If you’ve spent any time on two wheels, you’ve certainly experienced the woes of poor bicycle shifting. You hit the button or twist the knob expecting a smooth transition into the next gear, only to be met with angry metallic clanking that you try to push though but ultimately can’t. Bicycle manufacturers collectively spent millions attempting to remedy this issue with the likes of gearboxes, electronic shifting, and even belt-driven bikes. But Praxis believes to have a better solution in their prototype HiT system.

Rather then moving a chain between gears, their novel solution works by folding gears into or away from a chain. These gears are made up of four separate segments that individually pivot around an axle near the cog’s center. These segments are carefully timed to ensure there is no interference with the chain making shifting look like a complex mechanical ballet.

While the shift initialization is handled electronically, the gear folding synchronization is mechanical. The combination of electronic and mechanical systems brings near-instant shifting under load at rotational rates of 100 RPM. Make sure to scroll through the product page and watch the videos showcasing the mechanism!

The HiT gearbox is a strange hybrid between a derailleur and a gearbox. It doesn’t contain a clutch based gear change system or even a CVT as seen in the famous Honda bike of old. It’s fully sealed with more robust chains and no moving chainline as in a derailleur system. The prototype is configurable between four or sixteen speeds, with the four speed consisting of two folding gear pairs connected with a chain and the sixteen speed featuring a separate pair of folding gears. The output is either concentric to the input, or above the input for certain types of mountain bikes.

Despite the high level of polish, this remains a prototype and we eagerly await what Praxis does next with the system. In the meantime, make sure to check out this chainless e-drive bicycle.

hackaday.com/2025/04/17/bicycl…

If you had to guess, what do you think it would take to build an ocean-going buoy that could not only survive on its own without human intervention for more than two years, but return useful data the whole time? You’d probably assume such a feat would require beefy hardware, riding inside an expensive and relatively large watertight vessel of some type — and for good reason, the ocean is an unforgiving environment, and has sent far more robust hardware to the briny depths.

But as Wayne Pavalko found back in 2016, a little planning can go a long way. That’s when he launched the first of what he now calls Maker Buoys: a series of solar-powered drifting buoys that combine a collection of off-the-shelf sensor boards with an Arduino microcontroller and an Iridium Short-Burst Data (SBD) modem in a relatively simple watertight box.

He guessed that first buoy might last a few weeks to a month, but when he finally lost contact with it after 771 days, he realized there was real potential for reducing the cost and complexity of ocean research.

Wayne recalled the origin of his project and updated the audience on where it’s gone from there during his 2024 Supercon talk, Adventures in Ocean Tech: The Maker Buoy Journey. Even if you’re not interested in charting ocean currents with homebrew hardware, his story is an inspirational reminder that sometimes a fresh approach can help solve problems that might at first glance seem insurmountable.

DIY All the Way

As Dan Maloney commented when he wrote-up that first buoy’s journey in 2017, the Bill of Materials for a Maker Buoy is tailored for the hobbyist. Despite being capable of journeys lasting for several thousand kilometers in the open ocean, there’s no marine-grade unobtainium parts onboard. Indeed, nearly all of the electronic components can be sourced from Adafruit, with the most expensive line item being the RockBLOCK 9603 Iridium satellite modem at $299.

Even the watertight container that holds all the electronics is relatively pedestrian. It’s the sort of plastic latching box you might put your phone or camera in on a boat trip to make sure it stays dry and floats if it falls overboard. Wayne points out that the box being clear is a huge advantage, as you can mount the solar panel internally. Later versions of the Maker Buoy even included a camera that could peer downward through the bottom of the box.

Wayne says that first buoy was arguably over-built, with each internal component housed in its own waterproof compartment. Current versions instead hold all of the hardware in place with a 3D printed internal frame. The bi-level framework puts the solar panel, GPS, and satellite modem up at the top so they’ve got a clear view of the sky, and mounts the primary PCB, battery, and desiccant container down on the bottom.

The only external addition necessary is to attach a 16 inch (40 centimeter) long piece of PVC pipe to the bottom of the box, which acts as a passive stabilizer. Holes drilled in the pipe allow it to fill with water once submerged, lowering the buoy’s center of gravity and making it harder to flip over. At the same time, should the buoy find itself inverted due to wave action, the pipe will make it top-heavy and flip it back over.

It’s simple, cheap, and incredibly effective. Wayne mentions that data returned from onboard Inertial Measurement Units (IMUs) have shown that Maker Buoys do occasionally find themselves going end-over-end during storms, but they always right themselves.

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Like Space…But Wetter

The V1 Maker Buoy was designed to be as reliable as possible.
Early on in his presentation, Wayne makes an interesting comparison when talking about the difficulties in developing the Maker Buoy. He likens it to operating a spacecraft in that your hardware is never coming back, nobody will be able to service it, and the only connection you’ll have to the craft during its lifetime is a relatively low-bandwidth link.

But one could argue that the nature of Iridium communications makes the mission of the Maker Buoy even more challenging than your average spacecraft. As the network is really only designed for short messages — at one point Wayne mentions that even sending low-resolution images of only a few KB in size was something of an engineering challenge — remotely updating the software on the buoy isn’t an option. So even though the nearly fifty year old Voyager 1 can still receive the occasional software patch from billions of miles away, once you drop a Maker Buoy into the ocean, there’s no way to fix any bugs in the code.

Because of this, Wayne decided to take the extra step of adding a hardware watchdog timer that can monitor the buoy’s systems and reboot the hardware if necessary. It’s a bit like unplugging your router when the Internet goes out…if your Internet was coming from a satellite low-Earth orbit and your living room happened to be in the middle of the ocean.

From One to Many

After publishing information about his first successful Maker Buoy online, Wayne says it wasn’t long before folks started contacting him about potential applications for the hardware. In 2018, a Dutch non-profit expressed interest in buying 50 buoys from him to study the movement of floating plastic waste in the Pacific. The hardware was more than up to the task, but there was just one problem: up to this point, Wayne had only built a grand total of four buoys.

Opportunities like this, plus the desire to offer the Maker Buoy in kit and ready to deploy variants for commercial and educational purposes, meant Wayne had to streamline his production. When it’s just a personal project, it doesn’t really matter how long it takes to assemble or if everything goes together correctly the first time. But that approach just won’t work if you need to deliver functional units in quantities that you can’t count on your fingers.

As Wayne puts it, making something and making something that’s easily producible are really two very different things. The production becomes a project in its own right. He explains that investing the time and effort to make repetitive tasks more efficient and reliable, such as developing jigs to hold pieces together while you’re working on them, more than pays off for itself in the end. Even though he’s still building them himself in his basement, he uses an assembly line approach that allows for the consistent results expected by paying customers.

A Tale Well Told

While the technical details of how Wayne designed and built the different versions of the Maker Buoy are certainly interesting, it’s hearing the story of the project from inception to the present day that really makes watching this talk worthwhile. What started as a simple “What If” experiment has spiraled into a side-business that has helped deploy buoys all over the planet.

Admittedly, not every project has that same potential for growth. But hearing Wayne tell the Maker Buoy story is the sort of thing that makes you want to go dust off that project that’s been kicking around in the back of your head and finally give it a shot. You might be surprised by the kind of adventure taking a chance on a wild idea can lead to.

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hackaday.com/2025/04/17/superc…

Ed ecco a voi Sinistra per Israele (come già noto prezzolata da Netanyahu)

Cronaca. Ieri in un dibattito in Senato si è riunita la cosiddetta “Sinistra per Israele” con Ivan Scalfarotto (Iv), Lucio Malan e Piero Fassino, Sensi e Delrio, Alfredo Bazoli e Walter Verini, Lia Quartapelle e Marianna Madia, Enza Rando e Antonio Nicita, Simona Malpezzi e Sandra Zampa; Marco Carrai, da sempre vicino a Matteo Renzi, e console onorario di Israele e Raffaella Paita, Luciano Nobili, Silvia Fregolent di IV.
L’iniziativa voleva contrastare la mozione contro Israele di Conte del giorno prima che ha visto anche la partecipazione della Shlein.
Fassino, oltre a ricordare ai presenti con orgoglio che viene definito “il sionista di sinistra”, ha ricordato anche “che va bene dire due popoli due Stati, ma che la soluzione ad ora non è praticabile”, dicendo inoltre che molte delle strutture operative di Hamas sono costruite vicino a luoghi come gli ospedali, e dunque risultano “fatali” le vittime civili. Fatali, ha usato questo termine per giustificare le conseguenze genocidiarie delle bombe israeliane. Per la cronaca - leggo da un articolo di oggi sul FQ- “una donna dal pubblico è pure intervenuta per rivendicare il fatto che l’esercito israeliano “avverte sempre dei suoi obiettivi”. Fassino l’ha rassicurata sulle sue posizioni, la sala ha applaudito”.
Cosa dire? Niente di più, se non che nella sala non aleggiava profumo di Chanel, ma di carne umana bruciata.

(Cosimo Minervini)

Il ministro alla Camera ha precisato che "nei primi mesi del 2025 è cresciuta la puntualità di tutti i servizi ferroviari. A marzo l'Alta velocità segna l'82,8%, gli intercity 89,4% mentre sui regionali 91,3%"

Addirittura i regionali sono più puntuali dell'alta velocità...

Sarebbe bello capire che definizione di "puntualità" hanno usato per poter arrivare a questi numeri.