Pi replaces Keiko-chan

[Tobias Kuhn] and a handful of colleagues at his workplace built Crystal Signal Pi, a Raspberry Pi based low-cost alternative for a notification device that provides visual, audio and network warnings about server problems. [Tobias] works for a Japanese company where it is critical for their servers to keep humming nicely all the time. Any emergencies or error conditions must be broadcast immediately so the technicians can fix it ASAP. Network enabled warning light stalks are used to provide these alerts. A local company produces a series of indicator and hazard warning lights which are colloquially called as Keiko-chan. These are similar to the hazard warning tower lights commonly fixed on machines on factory floors or many kinds of vehicles such as fork lifts. The Kieko-chans add a few bells and whistles making them more suitable for use in the server data centre — a Gigabit LAN port for wired networks and a USB port for WiFi modules. So, besides visual and audio warnings, it can also transmit messages over the network to alert the maintenance folks. Using this commercial solution should not have been a problem were it not for their rather hefty price tag of almost $500 per pop.

So [Tobias] decided to build his own warning lights based around the Raspberry Pi. After two rounds of prototypes, a simple HAT was designed that could be plugged in to a Pi. Details of the hardware are sketchy, but it’s simple enough to figure out. The part list consists of a PLCC-6 style RGB LED, three transistors to drive the three LED pins, a voltage regulator with a couple of electrolytic capacitors and a large push button. A simple acrylic case, and an acrylic cylinder mounted on top of the RGB LED creates a nice edge lit effect for the indicator.

The code for the Crystal Pi is hosted on Github, and includes handy scripts to make installation easy. Once installed, the Crystal Pi can be accessed and controlled either through a web-based GUI or via the API. There are some more interesting features already implemented or scheduled for later, so do check out the blog and the repository for more. Check out the video below to see the Crystal Pi in action.

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Neural Network Really Ties The Room Together

If there’s one thing that Hollywood knows about hackers, it’s that they absolutely love data visualizations. Sometimes it’s projected on a big wall (Hackers, WarGames), other times it’s gibberish until the plot says otherwise (Sneakers, The Matrix). But no matter what, it has to look cool. No hacker worth his or her salt can possibly work unless they’ve got an evolving Venn diagram or spectral waterfall running somewhere in the background.

Inspired by Hollywood portrayals, specifically one featured in Avengers: Age of Ultron, [Zack Akil] decided it was time to secure his place in the pantheon of hacker wall visualizations. But not content to just show meaningless nonsense on his wall, he set out to create something that was at least showing actual data.

[Zack] created a neural network to work through multi-label classification data in Python using the scikit-learn machine learning suite. The code takes the values from the neutral network training algorithm and converts them to RGB colors by way of an Arduino. Each “node” in the neutral network is 3D printed in translucent filament, and fitted with an RGB LED module. These modules are then connected to each other via side-glow fiber optic tubes, so that the colors within the tubes are mixed depending on the colors of the nodes they are attached to. This allows for a very organic “growing” effect, as colors move through the network node-by-node.

In the end this particular visualization doesn’t really mean anything; the data it’s working on only exists for the purposes of the visualization itself. But [Zack] succeeded in creating a practical visualization of machine learning, and if you’re the kind of person who needs to keep tabs on learning algorithms, some variation of this design may be just what you’re looking for.

If AI isn’t your thing but you still want a wall of RGB LEDs, maybe you can use this phased array antenna visualizer instead. If you’re really hip, maybe you’ll go the analog route and put a big gauge on the wall.

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LED Princess Dress Also Lights Up Girl’s Face

We’re pretty sure that [Luke] took Uncle of the Year last Halloween when he made an RGB LED princess dress for his niece. He recently found the time to document the build with a comprehensive how-to that’s just in time for Halloween ’17.

[Luke] made the system modular so that his niece could use it with any dress. The RGB LED strips are actually fastened down the inside of a petticoat — a fluffy, puffy kind of slip that’s worn underneath the dress. The LEDs face in toward the body, which helps diffuse the light. [Luke] first attached the strips with their own adhesive and then spent a lot of time sewing them down so they stayed put. At some point, he found that hot glue worked just as well.

The coolest part of this project (aside from the blinkenlights of course) is the power source. [Luke] used what he already had lying around: an 18V Ryobi battery pack. He wired a step-converter to it using a printed cap from Shapeways that’s designed to connect metal clips to the battery contacts. This cap really makes these packs useful for a lot of projects that need long-lasting portability.

These batteries are rated for 240W, which is overkill considering the load. But there’s a reason: it keeps heat to a minimum, since the electronics are hidden inside a cute little backpack. Speaking of cute, you can see his niece model the dress after the break.

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Sense Hat Comes Alive

Remember the Raspberry Pi Sense Hat? Originally designed for a mission to the International Space Station, the board has quite a few sensors onboard as well as an 8×8 RGB LED matrix. What can you do with an 8×8 screen? You might be surprised if you use [Ethan’s] Python Sense Hat animation library. You can get the full visual effect in the video below.

The code uses an array to represent the screen, which isn’t a big deal since there are only 64 elements. Turning on a particular element to animate, say, a pong puck, isn’t hard with or without the library. Here’s some code to do it with the library:

for x in range(0,7):
 ect.cell(image,[0,x],[randint(0,255), randint(0,255), randint(0,255)],0.1)
 ect.cell(image,[0,x],e,0.1)
for x in range(7,0, -1):
 ect.cell(image,[0,x],[randint(0,255), randint(0,255), randint(0,255)],0.1)
 ect.cell(image,[0,x],e,0.1)

Each loop draws a box with a random color and then erases it before going to the next position. The second for loop makes the puck move in the opposite direction. You can probably deduce that the first argument is the screen array, the second is the position. The third argument sets the color, and the final argument sets an animation timer. Looking at the code, though, it does look like the timer blocks which is probably not going to work for some applications.

If that’s all there was, this wouldn’t be worth too much, but you can also draw triangles, circles, and squares. For example:

ect.circle(image,(4,4), 3, [randint(0,255), randint(0,255), randint(0,255)], 0.1)

We covered the Sense Hat awhile back. Of course, it does a lot more than just light up LEDs as you can see from this weather dashboard.

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Ask Hackaday: What About the Diffusers?

Blinky LED projects: we just can’t get enough of them. But anyone who’s stared a WS2812 straight in the face knows that the secret sauce that takes a good LED project and makes it great is the diffuser. Without a diffuser, colors don’t blend and LEDs are just tiny, blinding points of light. The ideal diffuser scrambles the photons around and spreads them out between LED and your eye, so that you can’t tell exactly where they originated.

We’re going to try to pay the diffuser its due, and hopefully you’ll get some inspiration for your next project from scrolling through what we found. But this is an “Ask Hacakday”, so here’s the question up front: what awesome LED diffusion tricks are we missing, what’s your favorite, and why?

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Beautiful Linear RGB Clock

Yup, another clock project. But here, [Jan] builds something that would be more at home in a modern art museum than in the dark recesses of a hacker cave. It’s not hard to read the time at all, it’s accurate, and it’s beautiful. It’s a linear RGB LED wall clock.

7512951486134540347You won’t have to learn the resistor color codes or bizarre binary encodings to tell what time it is. There are no glitzy graphics here, or modified classic timepieces. This project is minimal, clean, and elegant. Twelve LEDs display the hours, six and nine LEDs take care of the minutes in add-em-up-coded decimal. (It’s 3:12 in the banner image.)

The technical details are straightforward: WS2812 LEDs, an Arduino, three buttons, and a RTC. You could figure that out by yourself. But go look through the log about building the nice diffusing plexi and a very clean wall-mounting solution. It’s the details that separate this build from what’s hanging on our office wall. Nice job, [Jan].

Cheap LCD TV gets cheaper fix

Most hacks need some fair bit of skill and knowledge if you want to come out successful at the other end. Others, you just plunge in blindly with a “heck, it’s already broken so I can’t make it any worse” attitude. Throwing caution to the wind, you dive in, rip things up, and see if you can manage to catch the bull by the horns.

[Jim]’s cheap LCD TV, barely a few years old, died. It was purchased from the store whose blue polo-shirted cashiers can drive you nuts with their incessant questions. [Jim] just rolled up his sleeves and rather haphazardly managed to fix his TV while adding an extra feature along the way.

His initial check confirmed that the LCD panel worked. Using a flashlight, he could see that the panel was displaying video which meant it was the backlight that wasn’t working. Opening up the TV, he located the LED driver board whose output turned out to be zero volts. [Jim] happened to have a lot of WS2812B strips lying around, along with their power supplies and RGB color controllers. The obvious solution was to ditch the existing LEDs and power supply and use the WS2812B strips.

Surprisingly, the original backlight consisted of just 21 LEDs arranged in three rows. He ripped those out, put in the WS2812B strips, and taped the jumble of wires out of sight. After putting it back together, [Jim] was happy to see it worked, although the new strips were not as bright as the old ones, causing some uneven light bands. He solved this by adding a few more strips of LEDs. It took him a couple of hours to fix his TV, but by the end of it, he had a TV whose backlight could be adjusted to any color using the external color controllers — although we’re not too sure what good that would be.