Fixing The Failure Of The Reevo

June 8, 2026 by 6 Comments

There are a lot of traditional features of a bike that rarely change. The spokes, the chain, and the inability for it to take off like a rocket, to mention a few. None of these are features of the Reevo, a bike that tried, and mostly failed, to innovate the traditional electric bike. [Berm Peak], an individual with more time on two wheels than the entire Reevo team ever had, tried his hand at fixing the Reevo’s many problems.

[Berm Peak] has had a go at the Reevo before, but this time he had to go a lot deeper. Before any real work could be done on the Reevo, the controller needed to be jailbroken since the only way to use most features required an app that wasn’t available. Surprisingly, the controller boards were found to be well labeled, and with some trial and error, the protocols could be reverse-engineered.

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Repairing A Apple PowerBook 150 With Serious Issues

June 7, 2026 by No comments

Sometimes you purchase an old device that is very cheap for a good reason. So too with the 1995 Apple PowerBook 150 that [Hugh Jeffreys] purchased for a single Aussie buck back in 2018. After finally taking it off the shelf recently, the issues are very apparent. Without even trying to turn it on, the visible damage ranges from the display that’s gone full vinegar with wolverine scratches, to the snapped hinge. Naturally the HDD also turned out to be dead.

Without a functioning display there was little point in continuing, so the disassembly started there, revealing many broken plastic clips. The cause of the vinegar symptom is the degrading polarizer, which with some finesse can be removed like a thick screen protector. Fortunately, here it’s put on top of the glass layer of the display, so after peeling it off the remaining glue can be safely dissolved and scraped away.

Inside the case the RTC battery was found to have started leaking, causing corrosion and damaging a variety of important traces for the keyboard and display. All of this damage seemed fixable, but after a while the damage was just too severe. Fortunately he was able to obtain a replacement for the affected daughter PCB, which allowed the display to come back to life, so that a new polarizer could be installed after cutting a large sheet down to size.

A replacement hinge was then printed in PETG and glued to the part of the lid where it had broken off, while snapped plastic clips were reinforced with glue where they had hung on. Finally, the IDE HDD was replaced with a CF card via an IDE adapter and the entire system reassembled.

Unfortunately [Hugh] wasn’t able to immediately source or create MacOS floppies with a version that the laptop wanted to install from, so that part couldn’t be tested yet, but there’s a good chance that this old PowerBook 150 has finally been cured of at least its biggest ills, without spending much more than the original asking price.

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Desalinating Seawater With Solar And No Brine

June 7, 2026 by 7 Comments

Although desalination is very commonly used these days to convert seawater into fresh water, one of the major disadvantages of current approaches is that commercial desalination plants produce a lot of brine, which has to be dumped somewhere ideally without causing major environmental issues. A new solar-thermal method as demonstrated by [Luheng Tang] et al. was published in Light: Science and Applications, with accompanying PR article.

This method is claimed to require no pre-treatment or leave brine, using special panels that wick water across their surface and then use solar radiation to distill this water. This differs from previous similar methods through a special surface treatment that prevents build-up of salts which would require cleaning or replacement.

The salts and other contaminants that would normally end up in the brine slough off these cells and can then be further processed to recover everything from plain table salt to lithium as well as gold, uranium and other substances of interest that are prevalent in seawater.

So far these self-cleaning cells have been tested with water from a number of oceans with a claimed 74% solar-to-vapor conversion efficiency and nearly 100% salt extraction. As always the challenge will be in scaling this up to industrial levels, but so far it looks promising.

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Hackaday Links: June 7, 2026

June 7, 2026 by No comments

Christopher Nolan’s The Odyssey isn’t hitting theaters for another month or so, but if you’re already planning your trip to the cineplex, you may want to check out this page on the movie’s website which lets you view the trailer in the six (!) different formats it’s being released in.

We don’t really have an opinion on the big-screen adaptation of the epic tale as a piece of media, but from a technical standpoint, it’s interesting to see how the viewing experience changes between the 70mm IMAX version with an aspect ratio of 1.43:1 and the 35mm cut at 2.39:1. Unfortunately, the website offers no way to approximate what the movie will look like once compressed, streamed over the Internet, and displayed on a cheap TCL TV, to say nothing of how the viewing experience will be impacted should you watch the movie on your phone by way of a series of short YouTube clips while going to the bathroom. Maybe Nolan is saving that for his next film.

If you head over to the movies in one of Waymo’s vehicles, you can feel a little better about the long-term ecological impact of your trip thanks to a recently announced partnership between the autonomous car maker and B2U Storage Solutions. Under the agreement, old batteries pulled from Waymo’s fleet of self-driving electric cars will get a second life as localized grid storage.

The idea is that batteries which no longer hold enough charge to power a robo-taxi should still have enough capacity to store the energy produced by renewable sources so it can be doled out later when the demand goes up. By installing these batteries in the cities that Waymo actually operates their vehicles in, they don’t have to worry about shipping them around either — they can just yank them out of the car, and wire them right into the grid. Of course, eventually the batteries will be too cooked to adequately perform in this role as well, but this should give them a few more productive years before they get torn down and scrapped.

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Bluetooth Gramophone Has Surprisingly Contemporary Roots

June 7, 2026 by 8 Comments

So you happen to have a gramaphone– maybe a big old Victrola/HMV, perhaps a Columbia– regardless of brand, it’s a big, beautiful conversation peice for your living room. It might not be the most practical listening device, since isnomuch as there is a vinyl renessance, it’s restricted to vinyl, not the old shellac 78s the these all-mechanical beasts were born for. [JGJMatt] decided to bring his gramophone into the 21st century, turning it into a bluetooth speaker without altering any of its original internals.

What’s really interesting is that this hack was once a commercial product– sort of. Back in the 1920s when everyone was listening to Jazz, the problem of ‘ what do I do with this massive gramophone cabinet when I’m not cutting a rug?’ was equally valid, and a solution was found: the Dulce-Tone Radio Speaker. A very weak speaker sits under the needle, turning the gramaphone mechanism into an amplifier for the radio. The very same concept, [JGJMatt] would work equally well in the 2020s with a bluetooth signal as in the 1920s with an AM one. There’s no demo video for this project, but you can hear how its 1920s inspiration sounded in the video below.

The driver for this device is made using a neodymium magnet and the voice coil from a 3W speaker. A 3D-printed needle-holder captures the gramophone’s needle– a much thicker and sturdier thing than the tiny diamond-tip you’d find on a modern turntable, we should note– and holds the magnet to it. The voice coil gets driven via a MH-M38 bluetooth module, and everything is held in a nice 3D-printed case along with the battery.

The hack is, of course, totally reversible: at any moment, you can remove the needle from this device and drop it on a 78 for some Jazz-era fun, or swap back for 21st century brainrot. If you happen to have some of those old shellac records and a modern turntable, note it takes more than the right RPM to get good sound. Continue reading “Bluetooth Gramophone Has Surprisingly Contemporary Roots” →

How Small Can You Make A C Executable?

June 7, 2026 by 32 Comments

It’s well known that the difference in executable size between a compiled binary and one hand-written in optimized assembler will be significant. The compiler brings in all manner of boilerplate whether it needs all of it or not, which is responsible for the extra space. [Weineng] has fallen down the rabbit hole of trying to make the smallest possible gcc-compiled C executable, and the resulting write-up is a fascinating read.

Surprisingly the smallest C program isn’t “Hello World”, but one which simply does nothing but return 0. This results in a binary weighing in at a surprisingly large 15,816 bytes — something which surely could be improved. There follows a set of clever compiler flags and bits of code manipulation to remove some debugging information, and strip out unnecessary stuff executed before void main().

At 13,632 bytes it’s still a little on the chunky side, so it’s time to examine what libraries it brings in. More compiler flags get it down to 8,704 bytes. Removing a code comment section and error handling with more flags takes it to 4,320 bytes. Then there’s code which dictates how memory is allocated, which brings it down to 400 bytes. That’s an impressive reduction!

Reading this as hardware people we maybe don’t have the elite knowledge of compiler flags it takes to manage something like this. But we’ve all at times had to reduce the size of a bit of software, so we’re sure some of the techniques used are going to be interesting to quite a few readers.

After all, even hardware people need to trim the fat at times.

LIPS Is An Open Source Sip-And-Puff Interface

June 7, 2026 by 4 Comments

Lots of us have– thanks to repetative stress injuries– developed mobility issues that we have to work around when using computers. Maybe it’s a trackball instead of a mouse, or a split keyboard, or mechanical keys with very specific force requirements– but those are small potatoes compared to people with such severe movement issues such as quadriplegia who need to fall back on things like a sip-and-puff device to control the computer with their mouths. Commercial options of course come with absurd price tags, but a DIY option is a different story. [DanielYordanov]’s L.I.P.S project can be built for only a couple percent of what the big boys want, and it’s fully-open source.

So you might think a sip-and-puff device is a two-bit interface, only slightly more advanced than the morse terminal we featured earlier. While Morse code might be an option, these devices also act as pointers, as the lips and chin can be used to point the mouthpiece. Thus there are a few sensors needed: a hall-effect joystick for pointing info, and one or more pressure sensors to detect the breathing interface for ‘clicks’. [Daniel] has single and dual-sensor versions, creating at minimum a four-button mouse. In reality this hardware can distinguish long and short pulses, or combinations of breath to run some nice macros. With operating-system features like an on-screen keyboard, L.I.P.S. can provide someone with digital freedom– and at a tiny fraction of the cost of a ‘real’ medical device.

Despite the DIY nature, for the end-user control and config is easy enough thanks to a webserial portal run on the CH552 that you can preview on the official website. Code, ki-cad and STL files are all on his GitHub repository. If you’re interested in the design process, we’ve embedded his video about that below.

Thanks to [Daniel] for the tip! Do you know of a hack to make life better for someone, disabled or otherwise? Send us a tip!

From one-handed typing to open-source prosthesis, this sort quality-of-life hack may be the best thing about our community. Continue reading “LIPS Is An Open Source Sip-And-Puff Interface” →