We’re Dreaming Of A Circuit Sculpture Christmas

December 21, 2018 by Tom Nardi 6 Comments

Whether or not you chose to believe our claim that we planned it this way, the holidays happen to fall right smack in the middle of our ongoing Circuit Sculpture Contest, which challenges hackers to build circuits that double as bona fide works of art. It’s become almost too easy to spin up your own PCB, so why not try your hand at building in three dimensions and without a net? The holidays are a perfect time for it as it’s not only a reprieve from the work, school, or forced labor camp that usually ties up our waking hours, but can also be a source of inspiration.

Case in point, this festive LED Christmas tree entry that comes our way courtesy of [Vincent Mkes]. This one really has it all: a recognizable theme, fantastic wire work, copious amounts of LEDs, and in a touch that is sure to delight even the electronics Scrooges amongst our readership, he does it all with the venerable 555 timer. It’s really what the Circuit Sculpture Contest is all about: taking a circuit that might otherwise be pretty ordinary and turning it into something truly unique.

The astute Hackaday reader (as if there was any other type) will likely notice there are actually two NE555 timers under the tree, each blinking their respective bank of LEDs at a different frequency. This makes the final result a bit more vibrant, and through some last-minute revisions, [Vincent] was able to hook them both up to a single power supply to really capture the minimalist spirit of the Contest.

As an early Christmas gift to us all, [Vincent] has done an excellent job documenting this build so anyone who wishes to infuse their end of year party with a little diode-driven holiday cheer can follow along. He’s included build instructions as well as diagrams of the circuit, though we encourage anyone looking to make one of their own to experiment a bit and put their own spin on it. After all, this is supposed to be art.

There’s still plenty of time to get your own entry into the Circuit Sculpture Contest, Yule-related or otherwise. Just document your build on Hackaday.io and submit it before the January 8th, 2019 deadline. Remember that entries can’t just look cool, they still need to be functional. Words to live by in general, but doubly important when they’re the rules of a contest.

Lighting Up The Night Sky With A Flying POV Display

December 19, 2018 by Dan Maloney 14 Comments

We’ve seen loads of persistence of vision displays before, but this sky-writing POV display seems as though it may be a first. And we have to agree with its creators that it’s pretty cool.

The idea man on this was [Ivan Miranda], who conceived of a flying POV as a twist on his robotic dot-matrix beach printer. But without any experience in RC flight, he turned to fellow YouTuber [Tom Stanton], whose recent aerial builds include this air-powered plane, for a collaboration. [Ivan]’s original concept was a long strip of Neopixels that would be attached to the underside of a wide-wingspread plane. WIthout much regard for the payload limits of most RC planes, he came up with a working display that was 3 meters long. His video below shows it in use in his shop, with some pretty impressive long exposure images.

[Tom]’s part was to make the POV display flyable. He cut the length down to 2 meters and trimmed the weight enough to mount it to a quadcopter. Ungainly as the machine was, he was able to master its control enough to start painting pictures across the twilight sky. The images at the end of his video are actually stunning – we’re especially fond of Thunderbird 2, which takes us back to our childhood.

We’re not sure what the practical uses of this are, but that’s hardly the point. It’s enough that it’s an interesting project from an unlikely duo. Continue reading “Lighting Up The Night Sky With A Flying POV Display” →

Glowing Eyes For Regular Guys

December 18, 2018 by Lewin Day 47 Comments

Cosplayers continually push the boundary of what’s possible in live costuming, often taking effects from the silver screen and creating them in real life. [KyleofAsgard] is no exception, bringing Thor’s glowing eyes to life in this impressive build.

The helmet is a 3D printed piece from Thingiverse, painted and distressed by hand.

The build relies on special contact lenses, which [Kyle] suggests are best sourced by searching for “electric blue contact lenses”. These glow in the presence of UV light, which here is provided by a strip of UV LEDs embedded into Thor’s helmet from the recent Marvel movies.

The concept is simple, but the attention to detail is what makes this project a winner. Not content with an earlier build that was a tangle of wires and uncomfortable to use, [KyleofAsgard] made some smart upgrades. The battery for the LEDs and all circuitry is built into the helmet, making it easy to take on and off on those long convention days. For a more impressive effect, a relay is used to turn the LEDs on by remote control with a 433MHz module. This allows [Kyle] or an assistant to trigger the effect covertly, adding plenty of drama when the eyes suddenly begin to shine. It’s all done with off-the-shelf parts that even a novice could put together.

Giving credit where it’s due, [Kyle] notes that his work was inspired by that of Instagram cosplayer [missxboof], who executed a similar concept earlier this year. It’s great to see the cosplay community coming together and sharing tips and techniques online. Of course, if your tastes are more Metroid than Marvel, you might prefer this arm cannon build. Video after the break.

[Thanks to NZSmartie for the tip!]

Continue reading “Glowing Eyes For Regular Guys” →

Let’s Look At Some Cool Old LEDs

December 14, 2018 by Lewin Day 17 Comments

LEDs are now a mature technology, with all manner of colors and flavors available. However, back in the 1970s, it was early days for this fledgling display tech, and things looked very different. [IMSAI Guy] happened to work at the optoelectronics division of Hewlett-Packard during their development of LED displays, and has a handful of prototypes from those heady days.

The video is a great look at not only vintage display hardware, but also rarely seen prototypes that seldom left the HP offices. Matrix, 7-segment and even 16-segment devices are all in attendance here. There’s great macro photography of the packages, including the now-forgotten bubble displays as well as hermetically sealed glass packages. The parts all have a uniquely 1970s look, drenched in gold plating and otherwise just looking very expensive.

The followup video breaks out the microscope and powers up the displays. [IMSAI Guy] shares some useful tips on how to best tinker with unknown LED parts, as well as knowledge about the chemical compounds and manufacturing processes involved in LED production. If you don’t know your III-V compounds from your II-VI compounds, prepare to learn.

It’s always interesting to take a look back, and even better to get a peek at the experiments of engineers of the past.

If you’re wondering about applications of this hardware, we’ve seen messageboards and watches before. Video after the break.

Continue reading “Let’s Look At Some Cool Old LEDs” →

Christmas POV Display Makes Viewer Do The Work

December 9, 2018 by Tom Nardi 12 Comments

Hackaday readers have certainly seen more than a few persistence of vision (POV) displays at this point, which usually take the form of a spinning LED array which needs to run up to a certain speed before the message becomes visible. The idea is that the LEDs rapidly blink out a part of the overall image, and when they get spinning fast enough your brain stitches the image together into something legible. It’s a fairly simple effect to pull off, but can look pretty neat if well executed.

But [Andy Doswell] has recently taken an interesting alternate approach to this common technique. Rather than an array of LEDs that spin or rock back and forth in front of the viewer, his version of the display doesn’t move at all. Instead it has the viewer do the work, truly making it the “Chad” of POV displays. As the viewer moves in front of the array, either on foot or in a vehicle, they’ll receive the appropriate Yuletide greeting.

In a blog post, [Andy] gives some high level details on the build. Made up of an Arduino, eight LEDs, and the appropriate current limiting resistors on a scrap piece of perfboard; the display is stuck on his window frame so anyone passing by the house can see it.

On the software side, the code is really an exercise in minimalism. The majority of the file is the static values for the LED states stored in an array, and the code simply loops through the array using PORTD to set the states of all eight digital pins at once. The simplicity of the code is another advantage of having the ~~meatbag~~ human viewer figure out the appropriate movement speed on their own.

This isn’t the only POV display we’ve seen with an interesting “hook” recently, proving there’s still room for innovation with the technology. A POV display that fits into a pen is certainly a solid piece of engineering, and there’s little debate the Dr Strange-style spellcaster is one of the coolest things anyone has ever seen. And don’t forget Dog-POV which estimates speed of travel by persisting different images.

[Thanks to Ian for the tip.]

An Over-engineered LED Sign Board

December 8, 2018 by Inderpreet Singh 10 Comments

Never underestimate the ability of makers in over thinking and over-engineering the simplest of problems and demonstrating human ingenuity. The RGB LED sign made by [Hans and team] over at the [Hackheim hackerspace] in Trondheim is a testament to this fact.

As you would expect, the WS2812 RGB LEDs illuminate the sign. In this particular construction, an individual strip is responsible for each character. Powered by an ESP32 running FreeRTOS, the sign communicates using MQTT and each letter gets a copy of the 6 x 20 framebuffer which represents the color pattern that is expected to be displayed. A task on the ESP32 calculates the color value to be displayed by each LED.

The real question is, how to calibrate the distributed strings of LEDs such that LEDs on adjacent letters of the sign display an extrapolated value? The answer is to use OpenCV to create a map of the LEDs from their two-dimensional layout to a lookup table. The Python script sends a command to illuminate a single LED and the captured image with OpenCV records the position of the signal. This is repeated for all LEDs to generate a map that is used in the ESP32 firmware. How cool is that?

And if you are wondering about the code, it is up on [Github], and we would love to see someone take this up a level. The calibration code, as well as the Remote Client and ESP32 codes, are all there for your hacking pleasure.

Its been a while since we have seen OpenCV in action like with the Motion Tracking Turret and Face Recognition. The possibilities seem endless. Continue reading “An Over-engineered LED Sign Board” →

Negative Voltage Pushes AVR To New Heights

December 8, 2018 by Tom Nardi 38 Comments

If we say that a hacker is somebody who looks at a “solved” problem and can still come up with multiple alternative solutions, then [Charles Ouweland] absolutely meets the grade. Not that we needed more evidence of his hacker cred given what we’ve seen from him before, but he recently wrote in to tell us about an interesting bit of problem solving which we think is a perfect example of the principle. He wanted to drive a salvaged seven segment LED display with an AVR microcontroller, but there was only one problem: the display needs 15V but the AVR is only capable of 5V. So what to do?

As it turns out, the first step to solving the problem was verifying there was actually a problem to begin with. [Charles] did some experimentation and found that the display didn’t actually need 15V to operate, and in fact would light up well enough at just 6.5V. This lowered the bar quite a bit, but it was still too high to power directly from the chip.

There were a few common ways to solve this problem, which no doubt the Hackaday reader is well aware of. But [Charles] wanted to take the path less traveled. More specifically, the path with the least amount of additional components he had to put on his PCB. He set out to find the absolute easiest way to make his 5V AVR light up a 6.5V LED, and ended up coming with a very clever solution that some may not even know is possible.

He reasoned that if he connected the source pins of two BS170 MOSFETs to a voltage of -1.5V, even when the AVR pin was 0V, they would be still be receiving 1.5V. This virtual “step ladder” meant that once the AVR’s pin goes high (5V), the relative voltage would actually be 6.5V and enough to drive his LEDs. Of course the only problem with that is that you need to have a source for -1.5V.

Getting a negative voltage would normally require adding more components to the design (which he set out to avoid in the first place), but then he came up with another clever idea. To pull the trick off, he actually feeds the AVR 6.5V, but raises the ground voltage by 1.5V with the addition of two 1N4007 diodes. This way the AVR gets a voltage within its capabilities and still can provide a relative 6.5V to the LEDs.

One might say [Charles] took the Kobayashi Maru approach, and simply redefined the rules of the game. But such is the power of the confounding negative voltage.