Open-Source Mid-Drive E-Bike Motor Has Lots Of Promise, And Hyphens

[Pedro Neves] has a mid-drive e-bike, but he doesn’t own it — not truly, since he can’t repair the motor unit. For a hacker to be in that position, there are only two options: crack the old one and make it your own, or build your own from scratch. [Pedro] built his own and is open-sourcing it on his website for everyone to play with. Right now, that’s .step files and a BOM, so you’ll need to watch the design/build video on YouTube below to get the full picture.

His choice of a motor from an old battery-powered angle grinder is both thrifty and environmentally friendly, so we approve. His goal of 25 km/h seems like a reasonable speed limit, but may still be too fast for some countries’ regulations— so do check the local rules if you’re going to build this. Making the most of 3D-printed components is also a choice that makes the project more accessible, but don’t worry — the bearing surfaces are all metal. That includes the clutch bearing that will let you pedal home if the battery dies or the motor craps out. Well, unless the printed plastic axle gives up the ghost, but that got replaced with a CNC version, so it’s all good. Unless you’ve got legs like Hercules, it ought to hold.

If that’s not DIY enough, you could always build the motor yourself. This mid-drive is also part of a larger project [Pedro] is working on for a whole cargo bike, as he details in his video, which is a worthy project we’ve seen other examples of before.

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ESP32-driven Roulette Wheel Could Have Used A 555, But That Didn’t Have WiFi

Sometimes you see a project and immediately, before going into the details, your mind throws up the old refrain: “coulda used a 555” — well, [Hulk] actually agrees when it comes to his ESP32-based, 3D printed roulette wheel. The first version did use a 555, but then feature creep kicked in and the final project ended up with an ESP32 instead. We’ve all been there.

The roulette wheel circuit is retained from the 555 version, with the ESP32 providing clock pulses instead of the venerable oscillator chip — it uses a pair of decade counters to create the chase effect of the LED around the wheel. With a handsome printed enclosure, [Hulk] could have stopped there, but then he’d have to keep track of scoring and the like manually like some kind of dark age peasant. It’s the 21st century, we have computers to to that for us!

Now, even though the ESP32 is still driving the LED chase via the decade counters, it can keep track of where the “ball” of light lands, and reports that via WiFi or serial. While it would have been an option to run the whole game on the ESP32. [Hulk] just has those values put into an SQL database on a server, which also runs the game front-end via PHP. The resulting web page lets two players make their bets and track their wins and losses over time. You can see that in action in the video embedded below.

Overkill? Sure, but we suspect [Hulk] already had the equipment and experience to make this the fastest way to get a playable game. There are easy ways to serve web content from an ESP32, but the easiest tool to use is always the one in your back pocket, right?

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MacSurf Hits 2.0 To Bring PowerPCs Back Online

There’s an interesting thing about retrocomputing — the moment that you realize your 25-year-old machine can do almost everything your average person uses a computer for. The problem is that the average person mostly uses a computer as an internet appliance, and the big missing piece for most old machines is hooking up to the modern internet. HTTPS is good to have, but isn’t so easy to implement when your browser gets megabytes of RAM instead of gigabytes.

That’s why MacSurf by [mplsllc] is so interesting, especially version 2.0 just released-– its explicit goal is to get as much of the modern web onto an OS 9 equipped PowerPC Macintosh as physically possible.

Before you get too excited– no, you won’t be hitting up YouTube.com or even GitHub. That’s just too big and bloated now, even if you can get past the HTTPS hurdle. You will, however, be able to access, say MacintoshGarden.org, whose out-of-order HTTPS certificates sent the last version for a tizzy. The forums at 68kMLA work, and threads load quickly thanks to the as-needed image loading added this version.

Other nice things added include a proper history and bookmark manager.  There’s still no tab support, but have you seen the modern web? You’re not fitting more than one webpage into RAM on a G3 no matter how hard you try. You can, however, download the web browser directly from the http-only MacSurf.org homepage.

We featured the first release of this netsurf-based browser, and have to admit we’re impressed with the speed of development. If you want a totally modern system on PPC instead of just an up-to-date browser, you might want to check out MorphOS.

A rail sprayer somewhere on Union Pacific tracks

White Rails Are The Infrastructure Hack We Didn’t Know We Needed

Railroads might be a nineteenth century technology, but they’re still the backbone of cargo transportation in the 21st century. They’ve also far from run out of innovation, including this one which really just sounds like a hack: painting the rails white to beat the heat.

In the old days, when rails were short and riveted together, this might have been unecesssary; all those joints allowed for a lot of flex. But when you have kilometers of continously welded rail, the thermal expansion starts to matter. A lot. Even if the rails haven’t bent and buckled from excess heat, their capacity goes down. Trains must therefore slow way, way down in hot weather, reducing the overall amount of freight the system can handle.

So, how do you cool the million miles of metal that holds a country together? Paint. Simple white paint sprayed on the side of the rails can bring down temperatures 11 °C (20 °F), according to the Union Pacific Railroad, the first to try this in North America. It might not surprise you that this technique is also being rolled out on the other side of the pond during this summer’s European heat waves. Indeed, it was invented there; the Italians have been doing it for many years now.

If you think reducing solar heat with white paint is good, you can do better than that with special formulations that end up cooler than ambient. It passive cooling also comes in fibre form.

DOOM Runs (slowly) In A IBM PC-Compatible CSS Sheet

Just when you thought we’d run out of things to port DOOM to, here comes [Ahmed Amer] with his CSS-DOS, a massive 300 MB CSS style sheet, that runs not just DOS, but Windows 1.0 and, of course, DOOM. The CSS sheet isn’t holding a DOOM port this time, though — it’s holding a full IBM PC compatible, with a simulated 8086, 640 kB of RAM, floppy and VGA controllers. Yes, in one style sheet. We did mention it was 300 MB, right?

CSS is not a very good programming language. It’s got functions and if statements nowadays, but it doesn’t really do programs in the usual sense. That is, lists of instructions that feed one into another. You can’t change a variable without jumping through hoops. The sort of static behavior you get from a CSS sheet actually matches hardware architecture better than software, which was the key insight [Ahmed] had to make the project possible. It’s still not easy, or elegant, or perhaps even sane, as you can find out from the excellent write-up he has describing how he pulled this off. We particularly like the interactive guide to the full mountain of madness that is the .css file.

Now, we admit that “runs DOOM” may be an exaggeration — even if the maddeningly massive CSS sheet ran an IBM-AT full speed, that hardware can’t handle the game at any playable speed. It doesn’t emulate at anything close to full speed, though. Because this is such a gratuitously weird hack, it only runs at two instructions per second. No, not FPS, instructions, as in at the CPU level. Well, it could be worse, at least it’s not clock ticks. Still, if you’re time-dilated enough you can wait the 3 weeks to boot DOS, and the 3 months to load a level, you can play DOOM at 0.0001 FPS.

Look, we didn’t make the rules — they say everything has to try and run DOOM. They don’t say everything has to run it well.

The OpenOscar Server in terminal, with Pidgin connected

AIM-ing For A More Open Platform Than Discord

Do you remember AIM? It may suprize you to hear that AOL’s instant messanger was actually supported all the way up to 2017– two years after Discord launched. Unlike Discord, AIM is a protocol, not a platform. Everything on your favourite Discord server is at the mercy of the corporate masters of said server; you can’t just spool up your own. Not so for AIM, as [Veronica] explains, both on her blog and in a YouTube video that we’ve embedded below.

The key is the fact that the AIM protocol isn’t locked into AOL’s now-defunct servers; it was reverse engineered in its prime for open-source messengers like Pidgin. You can host your own server, too, using the OpenOscarServer by [mk6i]. Even better, it’s not just AIM, but ICQ! In the sort of irony you only get in real life, the OpenOscar community does all its support on a Discord server. But then, they couldn’t hardly do it over AIM or ICQ these days.

For those of you who were too old or too young to get sucked into the 90s instant messenger craze, these protocols don’t just create chat rooms, that would be the even older Internet Relay Chat protocol, but usually worked more like SMS text messages. You have a contact list, and you send messages to your contacts via a server that acts as a hub. Once upon a time, that server was AOL’s, but now thanks to the OpenOscar project, it can be anybody’s computer. Of course, like texting, you can rope all of your contacts into one big group chat, and the protocol does support images and VOIP. (Which is starting to sound a lot like Discord.)

If you’re tired of your friend-group being at the mercy of American tech companies, [Veronica]’s blog post serves as a good guide to get you started running OpenOscarServer on a Linux system; she used a virtual private server but figures a Raspberry Pi ought to have enough grunt if you don’t have a huge number of people signed up.

For completeness, we should mention that while AOL pulled the plug on AIM nearly a decade back, ICQ, the other protocol supported by OpenOscarServer, lasted straight through until 2024.

Thanks to Keith Olson for the tip! Our tipsline is based on decentralized “electronic mail” technology that anyone can access.

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2026 Frikkin Lasers Challenge: Laser Bandsaw

Can you call it a bandsaw if it has neither band nor saw? [WeldingRod1] does, with his entry in the laser contest — a manually-controlled laser cutter that he’s dubbed a Laser Bandsaw. Some might quibble that it’s not actually sawing with the beam, and others will inevitably find the safety implications rather frightening. We think it’s a fun project and that [WeldingRod1] can call it what he wants, as long as he follows his own advice and keeps his laser goggles firmly on his precious vision orbs.

He has actually put some thought into what started as the physical manifestation of a joke in a podcast. The blue diode laser — a NUBM44 diode rated at 7 W — got a custom-made copper heatsink. It’s also got a hefty beam dump in the form of a stack of box knife blades. That’s very necessary to keep the beam from reflecting where it shouldn’t, especially when you consider this operates like a regular band saw: you turn it on, and it’s ready to cut. With only 7 W of laser power it can’t cut that much, mind you, but apparently it’s great on balsa wood and blasts black paint off like nobody’s business.

Now if this was our shop we’d probably want to put the laser diode onto some kind of CNC platform, be it Cartesian or SCARA. But we’ve seen that done many, many times and if you’ve got the motor skills this might be just the tool for you. There’s a pinout and STLs for the 3D printed frame on the project page if you’re interested. If not, why are you still here? The article is finished. Go make something lase and send it in. The deadline for the 2026 Frikkin Laser Contest is fast approaching!