Animated LED Arrows Point The Way

September 24, 2022 by Jonathan Bennett 11 Comments

Visitors at the Garden D’Lights in Bellevue, Washington had a problem. While touring the holiday lights show, they kept straying off the path. The event organizers tried some simple LED arrows, but they were just more points of light among a sea filled with them. This is when [Eric Gunnerson] was asked to help out. He’s apparently had some experience with LED animations, even cooking up a simple descriptor language for writing animations driven by an ESP32. To make the intended path obvious, he turned to a PVC board with 50 embedded WS2812 pixels –RGB controllable LEDs. The control box was a USB power adapter and an ESP8266, very carefully waterproofed and connected to the string of pixels. The backer board is painted black, to complete the hardware. Stick around after the inevitable break, to get a look at the final

The description of the build process is detailed and contains some great tips, but without a clever LED animation, it’s still of questionable utility. The pattern chosen is great, with the LEDs being blue most of the time, and a flame-like gradient chasing through the arrow every couple seconds. It’s obviously different from the lights of the show, and seems to be a real winner. [Eric] has published his code, with the sheepish caveat that he had to reinvent the wheel once again, and couldn’t reuse any of his previous LED animation work on this one. It’s a simple hack, but a great build log, and an effective solution to a subtle problem. And if addressable LEDs are your thing, check out our other hacks!

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Chandelier Mimics The Solar Analemma

September 24, 2022 by Lewin Day 14 Comments

The solar analemma is the shape the sun traces out when photographed each day at the same time and same location for a whole year – but you probably knew that already. [makendo] decided to use this skewed figure-eight shape as the inspiration for a chandelier, and the results are stunning.

A laser cutter was used to cut out segments of the analemma shape in plywood, such that they could slot together into the full form. These were then glued together on to a plywood sheet as a template to cut out the full-size form in a single piece. Some laminate edging was then added and the entire thing was given a coat of black gloss paint. String lights were cut up to provide the many globe fittings required, and installed on the back of the chandelier.

[makendo] notes that with a full 51 bulbs in the chandelier, it’s way too bright for most dining room settings. A dimmer is thus used to tone down the output to reduce eyestrain at mealtimes. It’s a fun build, and we’ve always loved light fixtures that are inspired by astronomy. If you like the moon more than the sun, though, there’s a build for you too!

As Europe Goes To LEDs, Scientists Worry

September 19, 2022 by Al Williams 271 Comments

There was a time when street lighting means someone had to go light the lamps. Electricity changed that, but street and outdoor lighting has been quietly going through a new revolution: LEDs. The problem, though, is that LEDs provide what scientists call “broad white” light and there are concerns about the impact the unnatural lighting will have on ecosystems, including people and animals.

Of course, the first step in worrying about something is to measure it. You would think that satellites would have a bird’s-eye view of the nighttime lighting landscape, and, of course, they do. But most of the imagery isn’t suitable for looking at the spectrum of wavelength data scientists need to quantify what they call ALAN — Artificial Light at Night.

The ISS imaging is, however, sufficient. Using special data techniques, they were able to track the adoption of LEDs over sodium lights and other technologies between 2012-2013 and 2014-2020 across Europe. For example, in the title image, you can see Belgium with an orange tint indicating low-pressure sodium lights. The Netherlands, France, and the UK have a more yellow hue, indicating high-pressure sodium lamps. Germany is more of a blue color due to fluorescent and mercury vapor bulbs.

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Digital Light Pipes Clock various view of seven-segment display using illuminated light-pipes

LED Clock Has Its Pipes On Display

September 19, 2022 by Dave Walker 4 Comments

For most hackers and makers, building a clock is a rite of passage. Few, though, will be as unusual and engaging as this design by [TerraG2].

By combining addressable LEDs, light pipes and 7-segment displays, [TerraG2] has built a timepiece that looks great and will surely be a great conversation starter as well. It’s packed full of features such as automatic brightness control, an accelerometer controlled user interface, and WiFi to make sure it’s always accurate.

partial rear view of the clock showing illuminated light pipes — Partial rear view of the clock showing illuminated light pipes

The decision to leave the light pipes visible behind the main display really makes the project stand out from other clock builds, and the methods [TerraG2] has used to achieve this look will no doubt be transferable to a host of other projects.

The LEDs are courtesy of a standard 8×8 RGB matrix, with a custom 3D-printed shroud to hold the light pipes in place and a clever connector at the other end to illuminate the segments. With two LEDs per segment, seven segments per digit, and four digits, there’s even room for some extra features down the line if you can think of a use for those eight spare LEDs.

The brain of the project is an ESP8266 D1 with an MPU6050 inertial measurement unit (IMU) to detect when it’s flipped over to change the color scheme.

Full documentation is on Github, and a video of the clock in use is after the break.

Light pipes have been used to great effect in some other clock projects we’ve seen, such as this modern Nixie clock and this “clock of clocks”, as well as in this light organ that we showed recently.

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Building A Glowing Demon Core Lamp

August 31, 2022 by Lewin Day 15 Comments

The so-called Demon Core was a cursed object, a 6.2 kilogram mass of plutonium intended to be installed in a nuclear weapon. Instead, slapdash experimental techniques saw it feature in several tragic nuclear accidents and cause multiple fatalities. Now, you can build yourself a lamp themed after this evil dense sphere.

A later recreation of the infamous “Slotin Accident” that occurred with the Demon Core. Credit: Public Domain, Los Alamos National Laboratory

Creator [skelly] has designed the lamp to replicate the Slotin incident, where the spherical Demon Core was placed inside two half-spheres of beryllium which acted as neutron reflectors to allow it to approach criticality. Thus, the core is printed as a small sphere which is thin enough to let light escape, mimicking the release of radiation that doomed Louis Slotin. The outer spheres are then printed in silvery PLA to replicate the beryllium half-spheres. It’s all assembled atop a stand mimicking those used in the Los Alamos National Laboratory in the 1940s.

To mimic the Core’s deadly blue glow, the build uses cheap LED modules sourced from Dollar Tree lights. With the addition of a current limiting resistor, they can easily be run off USB power in a safe manner.

The Demon Core has become a meme in recent times, perhaps as a new generation believes themselves smart enough not to tinker with 6.2 kilograms of plutonium and a screwdriver. That’s not to say there aren’t still dangerous nuclear experiments going on, even the DIY kind. Be careful out there!

Share Screen To RGB Panel With Pi Pico W

August 28, 2022 by Danie Conradie 13 Comments

RGB LEDs are great for adding a bit of color to your life, and it’s even more satisfying to use a matrix of them as a graphic display. [bitluni] built an RGB LED display with Pi Pico to which you can share a pixelated version of your PC’s screen.

[bitluni] wanted to gain some experience with MicroPython on the Raspbery Pi Pico W, and had previously used WebSockets to transmit display data over WiFi. Unfortunately, the available MicroPython WebSockets implementation didn’t leave enough RAM for the rest of the code. Instead, he set up a simple HTTP server on the Pico that receives the pixel data as a POST request. This makes for a slow refresh rate but still looks great, especially with the 3D printed rear-projection frame.

To send display data from the computer, [bitluni] uses a simple locally hosted HTML page that takes the Pico’s IP address, and prompts you to select the display or window you want to share. It uses JavaScript to grab the display data, generate the required low-res pixel values, and send the POST request.

This looks like a fun weekend project to add to your lab or home and only costs about $20 in parts. It’s basically a scaled-down version of his giant ping pong ball wall display.

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LED Clock Uses Micro QR Codes To Show The Time

August 28, 2022 by Robin Kearey 15 Comments

As you probably know, we love our clocks here at Hackaday. Odd display technologies are always interesting to see, as are unusual encoding techniques such as binary, ternary or higher-radix number systems. Still, clocks are typically meant to be human-readable, even if their encoding might be a little eccentric.

[Kitchi] however built an LED-based clock that is not human-readable, at least not without quite a bit of training. This is because it displays the time by generating a QR code, which only becomes readable to most humans through the use of a smartphone app. Of course, this negates the need for a clock since your smartphone will already have one anyway — but whoever said a clock needs to be useful?

To be fair, the display could conceivably be read by a determined human, since the QR format used is the tiny Micro QR M2 version that measures only 13×13 pixels. It’s capable of storing ten decimal digits, just enough to hold the date and time in mmddhhmmss format. The fixed part of the QR code is made of paper, while the variable part is formed through a grid of 90 white LEDs. The LEDs are mounted on a piece of prototype board along with a PIC 16F1504 microcontroller, two TM1637 LED drivers and a DS1307 real-time clock with battery backup.

If decoding QR codes is not your thing, or you simply haven’t got your smartphone on you, then the QR clock can also be set to a more human-readable format by adding a jumper. The time will then scroll across the LED screen in ordinary decimal format.

The video in the link is in Japanese, with no automatic translation available, but the build process is clearly shown and should be understandable even if you can’t follow the cheerful robotic narrator. We’ve seen a couple of QR-code based clocks before, some with an LCD screen and some with retro styling, but all of those use the larger standard QR code which definitely no human can decode visually. Or can you? Let us know in the comments!

Thanks for the tip, [J. Peterson]!