Playing The Pixelflut

August 1, 2020 by Kerry Scharfglass 7 Comments

Every hacker gathering needs as many pixels as its hackers can get their hands on. Get a group together and you’ll be blinded by the amount of light on display. (We propose “a blinkenlights” as the taxonomic name for such a group.) At a large gathering, what better way to show of your elite hacking ability than a “competition” over who can paint an LED canvas the best? Enter Pixelflut, the multiplayer drawing canvas.

Pixelflut has been around since at least 2012, but it came to this author’s attention after editor [Jenny List] noted it in her review of SHA 2017. What was that beguiling display behind the central bar? It turns out it was a display driven by a server running Pixelflut. A Pixelflut server exposes a display which can be drawn on by sending commands over the network in an extremely simple protocol. There are just four ASCII commands supported by every server — essentially get pixel, set pixel, screen size, and help — so implementing either a client or server is a snap, and that’s sort of the point.

While the original implementations appear to be written by [defnull] at the link at the top, in some sense Pixelflut is more of a common protocol than an implementation. In a sense, one “plays” one of a variety of Pixelflut minigames. When there is a display in a shared space the game is who can control the most area by drawing the fastest, either by being clever or by consuming as much bandwidth as possible.

Then there is the game of who can write the fastest more battle-hardened server possible in order to handle all that traffic without collapsing. To give a sense of scale, one installation at 36c3 reported that a truly gargantuan 0.5 petabytes of data were spent at a peak of rate of more than 30 gigabits/second, just painting pixels! That’s bound to bog down all but the most lithe server implementation. (“Flut” is “flood” in German.)

While hacker camps may be on pause for the foreseeable future, writing a performant Pixelflut client or server seems like an excellent way to sharpen one’s skills while we wait for their return. For a video example check out the embed after the break. Have a favorite implementation? Tell us about it in the comments!

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Tiny Circuit Sculpture Keeps The Night Watch

July 27, 2020 by Kristina Panos 8 Comments

If you’re planning to get into circuit sculpture one of these days, it would probably be best to start with something small and simple, instead of trying to make a crazy light-up spaceship or something with a lot of curves on the first go. A small form factor doesn’t necessarily mean it can’t also be useful. Why not start by making a small automatic night light?

The circuit itself is quite simple, especially because it uses an Arduino. You could accomplish the same thing with a 555, but that’s going to complicate the circuit sculpture part of things a bit. As long as the ambient light level coming in from the light-dependent resistor is low enough, then the two LEDs will be lit.

We love the frosted acrylic panels that [akshar1101] connected together with what looks like right angle header pins. If you wanted to expose the electronics, localize the light diffusion with a little acrylic cover that slips over the LEDs. Check it out in the demo after the break.

There’s more than one way to build a glowing cuboid night light. The Rubik’s way, for instance.

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500 Lasers Are Not Necessarily Better Than One, But They Look Great

July 13, 2020 by Dan Maloney 29 Comments

If playing with but a single laser pointer is fun, then playing with 500 laser pointers must be 500 times the fun, right? So by extension, training 500 laser pointers on a single point must be the pinnacle of pointless mirth. And indeed it is.

When we first spotted this project, we thought for sure it was yet another case of lockdown-induced boredom producing an over-the-top build. Mind you, we have no problem with that, but in this case, [nanoslavic] relates that this is actually a project from a few years back. It’s really as simple as it looks: 500 laser pointer modules arranged on a plate with a grid of holes in a 25 by 20 array. As he placed the laser modules on the board with a glob of hot glue, he carefully aimed each one to hit a single point about a meter and a half away. There are also a handful of blue LEDs nestled into the array, because what project is complete without blue LEDs?

The modules are wired in concentric circuits and controlled by a simple bank of toggle switches. Alas, 500 converging ~~150-mW~~ 5 mW lasers do not a ~~75-W~~ 2.5 W laser make; when fully powered, the effect at the focal point is reported to be only a bit warm. But it looks incredible, especially through smoke. Throwing mirrors and lenses into the beam results in some interesting patterns, too.

You’ll still need to take safety seriously if you build something like this, of course, but this one is really just for show. If you’re really serious about doing some damage with lasers, check out the long list of inadvisable laser builds that [Styropyro] has accumulated — from a high-powered “lightsaber” to a 200-Watt laser bazooka.

(Terminate your beams carefully, folks. We don’t want anyone going blind.)

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Live Map Of London Tube Created In PCB And Lights

July 5, 2020 by Bryan Cockfield 20 Comments

If you’re a frequent traveler on a public transit system, it can be helpful to know when the trains or buses are arriving and if there are any delays. We might reach for a tablet to mount on the wall, but that relies on keeping the OS, the software, and its library dependancies up to date. For true reliability you’ll need to build directly in hardware, which is exactly what this map of the London tube system uses.

The base map is printed directly on PCB, with LEDs along each of the major routes to indicate the current location of the trains. A few small chips handle the WiFi connection — it appears to our eye to be an ESP8266 — and pulling the information about the trains from the London Underground API (it would be virtually impossible to build everything for this project in hardware). The hardware can be easily reprogrammed, and with the PCB layout this could be adapted for other public transit fairly easily.

Even apart from the philosophical differences on design between hardware and software approaches, we still appreciate the aesthetic of LEDs on PCB. In fact, we’ve seen a whole host of artwork on PCBs ever since the price came down dramatically in the past two decades.

Thanks to [Al] for the tip!

LED Art Hack Chat

June 29, 2020 by Dan Maloney 1 Comment

Join us on Wednesday, July 1 at noon Pacific for the LED Art Hack Chat with Aaron Oppenheimer!

From the first time humans crawled into a cave with a bit of charcoal to sketch scenes from the world around them, artists have been searching for new media and new ways to express themselves. Natural products ruled for thousands of years, with pigments stolen or crafted from nature as well as wood, ivory, bone, and stone for carving. Time and experience guided our ancestors to new and better formulations and different materials, to the point that what qualifies as art and what we’d normally think of as technology have, in many cases, blended into one, with the artist often engineering projects of mammoth proportions and breathtaking beauty.

Aaron Oppenheimer co-founded color+light, a company that specializes in large-scale custom art installations for companies like Google, Nike, and Nissan. One of their projects, the “Oddwood Tree”, is displayed alongside other gigantic art pieces at Area15 on the Las Vegas strip. His most recent project, fluora, is a digital houseplant, with addressable LEDs in the leaves that can be controlled by a smartphone app or respond to stimuli in the environment.

Aaron will join us on the Hack Chat to discuss the LED as artistic medium. Join us as we learn what it takes to make enormous art that’s strong enough to interact with yet responsive enough to be engaging.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, July 1 at 12:00 PM Pacific time. If time zones have you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Chaotic Oscillator From Antique Logic

June 23, 2020 by Bryan Cockfield 35 Comments

While working on recreating an “ancient” (read: 60-year-old) logic circuit type known as resistor-transistor logic, [Tim] stumbled across a circuit with an unexpected oscillation. The oscillation appeared to be random and had a wide range of frequency values. Not one to miss out on a serendipitous moment, he realized that the circuit he built could be used as a chaotic oscillator.

Chaotic systems can be used for, among other things, random number generation, so making sure that they do not repeat in a reliable way is a valuable property of a circuit. [Tim]’s design uses LEDs in series with the base of each of three transistors, with the output of each transistor feeding into the input of the next transistor in line, forming a ring. At certain voltages close to the switching voltages of the transistors, the behavior of the circuit changes unpredictably both in magnitude and frequency.

Building real-life systems that exhibit true randomness or chaotic behavior are surprisingly rare, and even things which seem random are often not random enough for certain applications. [Tim]’s design benefits from being relatively simple and inexpensive for how chaotic it behaves, and if you want to see his detailed analysis of the circuit be sure to visit his project’s page.

If you want to get your chaos the old fashioned way, with a Chua circuit, look out for counterfeit multipliers.

Hacking A Cheap Disco Light For UV Effects

June 15, 2020 by Lewin Day 21 Comments

Back in the early days of disco, filament bulbs were all the rage. Whether tungsten, halogen, or other obscure types, party lighting involved lots of watts and lots of heat. These days, the efficiency of LEDs makes everything a lot cheaper, lighter, and lower power. [Big Clive] decided to dive into a cheap moonflower-type disco light from China, replacing the insides along the way.

The final effect particularly shines when used on fluorescent materials.

The light originally consisted of an 8×8 grid of LEDs, driven by shift registers for a simple chase effect. Surprisingly, the power supply and other hardware inside seemed to at least make an attempt to meet UK regulations. However, [Big Clive] had other plans, whipping up a replacement PCB packing 64 UV LEDs. The video is informative, showing how with a few simple passive components, it’s easy to drive these LEDs from mains without excessive circuitry required to step down to more usual DC voltages.

The final result is a neat UV grid light that would look excellent through some fog on the dance floor. We’ve seen [Big Clive]’s teardowns before, too – like this nefarious CAN bus interceptor found in a Mercedes. Video after the break.

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