Triangle Tiles Form Blinky Networks Using Clever Interconnects

We love to see LEDs combined in all shapes and sizes, so we were especially ticked when we caught a glimpse of [Debra Ansell]’s (also known as [GeekMomProjects]) interlocking triangular TriangleLightPanel system glowing on our screen. This unusually shaped array seemed to be self supporting and brightly glowing, so we had to know more.

The TriangleLightPanel is a single, triangular, light panel (refreshing when everything is in the name, isn’t it?).  Each panel consists of a single white PCBA holding three side-firing SK6812 LEDs aimed inward, covered by transparent acrylic. When the LEDs are doing their thing, the three-position arrangement and reflective PCB surface does diffuses the light sufficiently to illuminate each pane — if not perfectly evenly — very effectively. Given the simple construction it’s difficult to imagine how they could be significantly improved.

The real trick is the mechanical arrangement. Instead of being connected with classic Dupont jumper wires and 0.1″ headers or some sort of edge connector, [Debra] used spring contacts. But if you’re confused by the lack of edge-plated fingers think again; the connectors are simple plated strips on the back. There is a second PCBA which effectively acts as wires and a surface to mount the spring contacts on, which is bolted onto the back of the connected leaves to bridge between each node. The tiles need to be mechanically connected in any case, so it’s a brilliantly simple way to integrate the electrical connection with the necessary mechanical one.

All the requisite source files are available on the project’s GitHub page and the original Tweets announcing the project are here for reference. We can’t wait to see what this would look like with another 30 or 40 nodes! Enterprising hackers are already building their own setup; see [arturo182]’s 24 tile array glowing after the break.

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Magic Pyramids Blink Eternal With The Power Of The Sun

Without knowing it, we’ve spent years watching [Jasper Sikken] piece together an empire of energy harvesting equipment, and now he’s putting the pieces together into wonderful creations. His recently finished solar harvesting pyramids are mesmerizing objects of geometric perfection we’d love to see glinting in the sun.

These solar harvesting pyramids are well described by their name. Each one contains a PCBA around 30mm on a side with a solar energy harvester built around the dedicated AEM10941 IC, a single solar cell, and a very bright green LED. [Jasper] calculates that the solar cell will charge the super capacitor at 20uA at with just 200 lux of light (a level typical for casual indoor spaces) letting it run indefinitely when placed indoors. Amazingly with the LED blinking for 15ms every 2 seconds it will run for 21 days in complete darkness. And that’s it! This is a software-free piece of hardware which requires no input besides dim light and blinks an LED indefinitely.

Small PCBA, large capacitor

What about that super capacitor? It’s called a Lithium Ion Capacitor (LIC) and is a hybrid between a typical rechargeable lithium battery and an electrolytic capacitor, offering extremely high capacity in a convenient two leg through hole form factor. This one is a whopping 30 Farad at 3.8 V, and we first saw it when [Jasper] won the Hackaday Earth Day contest last month. Check out that link if you want to know more about their uses and how to integrate them.

For more detail about all of the components of the solar pyramid we need only turn to the Hackaday archives. In December 2019 [Tom Nardi] wrote about building a cheap degassing system for making some very familiar looking resin pyramids. And before that [Donald Papp] brought us another familiar piece of the pyramid when he wrote up a different 1″ x 1″ solar harvesting system that [Jasper] designed.

Check out the video after the break to see what one of these gems looks like from all sides. And for many more experiments leading up the final pyramid check out the logs on the Hackaday.io page.

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Otters Deliver A High Power Stationary Audio Experience

Our favorite raft of otters is back at it again with another display of open source audio prowess as they bring us the OtterCastAmp, the newest member of the OtterCast family of open source audio multitools. If you looked at the previous entry in the series – the OtterCastAudio – and thought it was nice but lacking in the pixel count or output power departments then this is the device for you.

The Amp is fundamentally a very similar device to the OtterCastAudio. It shares the same Allwinner S3 Cortex-A application processor and runs the same embedded Linux build assembled with Buildroot. In turn it offers the same substantial set of features and audio protocol support. It can be targeted by Snapcast, Spotify Connect or AirPlay if those are your tools of choice, or act as a generic PulseAudio sink for your Linux audio needs. And there’s still a separate line in so it source audio as well.

One look at the chassis and it’s clear that unlike the OtterCastAudio this is not a simple Chromecast Audio replacement. The face of the OtterCastAmp is graced by a luscious 340×800 LCD for all the cover art your listening ear can enjoy. And the raft of connectors in the back (and mountain of inductors on the PCBA) make it clear that this is a fully fledged class D amplifier, driving up to 120W of power across four channels. Though it may drive a theoretical 30W or 60W peak across its various outputs, with a maximum supply power of 100W (via USB-C power delivery, naturally) the true maximum output will be a little lower. Rounding out the feature set is an Ethernet jack and some wonderfully designed copper PCB otters to enjoy inside and out.

As before, it looks like this design is very close to ready for prime time but not quite there yet, so order at your own risk. Full fab files and some hints are linked in the repo mentioned above. If home fabrication is a little much it looks like there might be a small manufacturing run of these devices coming soon.

A HALO Of LEDs For Every Ear

Few things get a Hackaday staffer excited like bunches of tiny LEDs. The smaller and denser the better, any form will do as long as we can get a macro shot or a video of a buttery smooth animation. This time we turn to [Sawaiz Syed] and [Open Kolibri] to deliver the brightly lit goods with the minuscule HALO 90 reactive LED earrings.

The HALO 90’s are designed to work as earrings, though we suspect they’d make equally great brooches, hair accessories, or desk objects. To fit this purpose each one is a minuscule 24 mm in diameter and weighs a featherweight 5.2 grams with the CR2032 battery (2.1 g for the PCBA alone). Functionally their current software includes three animation modes, each selectable via a button on device; audio reactive, halo (fully lit), and sparkle. Check out the documentation for details on expected battery life in each mode, but suffice to say that no matter what these earrings will make it through a few nights out.

In terms of hardware, the HALO 90’s are as straightforward as you’d expect. Each device is driven by an STM8 at its maximum 16MHz which is more than fast enough to keep the 90 charliplexed 0402 LEDs humming along at a 1kHz update rate, even with realtime audio processing. In fact the BOM here is refreshingly simple with just 8 components; the LEDs, microcontroller and microphone, battery holder and passives, and the button. [Sawaiz] even designed an exceptionally slick case to go with each pair of earrings, which holds two HALO 90’s with two CR2032’s and includes a magnetic closure for the most satisfying lid action possible.

As with some of his other work, [Sawaiz] has produced a wealth of exceptional documentation to go with the HALO 90’s. They’re available straight from him fully assembled, but with documentation this good the path to a home build should be well lit and accessible. He’s even chosen parts with an eye towards long availability, low cost, and ease of sourcing so no matter when you decide to get started it should be a snap.

It was difficult to choose just a few images from [Sawaiz]’s mesmerizing collection, so if you need more feast your eyes on the expanded set after the break.

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New Part Day: Espressif ESP32-C6 Includes WiFi 6 And A RISC-V Core

If you’re a reader of Hackaday, then you’ve almost certainly encountered an Espressif part. The twin microcontroller families ESP8266 and ESP32 burst onto the scene and immediately became the budget-friendly microcontroller option for projects of all types. We’ve seen the line expand recently with the ESP32-C3 (packing a hacker-friendly RISC-V core) and ESP32-S3 with oodles of IO and fresh new CPU peripherals. Now we have a first peek at the ESP32-C6; a brand new RISC-V based design with the hottest Wi-Fi standard on the block; Wi-Fi 6.

There’s not much to go on here besides the standard Espressif block diagram and a press release, so we’ll tease out what detail we can. From the diagram it looks like the standard set of interfaces will be on offer; they even go so far as to say “ESP32-C6 is similar to ESP32-C3” so we’ll refer you to [Jenny’s] excellent coverage of that part. In terms of other radios the ESP32-C6 continues Espressif’s trend of supporting Bluetooth 5.0. Of note is that this part includes both the coded and 2 Mbps Bluetooth PHYs, allowing for either dramatically longer range or a doubling of speed. Again, this isn’t the first ESP32 to support these features but we always appreciate when a manufacturer goes above and beyond the minimum spec.

Welcome to the ESP32-C6

The headline feature is, of course, Wi-Fi 6 (AKA 802.11ax). Unfortunately this is still exclusively a 2.4GHz part, so if you’re looking for 5GHz support (or 6GHz in Wi-Fi 6E) this isn’t the part for you. And while Wi-Fi 6 brings a bevy of features from significantly higher speed to better support for mesh networks, that isn’t the focus here either. Espressif have brought a set of IoT-centric features; two radio improvements with OFDMA and MU-MIMO, and the protocol feature Target Wake Time.

OFDMA and MU-MIMO are both different ways of allowing multiple connected device to communicate with an access point simultaneously. OFDMA allows devices to slice up and share channels more efficiency; allowing the AP more flexibility in allocating its constrained wireless resources. With OFDMA the access point can elect to give an entire channel to a single device, or slice it up to multiplex between more than once device simultaneously. MU-MIMO works similarly, but with entire antennas. Single User MIMO (SU-MIMO) allows an AP and connected device to communicate using a more than one antenna each. In contrast Multi User MIMO (MU-MIMO) allows APs and devices to share antenna arrays between multiple devices simultaneously, grouped directionally.

Finally there’s Target Wake Time, the simplest of the bunch. It works very similarly to the Bluetooth Low Energy (4.X and 5.X) concept of a connection interval, allowing devices to negotiate when they’re next going to communicate. This allows devices more focused on power than throughput to negotiate long intervals between which they can shut down their wireless radios (or more of the processor) to extended battery life.

These wireless features are useful on their own, but there is another potential benefit. Some fancy new wireless modes are only available on a network if every connected device supports them. A Wi-Fi 6 network with 10 Wi-Fi 6 devices and one W-Fi 5 (802.11ac) one may not be able to use all the bells and whistles, degrading the entire network to the lowest common denominator. The recent multiplication of low cost IoT devices has meant a corresponding proliferation of bargain-basement wireless radios (often Espressif parts!). Including new Wi-Fi 6 exclusive features in what’s sure to be an accessible part is a good start to alleviating problems with our already strained home networks.

When will we start seeing the ESP32-C6 in the wild? We’re still waiting to hear but we’ll let you know as soon as we can get our hands on some development hardware to try out.

Thanks to friend of the Hackaday [Fred Temperton] for spotting this while it was fresh!

You Otter Be Able To Stream That Audio: Open Hardware Eclipses Chromecast Audio

When Google halted production of the Chromecast Audio at the start of 2019, there was a (now silent) outcry. Fans of the device loved the single purpose audio streaming dongle that delivered wide compatibility and drop-dead simplicity at a rock bottom $35 price. For evidence of this, look no further than your favorite auction site where they now sell for significantly more than they did new, if you can even find an active listing. What’s a prolific hacker to do about this clear case of corporate malice? Why, reinvent it of course! And thus the Otter Cast Audio V2 was born, another high quality otter themed hack from one of our favorite teams of hardware magicians [Niklas Fauth, Jan Henrik, Toble Miner, and Manawyrm].

USB-C and Ethernet, oh my!

The Otter Cast Audio is a disc about the shape and size of standard Chromecast (about 50mm in diameter) and delivers a nearly complete superset of the original Chromecast Audio’s features plus the addition of a line in port to redirect audio from existing devices. Protocol support is more flexible than the original, with AirPlay, a web interface, Spotify Connect, Snapcast, and even a PulseAudio sink to get your Linux flavored audio bits flowing. Ironically the one thing the Otter Cast Audio doesn’t do is act as a target to Cast to. [Jan] notes that out of all the protocols supported here, actual Cast support was locked down enough that it was difficult to provide support for. We’re keeping our fingers crossed a solution can be found there to bring the Otter Cast Audio to complete feature parity with the original Chromecast Audio.

But this is Hackaday, so just as important as what the Otter Cast Audio does is how it does it. The OtterCast team have skipped right over shoehorning all this magic into a microcontroller and stepped right up to an Allwinner S3 SOC, a capable little Cortex A7 based machine with 128 MB of onboard DDR3 RAM. Pint sized by the bloated standards of a fully interactive desktop, but an absolutely perfect match to juggling WiFi, Bluetooth, Ethernet, and convenient support for all the protocols above. If you’re familiar with these hackers’ other work it won’t surprise you that what they produced here lives up to the typical extremely high quality bar set by such wonders as this USB-C adapter for JBC soldering iron handles and this TS-100 mainboard replacement.

It sounds like a small production run might be on order in the future, but until then production files optimized for a particularly popular Chinese manufacturer are provided, with complete BOM and placement files. It sounds like turnkey production costs from that manufacturer are a shockingly reasonable $10 (total) per unit with most components, and come to a still-reasonable $22 with the remaining self-sourced components manually installed.

For a demo of the finished goods, check out the tweet embedded after the break.

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Sounding The Humble LED

Here at Hackaday we’re no strangers to the colorful glow of LEDs. But what if there was more to appreciate beneath the surface? Back in 2011 [Windell] over at Evil Mad Scientist dug into a certain variety of LED and discovered they had a song to sing.

Over the last couple decades, you’ve likely encountered the flickering “candle flame” variety of LED. Often found embedded in small plastic candle simulacra they are shaped like typical through hole “gumdrop” style LEDs, but pack some extra magic which causes them to flicker erratically. Coupled with a warm white color temperature the effect isn’t entirely dissimilar to the flickering of a candle flame.

To the Hackaday reader (and [Windell]) the cause of the flickering may be fairly clear, there is an IC embedded in the lens of the LED. See photo at top for an example of how this might look, helpfully magnified by the lens of the LED itself. Looking through the lens the captive die is visible, as well as the bond wires connecting it to the legs and light emitting diode itself. [Windell]’s observation is that together this assembly makes for a somewhat strange electrical component; from the perspective of the circuit it appears to randomly vary the current flowing through the LED.

He includes two interesting demos. One is that by attaching the flickering LED to a BJT he can turn it into a current amplifier and successfully drive a much more powerful 1W LED with the same effect. The other is that  with the power of the amplifier the same flickering LED can drive a buzzer as well. The effect is surprisingly pleasant, though we’d hesitate to call it musical.

For a more recent example of a similar phenomenon with a very different sound, check out out [Emily Velasco]’s playback of a similarly constructed RGB color changing LED, embedded below. We’ve seen optical tools used to decode LED flickers into data streams, but not for audio playback! We have also covered some LED flicker reverse engineering that spills more of the mystery sealed up in these specialized diodes.

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