FlexLED Is A Unique Take On Persistence Of Vision

July 9, 2019 by 13 Comments

Many hackers have experimented with the persistence of vision effect. Whip around a bunch of LEDs, flash them at just the right times, and it’s possible to make images to appear to hang in the air. There’s plenty of ways to do this, whether by manually shaking the LEDs by hand, spinning them around, or even putting them on your bike wheels. [Carl Bugeja] went a different route, taking advantage of the possibilities created by flex PCBs.

[Carl]’s project goes by the name FlexLED. This aptly describes the build, which, in prototype form, mounts a single LED on the end of a flex PCB. The PCB itself has a pattern of traces creating a coil, which enable it to interact with magnetic fields more strongly. By passing the right current through the coil, the flexible PCB can be made to flap up and down, moving the LED on the end at a rapid rate. By then controlling the flashing of the LED, it’s possible to create a persistence of vision effect.

Currently fitted with only one LED, capable of 3 colors, the visual display of the FlexLED is somewhat limited. However, [Carl] reports the effect is more impressive in person than on camera, and is already working on plans to scale up the project to a multi-LED diplay.

POV technology can do some pretty impressive things – even volumetric displays are possible. If you’re working on something yourself, be sure to let us know. Video after the break.

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It’s NICER In Orbit

July 9, 2019 by 1 Comment

Given the sheer volume of science going on as the International Space Station circles above our heads every 90 minutes or so, it would be hard for any one experiment to stand out. ISS expeditions conduct experiments on everything from space medicine to astrophysics and beyond, and the instruments needed to do the science have been slowly accreting over the years. There’s so much stuff up there that almost everywhere you turn there’s a box or pallet stuck down with hook-and-loop fasteners or bolted to some bulkhead, each one of them doing something interesting.

The science on the ISS isn’t contained completely within the hull, of course. The outside of the station fairly bristles with science, with packages nestled in among the solar panels and other infrastructure needed to run the spacecraft. Peering off into space and swiveling around to track targets is an instrument with the friendly name NICER, for “Neutron Star Interior Composition Explorer.” What it does and how it does it is interesting stuff, and what it’s learning about the mysteries of neutron stars could end up having practical uses as humanity pushes out into the solar system and beyond.

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Soak Up The Sun With This 3D Printed Solar Harvester

July 9, 2019 by 31 Comments

At first glance, adding solar power to your project might seem easy. Get a photovoltaic panel, point it towards the big ball of burning gas in the sky, and off you go. But in reality, there’s a bit more to it than that. Especially when you’re trying to do something on a small scale. Without a rooftop full of panels pumping out power, you’ve got to take what you can get.

If you’re looking to power small electronic devices such as sensors with a single solar panel, [Vadim Panov] has put together a very concise write-up and video on building a low-cost solar harvester. It combines a relatively small photovoltaic panel, a charging circuit, and a battery for energy storage into a easily mountable package. He’s provided all the details necessary to create your own version, all you have to do now is come up with the application for it.

As far as the electronics go, this project is about as straightforward as it gets. The three watt panel is connected up to a simplistic charging circuit, which in turn feeds into a single 18650 cell. You might be wondering why a charge controller is even necessary in such a simple set up. One problem is that the output voltage of the panel is higher than that of the battery. You also need a blocking diode that will prevent the battery from discharging into the cell during the night or in cloudy conditions.

While the electronics might seem elementary to some readers, we think the 3D printed case alone is worth taking a look at. Not only has [Vadim] come up with a design that perfectly encloses the fragile solar panel and associated electronics, but in the video after the break, he also explains how the entire thing can be made waterproof with an epoxy coating. As 3D prints can have a tendency to be porous, this technique is definitely something you should file away mentally if you’ve been thinking of deploying a printed enclosure outdoors.

Whether you’re looking to power environmental sensors for as near a century as is technically possible or a portable OpenWRT router for mobile anonymity, these small solar panels hold a lot of promise if you know how to work around their limitations.

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The Saga Of 32-Bit Linux: Why Going 64-Bit Raises Concerns Over Multilib

July 9, 2019 by 137 Comments

The story of Linux so far, as short as it may be in the grand scheme of things, is one of constant forward momentum. There’s always another feature to implement, an optimization to make, and of course, another device to support. With developer’s eyes always on the horizon ahead of them, it should come as no surprise to find that support for older hardware or protocols occasionally falls to the wayside. When maintaining antiquated code monopolizes developer time, or even directly conflicts with new code, a difficult decision needs to be made.

Of course, some decisions are easier to make than others. Back in 2012 when Linus Torvalds officially ended kernel support for legacy 386 processors, he famously closed the commit message with “Good riddance.” Maintaining support for such old hardware had been complicating things behind the scenes for years while offering very little practical benefit, so removing all that legacy code was like taking a weight off the developer’s shoulders.

The rationale was the same a few years ago when distributions like Arch Linux decided to drop support for 32-bit hardware entirely. Maintainers had noticed the drop-off in downloads for the 32-bit versions of their distributions and decided it didn’t make sense to keep producing them. In an era where even budget smartphones are shipping with 64-bit processors, many Linux distributions have at this point decided 32-bit CPUs weren’t worth their time.

Given this trend, you’d think Ubuntu announcing last month that they’d no longer be providing 32-bit versions of packages in their repository would hardly be newsworthy. But as it turns out, the threat of ending 32-bit packages caused the sort of uproar that we don’t traditionally see in the Linux community. But why?

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New Part Day: The $15 ESP32 With Cellular

July 9, 2019 by 51 Comments

Cruise around AliExpress for long enough and you’ll find some interesting new hardware. The latest is the TTGO T-Call, an ESP32 breakout board that also has a cellular modem. Yes, it’s only a 2G modem, but that still works in a lot of places, and the whole thing is $15.

On board the TTGO T-Cal is the ESP-WROVER-B, the same module you all know and love that features a dual-core ESP running at 240 MHz with 4 MB of Flash and 8 MB of SRAM. Add to this WiFi and Bluetooth, and you have a capable microcontroller platform. Of note is that this board includes a USB-C port, ostensibly wired so that it behaves like a normal USB micro port. That’s neat, 2019 is the year USB C connectors became cheaper than USB micro connectors.

In addition to the ESP32 module, there’s also cellular in the form of a SIM800 module. This module has been around for a while and used in many, many cellular-connected projects and products like the ZeroPhone. This module is only a 2G module, and that’ll be going away shortly (if not already) in built-up areas, but this can serve as a building block for modules that have more Gees than a 2G module. That said, if you’re looking for a WiFi and cellular bridge for fifteen bucks, you could do a lot worse for a lot more money.

Rock, Paper, Neural Net

July 9, 2019 by 6 Comments

You might think the game of Rock Paper Scissors is just the random chance, but that’s not true. There is a strategy for Rock Paper Scissors, multiple ones in fact, and the best human players can consistently beat any Joe Schmoe off the street. But what about computers? [Paul] answered that question with a tiny little keychain dongle that can beat you at Rock Paper Scissors.

This is a neural network, and you need to train a neural network, so where did [Paul] get all that data? roshambo.me offers thousands of paper rock scissor games, and trained the network on more than 85,000 human games, along with about 10,000 simulated games. Rock Paper Scissors isn’t a complicated game at all, and the entire neural network is stored on an ATtiny1614 microcontroller. The calculations are done as floats, even. That’s how non-computationally intensive this project is.

Building a neural network is one thing, but putting it in a handy keychain enclosure is something else. This handsome device fits on a PCB just larger than a 2032 coin cell battery and is enclosed in a 3D printed case. The buttons are 3D printed as well, with some clever application of fiber optic as light pipes for the LEDs. The end result is something that is slightly better than random chance at Rock Paper Scissors and shows off some matrix programming skills. Check out the video below.

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Hacking The Pocket Operator

July 8, 2019 by 3 Comments

The number of easily usable and programmable microcontrollers is small, so when selecting one for a project there are only a handful of very popular, well documented chips that most of us reach for. The same can be said for most small companies selling electronics as well, so if you reach for a consumer device that is powered by a microcontroller it’s likely to have one of these few in it. As a result, a lot of these off-the-shelf devices are easy to hack, reprogram, or otherwise improve, such as the Robot Pocket Operator.

The Pocket Operator is a handheld, fully-featured synthesizer complete with internal speaker. It runs on a Cortex M3, a very popular ARM processor which has been widely used for many different applications, and features everything you would need for a synthesizer in one tiny package, including a built-in speaker. It also supports a robust 24-bit DAC/ADC and all the knobs and buttons you would need. And now, thanks to [Frank Buss] there is a detailed teardown on exactly how this device operates.

Some of the highlights from the teardown include detailed drawings of how the display operates, all of the commands for controlling the device, and even an interesting note about how the system clock operates even when the device has been powered off for a substantial amount of time. For a pocket synthesizer this has a lot to offer, even if you plan on using it as something else entirely thanks to the versatility of the Cortex M3.

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