A Simple POV Globe Via APA102

January 10, 2020 by Lewin Day 30 Comments

POV builds come in all shapes and sizes, and typically rely on LEDs for their high light output and fast response time. With this in mind, [Great Scott] grabbed some LED strip off the shelf and set about whipping up a POV LED globe.

Being a spinning POV build, it’s necessary to consider how to get power to the rotating elements. [Great Scott] decided to go with a simple solution of putting a LiPo battery on the rotating assembly, which runs the LEDs and Arduino Nano at the heart of the operation. The LEDs in question are of the APA102 type, making them readily addressable and capable of a wide color gamut. It’s all spun by a simple brushed DC motor, running from a separate supply at the base of the platform.

It’s very much a hacker build, held together with duct tape and zipties. Despite this, it looks tidy when in operation, as all of the important hardware is hidden at the centre of the globe. There’s a bit of a vibration problem, but [Great Scott] reckons this can be fixed with some frame modifications.

We’d love to see the build run some more advanced operations, like a representation of the Earth, or some kind of sun clock. If you’re interested in learning more about POV displays, we’ve got the primer you need. Video after the break.

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Diurnal Reef Control Realistically Insolates Your Aquarium

January 3, 2020 by Gerrit Coetzee 14 Comments

[Phillip]’s project is not just great for learning new words, it also shows just how complex natural systems can be.

As we know from news around the word, reefs are delicate systems prone to damage from just about any imaginable threat. Escaped aquarium fish, sunscreen, and the wayward feet of well meaning tourists to name a few. So it’s no wonder that aquarium hobbyists sometimes go to incredible lengths to simulate the natural environments these creatures live in.

While [Phillip] is still tinkering with his designs for this project, we found the data he included really interesting. His goal is to be able to plug in any coordinate on the earth and have the lights replicate the location. That includes not just the sun, but also the light from the moon as many corals seem to only spawn during certain tides. Of course no LED is perfect so he’s even experimenting with putting light sensors under the water to provide a feedback loop to make it perfect.

We really like the ambition of this project and we hope he continues.

PoE Powers Christmas Lights, But Opens Up So Much More

December 31, 2019 by Jenny List 12 Comments

Addressable LEDs are a staple of homemade Christmas decorations in our community, as is microprocessor control of those LEDs. So at first sight [Glen Akins]’ LED decorated Christmas tree looks pretty enough, but isn’t particularly unusual. But after reading his write-up you’ll discover there’s far more to the project than meets the eye, and learn a lot about the technologies behind it that has relevance far beyond a festive light show.

The decoration is powered exclusively from power-over-Ethernet, with a PIC microcontroller translating Art-Net DMX-over-Ethernet packets into commands for the LED string. The control board is designed from the ground up and includes all the PoE circuitry, and the write-up gives a very thorough introduction to this power source that takes the reader way beyond regarding PoE as simply another off-the-shelf black box. Along the way we see all his code, as well as learn a few interesting tidbits such as the use of a pre-programmed EEPROM containing a unique MAC address.

So if your house has CAT5 wiring and you want an extra dimension to your festive splendour, you’ve officially got a whole year to build your own version. He’s featured here before, with his buzzer to break the Caps Lock habit.

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Addressable LED Strings In Your USB

December 24, 2019 by Lewin Day 4 Comments

WS2812Bs, or NeoPixels, or whatever else you call them brought full-color LEDs to maker projects a meter at a time in recent years. Hooked up to a microcontroller, they make creating vibrant, full-color glowables a cinch. They won’t work on their own though, and a some point you want to ditch the dev board and let the blinking stand on its own two feet. Enter the USB LED Otter.

This small square of PCB lets you plug an LED strip directly into a USB port. The PCB itself has four traces on the back that mate with any USB port, and three pads for soldering the strip’s ground, 5 V line, and data. An STM32F072 microcontroller serves as the brains of the operation, packing plenty of horsepower and full compatibility with USB 2.0.

Code is flashed to the chip over USB using Device Firmware Upgrade (DFU) and once written the strip can then be driven by jamming the string into a suitably powerful USB wall charger. The woman behind the build, [Jana Marie], has mentioned that Open Pixel Control could be implemented but that may be an exercise left to the reader.

It’s a useful little tool, and one that promises to do even more with a little more development. Whipping up a few boards should be an easy task for anyone with a reflow oven and a free weekend. Oh, and if you’re tired of the WS2812? There’s other addressable LEDs out there, too!

194 LED Ball Is Free-Form Soldering On Another Level

December 23, 2019 by Jenny List 20 Comments

We’ve all seen plenty of impressive free-form soldering in these pages, maybe some of us have even had a go ourselves. Using nothing but bare conductors, electronic components, and solder, complex and beautiful electronic sculptures can be created. But the latest free-form project from [Jiří Praus] takes the medium to a new level, as he’s taken no less than 194 bare surface-mount addressable LEDs and formed them into a perfect sphere supported by nothing more than soldered copper wire.

This feat was achieved with the aid of a 3D printed hemispherical jig with spaces for each LED, and each half was assembled in a marathon soldering session. Some significant fault-finding was required due to a few dry joints, and an ESP32 board and Li-Po cell were fitted in between the two halves as they were joined. The result is a triumph, a Christmas bauble like no other, and one which we aren’t sure we could manage to solder so well even on a good day.

If you recognise [Jiří ]’s work, it’s probably because we’ve featured several of his creations previously. It’s always difficult to pick a favorite, but the one which caught our eye the most was his fully functional freeform Arduino Uno.

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Optical Communication Using LEDs Alone

December 22, 2019 by Jenny List 53 Comments

We’re all used to the humble LED as a ubiquitous source of light, but how many of us are aware that these components can also be used as photodiodes? It’s something [Giovanni Blu Mitolo] takes us through as he demonstrates a simple data link using just a pair of LEDs and a couple of Arduinos. It’s a showing off his PJON networking layer, and while you’d need a bit more than a couple of LEDs on breadboards for a real-world application, we still think it’s a neat demonstration.

PJON itself is very much worth a look, being an implementation of a robust and error-tolerant network for Arduinos and other small microcontroller platforms. It has a variety of communication strategies for various different media, and as this LED demonstration shows, its strength is that it’s capable of working through media that other networks would balk at. Whether it’s controlling home automation through metal heating ducts or providing an alternative to LoRa at 433 MHz, it’s definitely worth a second look. We’ve mentioned it before, but remain surprised that we haven’t seen it more often since. Take a look, the video is below the break.

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Movie-Style Hacking With A Wall Of Glowing Hex

December 20, 2019 by Tom Nardi 21 Comments

Over the years, the media has managed to throw together some pretty ridiculous visual depictions of computer hacking. But perhaps none have gone as far down the road of obfuscation as The Matrix, where the most experienced hackers are able to extract information from a display of cascading green glyphs like a cyberpunk version of reading tea leaves. It’s absolutely ridiculous, with zero basis in reality.

Well, maybe not anymore. Taking a page from these outlandish visions of hacking, [Erik Bosman] has constructed a dedicated hex dump display out of fourteen segment alphanumeric LEDs that looks like it could be pulled from a movie set. But make no mistake, it’s more than just a pretty face. By cleverly varying the brightness of the individual characters, he’s managed to make his so-called “hexboard” completely usable despite the fact that everything’s the same color.

While he says the project is not quite at 100% yet, he’s already released the firmware, computer-side software, and even the PCB design files for anyone who might want to build their own version. Though as you might imagine, it’s quite a tall order.

The display is broken up into segments holding eight Houkem-5421 LED modules apiece, each with its own STM32F030F4 and two TC7258E LED controllers. The bill of materials on this one is a bit intimidating, but when the end result look this good it’s hard to complain.

To build a somewhat smaller version that also features a more retro vibe, you might consider doing something similar by chaining together vintage LED “bubble” displays.