2025-05-10 07:00:40
Everyone knows what its like to get a hankering for a specific food. In [Attoparsec]’s case, he wanted waffles. Not any waffles would do, though; he needed waffles in the form of a labyrinth. Those don’t exist, so he had to machine his own waffle maker.
Most of us would have run this off on a CNC, but [Attoparsec] isn’t into CNCing–manual machining is his hobby, and he’s not interested in getting into another one, no matter how much more productive he admits it might make him. We can respect that. After a bit of brain sweat thinking of different ways to cut out the labyrinth shape, he has the opportunity to pick up an antique Deckle pantograph mill.
These machines were what shops used to do CNC before the ‘computer numeric’ part was a thing. By tracing out a template (which [Attoparsec] 3D prints, so he’s obviously no Luddite) complex shapes can be milled with ease. Complex shapes like a labyrnthine wafflemaker. Check out the full video below; it’s full of all sorts of interesting details about the machining process and the tools involved.
If you don’t need to machine cast iron, but are interested in the techniques seen here, a wooden pantorouter might be more your speed than a one-tonne antique. If you have a hankering for waffles but would rather use CNC, check out these design tips to help you get started. If pancakes are more your style, why not print them?
Shoutout to [the gambler] for sending this into the tip line. We think he struck the jackpot on this one. If you have a tip, don’t be shy.
2025-05-10 04:00:49
[Martin Lorton] has a vintage Harmon 4200B selective voltmeter that needed repair. He picked it up on eBay, and he knew it wasn’t working, but it was in good condition, especially for the price. He’s posted four videos about what’s inside and how he’s fixing it. You can see the first installment below.
The 4200B is an RMS voltmeter and is selective because it has a tuned circuit to adjust to a particular frequency. The unit uses discrete components and has an analog meter along with an LCD counter.
The initial tests didn’t work out well because the analog meter was stuck, so it wouldn’t go beyond about 33% of full scale.
Since there are four videos (so far), there is a good bit of information and detail about the meter. However, it is an interesting piece of gear and part 3 is interesting if you want to see inside an analog meter movement.
By the fourth video, things seem to be working well. You might want to browse the manual for the similar 4200A manual to get oriented.
Forgot why we measure RMS? You weren’t the only one. RMS conversion in meters is a big topic and there are many ways to do it.
2025-05-10 02:30:17
The Intel 8051 series of 8-bit microcontrollers is long-discontinued by its original manufacturer, but lives on as a core included in all manner of more recent chips. It’s easy to understand and program, so it remains a fixture despite much faster replacements appearing.
If you can’t find an original 40-pin DIP don’t worry, because [mit41301] has produced a board in a compatible 40-pin format. It’s called the single chip computer not because such a thing is a novelty in 2025, but because it has no need for the support chips which would have come with the original.
The modern 8051 clone in use is a CH558 or CH559, both chips with far more onboard than the original. The pins are brought out to one side only of the board, because on the original the other side would interface with an external RAM chip. It speaks serial, and can be used through either a USB-to-serial or Bluetooth-to-serial chip. There’s MCS-BASIC for it, so programming should be straightforward.
We can see the attraction of this board even though we reach for much more accomplished modern CPUs by choice. Several decades ago the original 8051 on Intel dev boards was our university teaching microcontoller, so there remains here a soft spot for it. We certainly see other 8051 designs, as for example this Arduino clone.
2025-05-10 01:02:37
When you’ve had some kind of injury, rehabilitation can be challenging. You often need to be careful about how you’re using the affected parts of your body, as well as pursue careful exercises for repair and restoration of function. It can be tedious and tiring work, for patients and treating practitioners alike.
Juan Diego Zambrano, Abdelrahman Farag, and Ivan Hernandez have been working on new technology to aid those going through this challenging process. Their talk at the 2024 Hackaday Supercon covers an innovative motion monitoring device intended to aid rehabilitation goals in a medical context.
As outlined in the talk, the team took a measured and reasoned approach to developing their device. The project started by defining the problem at hand, before proposing a potential solution. From there, it was a case of selecting the right hardware to do the job, and developing it alongside the necessary software to make it all work.
The problem in question regarded helping children through rehabilitative therapies. Structured activities are used to help develop abilities in areas like motor skills, coordination, and balance. These can be particularly challenging for children with physical or developmental difficulties, and can be repetitive at the best of times, leading to a lack of engagement. “We wanted to solve that… we wanted to make it more interactive and more useful for the therapies and for the doctors,” Ivan explains, with an eye to increasing motivation for the individual undergoing rehabilitation.
Other challenges also exist in this arena. Traditional rehabilitation methods offer no real-time feedback to the individual on how they’re performing. There is also a need for manual monitoring and record keeping of the individual’s performance, which can be tedious and often relies on subjective assessments.
Having explored the literature on game-based therapy techniques, the team figured a wearable device with sensors could aid in solving some of these issues. Thus they created their immersive motion rehabilitation device.
At the heart of the build is an Arduino Nano BLE33, so named for its Bluetooth Low Energy wireless communications hardware. Onboard is an nRF52840 microcontroller, which offers both good performance and low power consumption. The real benefit of this platform, though, is that it includes an inertial measurement unit (IMU) and magnetometer on board and ready to go. The IMU in question is the BMI270, which combines a high-precision 3-axis accelerometer and 3-axis gyroscope into a single package. If you want to track motion in three dimensions, this is a great way to do it.
For user feedback, some additional hardware was needed. The team added a vibration motor, RGB LED, and buzzer for this reason. Controlling the device is simple, with the buttons on board. In order to make the device easy to use for therapists, it’s paired with a Windows application, programmed in C#. It’s used for monitoring and analysis of the wearer’s performance during regular rehabilitation activities.
The talk explains how this simple, off-the-shelf hardware was used to aid the rehabilitation experience. By gamifying things, users are prompted to better engage with the therapy process by completing tasks monitored by the device’s sensors. Fun graphics and simple gameplay ideas are used to make a boring exercise into something more palatable to children going through rehabilitation.
The team go on to explain the benefits on the clinical side of things, regarding how data collection and real time monitoring can aid in delivery. The project also involved the creation of a system for generating reports and accessing patient data to support this work, as well as a fun connection assistant called Sharky.
Overall, the talk serves as a useful insight as to how commonly-available hardware can be transformed into useful clinical tools. Indeed, it’s not so different from the gamification we see all the time in the exercise space, where smartwatches and apps are used to increase motivation and provide data for analysis. Ultimately, with a project like this, if you can motivate a patient to pursue their rehabilitation goals while collecting data at the same time, that’s useful in more ways than one.
2025-05-10 00:00:31
This week, Hackaday’s Elliot Williams and Kristina Panos met up across the universe to bring you the latest news, mystery sound, and of course, a big bunch of hacks from the previous week.
In Hackaday news, the 2025 Pet Hacks Contest rolls on. You have until June 10th to show us what you’ve got, so head over to Hackaday.IO and get started today!
On What’s That Sound, Kristina actually got it this time, although she couldn’t quite muster the correct name for it, however at Hackaday we’ll be calling it the “glassophone” from now on. Congratulations to [disaster_recovered] who fared better and wins a limited edition Hackaday Podcast t-shirt!
After that, it’s on to the hacks and such, beginning with a complete and completely-documented wireless USB autopsy. We take a look at a lovely 3D-printed downspout, some DIY penicillin, and a jellybean iMac that’s hiding a modern PC. Finally, we explore a really cool 3D printing technology, and ask what happened to typing ‘www.’.
Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
Download in DRM-free MP3 and savor at your leisure.
2025-05-09 23:30:23
You’re designing an oscilloscope with modest storage — only 15,000 samples per channel. However, the sample rate is at 5 Gs/s, and you have to store all four channels at that speed and depth. While there is a bit of a challenge implied, this is quite doable using today’s technology. But what about in the 1990s when the Tektronix TDS 684B appeared on the market? [Tom Verbure] wondered how it was able to do such a thing. He found out, and since he wrote it up, now you can find out, too.
Inside the scope, there are two PCBs. There’s a CPU board, of course. But there’s not enough memory there to account for the scope’s capability. That much high-speed memory would have been tough in those days, anyway. The memory is actually on the analog board along with the inputs and digitizers. That should be a clue.
The secret is the ADG286D from National Semiconductor. While we can’t find any info on the chip, it appears to be an analog shift register, something all the rage at the time. These chips often appeared in audio special effect units because they could delay an analog signal easily.
In practice, the device worked by charging a capacitor to an input signal and then, using a clock, dumping each capacitor into the next one until the last capacitor produced the delayed output. Like any delay line, you could feed the output to the input and have a working memory device.
The scope would push samples into the memory at high speed. Then the CPU could shift them back out on a much slower clock. A clever design and [Tom] gives us a great glimpse inside a state-of-the-art 1990s-era scope.
While we haven’t seen the ADG286D before, we have looked at analog shift registers, if you want to learn more.
