Is This 12-layer PCB Coil The Next Step In Ferrofluid Displays?

November 12, 2021 by Dave Rowntree 21 Comments

[Applied Procrastination] is in the business of vertical ferrofluid displays, but struggles somewhat with the electromagnets available off the shelf and the proliferation of wiring that results. [Carl Bugeja] is in the business of making PCB coils, both with rigid and flex PCB substrates, so when the opportunity for a collaboration arose, [AP] jumped at the opportunity.

As [Simen from AP] mentions in the video after the break, they had considered using a large PCB with embedded coils for Fetch their ferrofluid display unit, but the possible magnetic field was just too weak, and attempting to crank up the amps, just overheats them. Some improvements were made, first sticking the coil PCB to a small disk of ferrous metal, which doubled up as a handy heatsink. Next, he tried adding a permanent magnet, which added a bit of bias field. Alone this was not enough to hold the ferrofluid in place, but with the coil powered, it was starting to look encouraging.

Much more progress was made when [Carl] sent over a new design of his, a 12-layer PCB coil. This obviously had a much larger field, but still not enough without the extra boost from permanent magnet.

[Simen] currently doesn’t think the PCB approach is quite there yet, and is looking for help to source PCB-mounted electromagnets of the wired variety. We would imaging prototyping with such a large 12-layer PCB would be rather prohibitively expensive anyway.

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M5Paper Gets Open Source Weather Display Firmware

November 12, 2021 by Tom Nardi 25 Comments

We know you like soldering irons, we’re quite fond of them ourselves. But the reality is, modular components and highly capable development boards allow the modern hardware hacker to get things done with far less solder smoke then ever before. In fact, sometimes all you need to finish your project is the right code.

Case in point, check out the slick electronic paper weather display that [Danko Bertović] shows off in the latest Volos Projects video. While it certainly fits the description of a DIY project, he didn’t have to put any of the hardware together himself. The M5Paper is an ESP32 development kit designed around a crisp 4.7″, 960 x 540 e-paper panel that includes everything from environmental sensors to an internal 1150 mAh battery. To make your handheld e-paper dreams come true, the only thing you need to provide is the software.

The weather display code provided by [Danko] should certainly get you going in the right direction. Now don’t get us wrong, there’s certainly no shame in just flashing his code to the device and plunking it on your desk. It’s a gorgeous looking interface, and we all know that a sprinkling of open source code is often all it takes to make a standard consumer device extraordinary. But by using the code he’s provided as a launching point, you can take this turn-key device and really make it your own.

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Three-Dimensional Design Yields Compact Seven-Segment Hex Displays

November 11, 2021 by Adam Zeloof 10 Comments

Computers, from the simplest to the most complex, aren’t very useful if they can’t provide feedback to a user. Whether that interface takes the form of a monitor, a speaker, or a simple LED, there’s almost always some kind of output. One of the most ubiquitous is the ever-present seven-segment display. They’re small, they’re easy to use, and, perhaps most important, they’re cheap.

While the displays themselves are relatively compact, they often require some sort of driver circuitry — something that translates a digit into voltage at the correct pins. These drivers can take up valuable space, especially on a breadboard, and can sometimes make using seven-segment displays cumbersome. Thankfully, [John Lonergan] has a great solution: driver boards that sit completely beneath the displays. His dual seven-segment hex display project was born out of necessity — he needed it for the breadboard CPU SPAM-1, which was getting a bit too bulky. Each module is two seven-segment displays atop a small PCB. Beneath the displays lives an 8-bit PIC microcontroller, which acts as a driver for both of the displays.

It’s so easy to restrict ourselves to thinking in two dimensions when working on electronic design — even designing multilayer PCBs often feels like working on several, distinct two-dimensional areas rather than one three-dimensional one. The concept of stacking components to save space, while fairly straightforward to implement, is a great example of the kind of problem-solving we love to see here at Hackaday. Of course, if you like the idea of 3D circuit design, you have to check out some of these incredible circuit sculptures we’ve featured in the past.

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Palm OS: Reincarnate

November 11, 2021 by Matthew Carlson 26 Comments

[pmig96] loves PalmOS and has set about on the arduous task of reimplementing PalmOS from scratch, dubbing it Pumpkin OS. Pumpkin OS can run on x86 and ARM at native speed as it is not an emulator. System calls are trapped and intercepted by Pumpkin OS. Because it doesn’t emulate, Palm apps currently need to be recompiled for x86, though it’s hoped to support apps that use ARMlets soon. Since there are over 800 different system traps in PalmOS, he hasn’t implemented them all yet.

Generally speaking, his saving grace is that 80% of the apps only use 20% of the API. His starting point was a script that took the headers from the PalmOS SDK and converted them into functions with just a debug message letting him know that it isn’t implemented yet and a default return value. Additionally, [pmig96] is taking away some of the restrictions on the old PalmOS, such as being limited to only one running app at a time.

As if an x86 desktop version wasn’t enough, [pmig96] recompiled Pumpkin OS to a Raspberry Pi 4 with a ubiquitous 3.5″ 320×480 TFT SPI touch screen. Linux maps the TFT screen to a frame buffer (dev/fb0 or dev/fb1). He added a quick optimization to only draw areas that have changed so that the SPI writes could be kept small to keep the frame rate performance.

[pmig96] isn’t the only one trying to breathe some new life into PalmOS, and we hope to see more progress on PumpkinOS in the future.

LEDBOY Is A Retro-Modern Handheld Game

November 11, 2021 by Lewin Day 3 Comments

Back in the 1970s, there were a few LED-based games on the market that were quickly superseded by the rise of LCDs and other fancier technologies. However, [grossofabian] wanted to recreate that classic style of game but with more modern hardware. The result is the LEDBOY, a colorful handheld game built in tribute to that era.

The handheld is based around the ATtiny 1614 microcontroller, driving a 10×10 array of NeoPixel Nano 2427 LEDs, named for their small 2.4 mm x 2.7 mm form factor. They’re RGB, too, so there’s lots of wonderful colors to play with.

Wrapped up in a neat enclosure with a rechargeable 130 mAh lithium-ion battery and some simple tactile buttons, it’s a tidy little handheld game console. Add in the CH340C chip for USB to serial duties, and it’s easy to program with the Arduino IDE, too.

Code is available on Github for those keen to take a closer look. Amusingly, the project bears a striking resemblance to a similarly-named build we featured just under 12 years ago. Time is a flat circle, and the video, my friends, is after the break.

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Build Your Own HV Capacitors

November 11, 2021 by Al Williams 28 Comments

Finding high voltage capacitors can be tricky. Sure, you can buy these capacitors, but they are often expensive and hard to find exactly what you want. [RachelAnne] needed some low-value variable capacitors that would work at 100 kV. So she made some.

Instead of fabricating the plates directly, these capacitors use laminations from a scrap power transformer. These usually have two types of plates, one of which looks like a letter “E” and the other just like a straight bar. For dielectric, the capacitors use common transparency film.

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Motorcycle Rally Computer Goes Open Source

November 11, 2021 by Adam Zeloof 6 Comments

Motorcycle rally racing is a high-speed, exciting, off-road motorsport that involves zipping across all types of terrain on two wheels. While riding, it’s extremely important for riders to know what’s coming up next — turns, straightaways, stream crossings, the list goes on. Generally, this is handled by a roadbook — a paper scroll that has diagrams of each turn or course checkpoint, along with the distances between them and any other pertinent information. Of course, this needs to be paired with a readout that tells you how far you’ve traveled since the last waypoint so you’re not just guessing. This readout usually takes the form of a rally computer, a device that can display speed, distance traveled, and course heading (and some of the fancier ones have even more data available).

A roadbook with commercially-available rally computers

Frustrated with the lackluster interface and high cost associated with most rally computers on the market, [Matias Godoy] designed his own back in 2017, and was quick to realize he had a potential product. After several iterations he brought his idea to market with a small initial run, which sold out in a few hours!

He then took some time to reflect on the successful campaign. He decided that rather than continue to churn out units, he would open-source the design to make it available to everybody and see what the community could come up with. He published all of his design files to GitHub, and wrote up a wonderful blog post documenting the entire design process, from inspiration and early prototypes to his decision to go open source.

[Matias]’s project, the Open Rally Computer (formerly the Baja Pro) packages neatly in a CNC-machined case and features a nice high-visibility LCD display, a built-in GPS receiver, and an ergonomic handlebar-mounted remote. The data is crunched by an ESP32 microcontroller, which also allows for WiFi-enabled OTA updates. The end result is a beautiful and useful device that was clearly designed with great care. Love the idea but not a rally racer? If street bikes are more your thing then fear not because there’s an open source digital dashboard out there for you too.