransistor and oscillating LED are secured face-to-face inside heat shrink tubing which isolates them from ambient light. When the LED flashes on the phototransistor powers the radio which transmits a tone in the UHF band.

A fox hunt is a game played by radio enthusiasts in which players use radio signals to triangulate and find a hidden beacon. [Jim]’s circuit is the beacon, and when it’s powered by a three volt CR2032 battery, it transmits a strong signal over several hundred yards at 433.5 MHz, within the amateur radio UHF band.

If you’re interested in radio beacons you might like to read about the WSPR beacon.

From Blog – Hackaday via this RSS feed

This week, both our top winners on the insightful side come in response to our post about DOGE and the disaster in Texas. In first place, it’s That Anonymous Coward with a reaction to the government’s response:

Devoting a large portion of a press conference to patting themselves on the back & praising the god emperor while parents are waiting for any fragment of information.

Governor telling parents perhaps they didn’t pray hard enough to save their kids.

Speaker of the House of Rep. all we can do is pray.

ICE Barbie blaming old systems.

Member of Congress blaming bureaucrats, trying to shore up it was the fault of anyone but the people alleged in charge & who are supposed to care about citizens.

Prayer is an amazing dodge for them being stupid worthless pieces of shit.

They made a decision to not have the most basic things required, sirens. Its a proven technology (when maintained) but to save a few bucks on a line item they stopped. People honestly don’t understand that the costs of a disaster with no real warning, are way higher than the few bucks it cost to have that sort of system.

Mind you they have a magical statewide Blue Alert to fire off everytime something bad happens to a cop, it can be 200 miles away from where you are but they push it to everyone. Databrokers know your location to within meters, but we don’t have an alert system that can target. Pushing for vouchers for ‘christian’ schools matters much more than public safety.

An agency that has been DOGEd, had their satellite data turned off, most of their operations the jeebus freaks don’t understand stopped b/c they must be wasteful are under attack by the jeebus freaks who tied their hands.

They go on and on about how much these things cost…

(from a meme I’ve posted before online, prolly drop it on my bluesky today too.)

Image with text on a black background.“Take my $1.37,” “I want my PBS,”“Take my $.46,” “I am all for federal funding of art programs,”“Take my $.46,” “I love my museums, colleges, and libraries,”“Take my $.11,” “I support developing minority businesses,”“Take my $.66,” “I am for entrepreneurship and innovation,”“Take my $1.60,” “I want us to export more goods overseas,”“Take my $0.43,” “I would like to see more American manufacturing,”“Take my $0.88,” “I think community policing needs vast improvement,”“Take my $1.48,” “I support programs for women,”“Take my $1.55,” “I believe in due process for all,”“Take my $0.48,” “We need a civil rights division in the justice department,”“Take my $0.38,” “I think we need to defend our Mother Earth,”“Take my $0.03,” “I know more work needs to be done for climate change,”“Take my $8.95,” “because we need more sustainable energy,”“Take my $2.71.” “because we should reduce our carbon footprint.”

“IF SAVING THESE PROGRAMS MEANS I’M OUT $22.36 A YEAR, I’M GOOD. NOW GIVE ME BACK THE $575 I PAY TO KEEP THE WAR MACHINE RUNNING AND THE $368 I PAY IN CORPORATE WELFARE TO BIG OIL AND WALMART.”

In second place, it’s CSMcDonald with a comment about the reliance on ExTwitter to issue official notices:

Notifications on Social Media are worthless

Posting emergency communications on a platform ran by algorithms that almost guarantee they won’t be seen until far after they’d be useful has got to be the biggest dereliction of duty a government can do.

Our county has e-mail and text weather alerts you can opt into. Nobody should rely on FB or ExTwitter or Mastodon, etc. for emergency alerts. And if your local government does you need to hold them accountable for tragedies like this.

For editor’s choice on the insightful side, we start out with an anonymous comment on that post offering more perspective on what happened:

This was almost entirely preventable

Speaking as someone who has trained professional rescuers in tactics and strategies, including incident command:

The NWS, despite the insanely stupid cuts made by DOGE, did its job, did it well, and did it in a timely manner. Texas officials failed to pay attention and to act immediately and decisively. The warning the NWS issued at 1:26 AM in an area with a history of severe flash flooding should have resulted in a full callout of every available person and vehicle, with the latter dispatched to a pre-determined list of locations that are (a) close to the Guadalupe River and (b) likely to be full of people in the middle of the night. Including: a summer camp that’s been there since forever and is well-known to everyone.

The river was rising at that time (1:26 AM), but the catastrophic increase in flow didn’t happen until around 5:15 AM — most of 4 hours later. [1] They had all that time to send firetrucks, buses, vans, anything that could carry people to higher ground. They didn’t even manage to get warnings out, e.g., every available local and state police car should have been on the roads nearest the river with full sirens and lights waking everyone up. They should have fired up the tornado sirens. They should have sent Jim Billy Bob and his friends and their high-clearance pickup trucks out to get anybody they could find and get them to higher ground. They should have called and texted every phone, repeatedly. And so on.

If local officials had done even a half-ass job they probably could have saved almost everyone.

[1] I know this because I pulled the data from the USGS gauge. At 1:30 AM river flow was 12 cubic feet/second — pretty much a trickle in a river that size. At 3:30 AM it was 279 CFS — still not very much for a river that size, about enough to float a canoe. At 5:15 AM it was 315 CFS, still not very much. And then all the water from upstream began arriving: an hour later, at 6:15 AM, flow was 118,000 CFS. So they had from 1:26 AM until 5:15 AM, a precious 3 hours and 49 minutes, and they squandered it.

Next, it’s That One Guy with a comment about Trump’s new video streaming service, and its promo material that mentions “…discredited legacy news channels that have squandered the trust of the American people”:

‘We can’t do journalism, we might offend a billionaire!’

The funny thing is that second half actually has a large amount of truth to it, however the reason they’ve been discredited and lost the trust of the public is not because they’ve been ‘pandering to the woke’ but because they went in the opposite directly entirely, refusing to call out abhorrent behavior from conservatives lest they be accused of ‘anti-conservative bias’ and instead turning themselves into nothing more than spineless PR agencies that will uncritically report whatever someone rich and/or powerful tells them.

Over on the funny side, things have finally picked up a little bit after the last few weeks, so although there weren’t a ton of funny comments, there’s enough for a full section! In first place, it’s some anonymous sarcasm about Trump’s general attitude about everything:

Trump is right and:

economists are wronglaw firms are wrongclimate scientists are wrongepidemiologists are wrongthe media is wrong**historians are wrong

Trump is a gift from God, the new messiah, and anyone who opposes him in any way is wrong.

In second place, we return to the post about DOGE and Texas, where Pixelation also had thoughts on the government’s response:

I read what Trump said, I was SHOCKED to learn that it was Biden’s fault!

For editor’s choice on the funny side, we’ve got two more comments from that post, both on the subject of the “thoughts and prayers” that seem to be in such ample supply after disasters like this. First, it’s That One Guy with an idea:

‘Nothing could be done’, says person who did nothing.

If prayers are so powerful for republicans how about a deal?

The obscenely rich get ‘thoughts and prayers’ going forward, and everyone else gets all that useless ‘money’ for things like public safety and assistance programs.

I know it’ll be hard for the public to lose out on the highly valuable ‘thoughts and prayers’ while being left with only millions/billions of funding, but as the republicans just showed the way to make america great is to do everything possible to help the people who need help the least, with the expectations that they’ll then lift everyone else with them.

Next, it’s an anonymous alternative proposal:

So, what is missing is a Department Of Prayer Efficiency.Musk, any spare time to lead this?

That’s all for this week, folks!

From Techdirt via this RSS feed

The Hurdy-Gurdy continues to worm its way into pole position as the hacker’s instrument. How else could you explain a medieval wheel fiddle being turned into a synthesizer? Move over, keytar — [Rory Scammell]’s Balfolk Boombox is the real deal.

It began life as MIDI-outputting SAMgurdy by [Sam Palmer], which we sadly missed covering (though we did feature a MIDI-gurdy a few years back) but this boombox does far more than just MIDI samples. In a sentence no one ever thought would be penned, this instrument puts a Eurorack on a Hurdy-Gurdy for the ultimate synthwave bardcore mashup. There’s an analog synth, there’s a drum machine, there’s modularity to do whatever [Rory] should desire. There are also sixteen sampled instruments available at the push of a button, including multiple analog Hurdy-Gurdies.

It is, as [Rory] says, “a gig in a box”. There’s no point trying to describe it all in words: it really must be heard to be believed, so check out the demo video embedded below, and if you’re hankering for more info, he produced a fifteen minute in-depth video and if you can’t get enough of the sound, here’s a demo with all 16 sampled instruments. We’re pretty sure one of them is the Sega soundfont, and the 8-bit samples are absolutely GameBoy.

How, exactly, we fell in love with the hurdy-gurdy has fallen into mystery, but we’ve been filling up the hurdy-gurdy tag lately, on your suggestions. This one is thanks to a tip from [Physics Dude] in a comment– thanks for that, by the way– and the tips line remains open if the internet has not finally been scoured of all content both hurdy and gurdy.

From Blog – Hackaday via this RSS feed

Normally when you hear the words “rope” and “dog” in the same sentence, you think about a dog on a leash, but in this robot dog, the rope is what makes it move, not what stops it from going too far. [Aaed Musa]’s latest project is CARA, a robotic dog made mostly of 3D printed parts, with brushless motors and ropes used to tie the motors and legs together.

In a previous post, we covered [Aaed Musa]’s use of rope as a mechanism to make capstan drives, enabling high torque and little to no backlash. Taking that gearbox design, tweaking it a bit, and using three motors, he was able to make a leg capable of moving in all three axes. He had to do a good deal of inverse kinematics math to get the leg moving around as desired; once he had the motion of a step defined, it was time to build the rest of the dog.

CARA is made primarily of 3D printed parts, with several carbon fiber tubes running its length for rigidity. The legs are all free to move not only forward and back but side to side some, as in a real dog. He uses 12 large brushless motors, as they provide the torque needed, and ODrive S1 motor controllers to control each one, controlled over CAN by a Teensy 4.1 microcontroller. There is also a small BNO086 IMU to sense CARA’s position relative to gravity, and a 24V cordless tool battery powers everything.

Once assembled, there was some more tuning of what type of motion CARA’s legs take while walking. There were a few tweaks to the printed parts to address some structural issues, and then a good deal more inverse kinematics math to make full use of the IMU, allowing CARA to handle inclines and make a much more natural movement style. [Aaed Musa] does a great job explaining his approach on his site as well as in the video below; we’re looking forward to seeing his future projects!

CARA isn’t alone on this site—be sure to check out the other robot dogs we’ve featured here.

From Blog – Hackaday via this RSS feed

From Phys.org - latest science and technology news stories via this RSS feed

[Jackson Studner] wrote in to let us know about his ESP32-based media server: Jcorp Nomad.

This project uses a ESP32-S3 to create a WiFi hotspot you can connect to from your devices. The hotspot is a captive portal which directs the user to a web-interface comprised of static HTML assets which are in situ with the various media on an attached SD card formatted with a FAT32 file system. The static HTML assets are generated by the media.py Python 3 script when the ESP32 boots.

This project exists because the typical Raspberry Pi media server costs more than an ESP32 does. The ESP32 is smaller too, and demands less power.

According to [Jackson] this ESP32-based solution can support at least four concurrent viewers. The captive portal is implemented with DNS and HTTP services from the ESP32. The firmware is an Arduino project that integrates a bunch of libraries to provide the necessary services. The Jcorp Nomad media template supports Books (in pdf files), Music (in mp3 files), and Movies and Shows (in mp4 files). Also there is a convention for including JPEG files which can represent media in the user-interface.

And the icing on the cake? The project files include STL files so you can 3D print an enclosure. All in all, a very nice hack.

From Blog – Hackaday via this RSS feed

[Jared] managed to find a professional FAA-certified flight simulator at an auction (a disassembled, partial one anyway) and wondered, what would it take to rebuild it into the coolest flight sim rig ever?

In a video, [Jared] gives a tour of the system and highlights the potential as well as pointing out challenges and drawbacks. Fortunately the system is of a modular design overall, and the motion control system is documented. The chassis and physical parts are great, but the avionics stack is a mixed bag with some missing parts and evidence of previous tinkering — that part being not quite so well documented.

Conceptually, a mid-tier gaming rig with a wraparound display will take care of the flight software part, and some custom electronics work (and probably a Raspberry Pi or three) will do for interfacing to various hardware elements. But a lot of details will need to be worked out in order to turn the pile of components into an entertaining flight sim rig, so [Jared] invites anyone who is interested to join him in collaborating on innovative approaches to the myriad little challenges this build presents.

We’ve seen the community pull off some clever things when it comes to flight sims, so we know the expertise is out there.

From Blog – Hackaday via this RSS feed

From Phys.org - latest science and technology news stories via this RSS feed

If you’re looking for a more open, unenclosed 3D printer design than a cubic frame can accommodate, but don’t want to use a bed-slinger, you don’t have many options. [Boothy Builds] recently found himself in this situation, so he designed the Hi5, a printer that holds its hotend between two cantilevered arms.The hotend uses bearings to slide along the metal arms, which themselves run along linear rails. The most difficult part of the design was creating the coupling between the guides that slides along the arms. It had to be rigid enough to position the hotend accurately and repeatably, but also flexible enough avoid binding. The current design uses springs to tension the bearings, though [Boothy Builds] eventually intends to find a more elegant solution. Three independent rails support the print bed, which lets the printer make small alterations to the bed’s tilt, automatically tramming it. Earlier iterations used CNC-milled bed supports, but [Boothy Builds] found that 3D printed plastic supports did a better job of damping out vibrations.[Boothy Builds] notes that the current design puts the X and Y belts under considerable load, which sometimes causes them to slip, leading to occasional layer shifts and noise in the print. He acknowledges that the design still has room for improvement, but the design seems quite promising to us.This printer’s use of cantilevered arms to support the print head puts it in good company with another interesting printer we’ve seen. Of course, that design element does also lend itself to the very cheapest of printers.

Thanks to [Keith Olson] for the tip!

From Blog – Hackaday via this RSS feed

[Kevin Cheung] likes to upcycle old soda cans into — well — things. The metal is thin enough to cut by hand, but he’d started using a manual die-cutting machine, and it worked well. The problem? The machine was big and heavy, weighing well over 30 pounds. The solution was to get a lightweight die cutter. It worked better than expected, but [Kevin] really wanted it to be more portable, so he stripped it down and built the mechanism into a new case.

The video below isn’t quite a “how-to” video, but if you like watching someone handcraft something with a lot of skill, you’ll enjoy it. It also might give you ideas about how you could use one of these cutters, even if you don’t bother building a nice case for it.

We’ve seen cutters that use computer control, but they aren’t inexpensive. They will, however, make the same kind of cuts. But these manual die cutters are very inexpensive, and you simply have to find a way to make the die. You can easily make them for cutting paper, and, with the right materials, you can make the kind you see in [Kevin]’s video, too.

We have to admit, carrying the gizmo into a public place seemed to make a lot of people happy. So maybe portability is a good goal. But either way, you can have some fun with a machine like that.

If you want to cut paper, these work great. If you want paper to make the cuts, we have just the thing for you.

From Blog – Hackaday via this RSS feed

Display technology has come a long way since the advent of the CRT in the late 1800s (yes, really!). Since then, we’ve enjoyed the Nixie tubes, flip dots, gas plasma, LCD, LED, ePaper, the list goes on. Now, there’s a new kid on the block — water.

[Steve Mould] recently got his hands on an OpenDrop — an open-source digital microfluidics platform for biology research. It’s essentially a grid of electrodes coated in a dielectric. Water sits atop this insulating layer, and due to its polarized nature, droplets can be moved around the grid by voltages applied to the electrodes. The original intent was to automate experiments (see 8:19 in the video below for some wild examples), but [Steve] had far more important uses in mind.

When [Steve]’s €1,000 device shipped from Switzerland, it was destined for greatness. It was turned into a game console for classics such as Pac-Man, Frogger, and of course, Snake. With help from the OpenDrop’s inventor (and Copilot), he built paired-down versions of the games that could run on the 8×14 “pixel” grid. Pac-Man in particular proved difficult, because due to the conservation of mass, whenever Pac-Man ate a ghost, he grew and eventually became unwieldy. Fortunately, Snake is one of the few videogames that actually respects the laws of classical mechanics, as the snake grows by one unit each time it consumes food.

[Steve] has also issued a challenge — if you code up another game, he’ll run it on his OpenDrop. He’s even offering a prize for the first working Tetris implementation, so be sure to check out his source code linked in the video description as a starting point. We’ve seen Tetris on oscilloscopes and 3D LED matrices before, so it’s about time we get a watery implementation.

Thanks to [deʃhipu] for the tip!

From Blog – Hackaday via this RSS feed

If you’ve worked with germanium transistors, you’ll know that many of them have a disappointingly low maximum frequency of operation. This has more to do with some of the popular ones dating from the earliest years of the transistor age than it does to germanium being inherently a low frequency semiconductor, but it’s fair to say you won’t be using an OC71 in a high frequency RF application. It’s clear that [Ken Yap]’s project is taking no chances though, because he’s using a vintage germanium transistor at a very low frequency — 1 Hz, to be exact.

The circuit is a simple enough phase shift oscillator that flashes a white LED, in which a two transistor amplifier feeds back on itself through an RC phase shift network. The germanium part is a CV7001, while the other transistor is more modern but still pretty old these days silicon part, a BC109. The phase shift network has a higher value resistor than you might expect at 1.8 MOhms, because of the low frequency of operation. Power meanwhile comes from a pair of AA cells.

We like this project not least for its use of very period passive components and stripboard to accompany the vintage semiconductor parts. Perhaps it won’t met atomic standards for timing, but that’s hardly the point.

This project is an entry in the 2025 One Hertz Challenge. Why not enter your own second-accurate project?

From Blog – Hackaday via this RSS feed