Mike Harrison Knows Everything About LEDs

November 25, 2019 by Jenny List 19 Comments

Driving an LED and making it flash is probably the first project that most people will have attempted when learning about microprocessor control of hardware. The Arduino and similar boards have an LED fitted, and turning it on and off is a simple introduction to code. So it’s fair to say that many of us will think we have a pretty good handle on driving an LED; connect it to a I/O pin via a resistor and that’s it. If this describes you, then Mike Harrison’s talk at the recent Hackaday Superconference (embedded below) will be an education.

Mike has appeared on these pages multiple times as he pushes LEDs and PCB techniques to their limits, even designing our 2017 Superconference badge, and his many years of work in the upper echelons of professional LED installations have given him an unrivaled expertise. He has built gigantic art projects for airports, museums, and cities. A talk billed as covering everything he’s learned about LEDs them promises to be a special one.

If there’s a surprise in the talk, it’s that he’s talking very little about LEDs themselves. Instead we’re treated to a fundamental primer in how to drive a lot of LEDs, how to do so efficiently, with good brightness and colour resolution, and without falling into design traps. It’s obvious that some of his advice such at that of relying on DIP switches rather than software for configuration of multi-part installations has been learned the hard way.

Multiple LEDs at once from your driver chip, using a higher voltage.

We are taken through a bit of the background to perceived intensity and gamma correction for the human eyesight. This segues neatly into the question of resolution, for brightness transitions to appear smooth it is necessary to have at least 12 bits, and to deliver that he reaches into his store of microcontroller and driver tips for how to generate PWM at the right bitrate. His favoured driver chip is the Texas TLC5971, so we’re treated to a primer on its operation. A useful tip is to use multiple smaller LEDs rather than a single big one in the quest for brightness, and he shows us how he drives series chains of LEDs from a higher voltage using just the TI chip.

Given the content of the talk this shouldn’t come as a shock, but at the end he reminds us that he doesn’t use all-in-one addressable LEDs such as the WS2932 or APA102. These are the staple of so many projects, but as he points out they are designed for toy type applications and lack the required reliability for a multi-thousand LED install.

Conference talks come in many forms and are always fascinating to hear, but it’s rare to see one that covers such a wide topic from a position of experience. He should write it into a book, we’d buy it!

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Keeping Time With Blinkenlights

November 24, 2019 by Tom Nardi 10 Comments

If we’ve learned anything over the years, it’s that hackers like weird clocks, and they love packing as many multicolored LEDs into a device as is humanly possible. Combine both of those concepts into one project, and you’ve got a perfect storm. So as far as unnecessarily complex timepieces go, we’d say the “Crazy Clock 4” built by [Fearless Night] ranks up there among the all-time greats.

This Arduino Pro Mini powered clock syncs the current time via GPS, with a temperature compensated DS3231 RTC to keep it on the straight and narrow between satellite downlinks. Once the clock has the correct time, how do you read it? Well, at the top you’ve got a basic numerical readout for the normies, and next to that there’s a circular LED display that looks like it could double as a sci-fi movie prop. On the lower level there’s a binary clock for the real show-offs, and as if that wasn’t enough, there’s even dual color-coded analog meters to show the hours and minutes.

[Fearless Night] has provided everything you need to follow along at home, from the Arduino source code to the 3D models of the case and Gerber files for the custom PCB. Personally we think just the top half of the clock would be more than sufficient for our timekeeping needs. If nothing else it should help save some energy, as the clock currently pulls an incredible 20 watts with all those LEDs firing off.

Should you decide to take a walk down memory lane and check out some of the other interesting LED clocks we’ve featured in the past, you’d be busy for quite awhile. But for our money, it’s still hard to beat the impossibly obtuse single-LED clock.

Mimic Artfully Employs LEDs In Fashion

November 24, 2019 by Lewin Day 6 Comments

Any science fiction piece set in the near-future involves clothes that light up or otherwise have some form of electronics inside. This hasn’t happened in mainstream fashion just yet, but [Amped Atelier] are doing serious work in the field. Mimic was their entry for the 2016 MakeFashion Gala, serving as a great example of LEDs in fashion done right.

Mimic consists of two pieces, designed as cocktail dresses that mimic their surroundings, in much the same way as a chameleon. LEDs are controlled by an Arduino, fitted with a colour sensor. When activated, the Arduino can change the color of the LEDs to match whatever is presented to the sender. This technology could serve as a great way to avoid clashing with a friend’s outfit, or to send a surreptitious signal to your ride that you’re ready to leave.

The LEDs are hidden beneath attractive geometric diffusers, which are 3D printed directly on to the fabric of the outfit. This gives an attractive, finished look to the garment, and allows the diffusers to naturally flow with the lines of the piece.

These pieces show that it’s possible to create glowable night wear that is as stylish as it is high tech. If you’re looking for something a little edgier however, we’ve got that too. Video after the break.

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Replica Marshmello Helmet Is A Tidy Halloween Build

November 22, 2019 by Lewin Day 2 Comments

As the saying goes – you don’t need a stylized, bedazzled helmet to have a successful career in EDM, but it helps. Marshmello is the latest in a long line of musicians to sport bespoke headgear, and [MikeTheSuperDad] undertook the construction of a replica for Halloween.

The build starts with a piece of concrete form tube as the base of the helmet. This is combined with 3D printed components to create a grid in which to place WS2812B LED strings. These are controlled by an Arduino Pro Mini, which is responsible for handling the animations. Further 3D printed parts are used as templates to cut out the characteristic eyes and mouth, as well as to cover the top. Plastic sheeting is then used over the top of everything to diffuse the LEDs and provide the final look, with black mesh behind the eyes and mouth making them properly stand out.

Marshmello should be lauded for creating a helmet with a distinctive visual style, while remaining easy to replicate, unlike popular Daft Punk builds of years past. Building a replica could serve as good practice before starting out on your own unique build. Video after the break.

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Icosahedron Glows With The Best Of Them

November 22, 2019 by Lewin Day 1 Comment

Glowables come in all shapes and sizes, and we’re always keen to see the multitude of different ways hackers find to put great masses of LEDs to good use. [cabrera.101] wanted to get in on the action, and whipped up a rather flashy icosahedron.

The build uses high-density 144-LED-per-meter strips for the edges, with 60-LED-per-meter strips used for the tubes that connect to the stainless steel ball in the centre. An Arduino Mega controls the Neopixel strips, with the wiring carefully planned out to ensure all LEDs have adequate power and signal to operate correctly. Not one to skimp on the juice, [cabrera.101] outfitted the rig with a 5V, 60A power supply – something that would have seemed ridiculous in 1992, but barely raises an eyebrow today.

It’s a build that would make a perfect whatchamacallit for a science fiction film. The reflections of the edge lights on the central sphere are particularly scintilliating. If you’re new to the realm of glowables, it’s easy to start – there are plenty of tools to help, too. Video after the break.

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Creating Lookalike Valves With Resin Casting

November 21, 2019 by Lewin Day 10 Comments

Valves (tubes) certainly have a die hard fan base in the electronic community, praised for their warm sound, desirable distortion characteristics and attractive aesthetic. However, sometimes you just want the look of a valve for a prop or a toy, without actually needing the functionality. For those cases, this project from [Ajaxjones] might be just the ticket.

The build consists of taking an existing valve, combining it with a 3D printed base, and using this to create a silicone mould. 3D printed parts and dressmaker’s pins are then used to create the internal parts of the valve, and are inserted into the mould. Clear resin is then degassed, and poured into the mould to create the part. Once cured, the part is removed and the base painted to complete the look. An LED is then installed into a void in the base to give the piece a warm glow as you’d expect.

It’s a simple tutorial to producing high-quality clear plastic parts, and one that should prove useful to many prop builders and cosplayers alike. If you’re wanting to take your resin game to the next level, consider trying some overmolded parts. Video after the break.

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Fast Fresnel Hack Embiggens The Smallest Of Heads

November 20, 2019 by Dan Maloney 17 Comments

Aside from frightening small children, we have absolutely no idea why anyone would need a face-magnifying headpiece. But the video below gives us a chuckle every time we see it, and we figure a good laugh that incorporates a quick optics hack is worth a look.

When he’s not playing geek in a box, [Curious Marc]’s videos usually have more of a retrocomputing theme, like his recent conversion of a vintage terminal to a character set from a made-up language, or helping to revive an Apollo Guidance Computer. Given gems like those, we were surprised to learn that [Marc]’s background is physics – optics, to be precise – and that he studied at École Polytechnique, the same school famed physicist Augustin-Jean Fresnel attended. Which fits right into this build since it features one of those large, plastic Fresnel lenses. After a fascinating detour into the history of Fresnel’s namesake lens, [Marc] proceeds with the build.

It’s simplicity itself – a box big enough to wear on the head with one end replaced by the Fresnel lens. A strip of LEDs – warm white, please, lest the wearer takes on a deathly pall – lines the edge of the box just behind the lens. If you want to get fancy, maybe attaching a hard-hat suspension piece would make it more wearable, but even as is it’s just a hoot to see someone with a magnified and distorted head walking around. One probably should be careful not to look at the sun while wearing this, however, for reasons that become apparent beginning at the 3:24 mark of the video.

Thanks to [Marc] for perhaps the oddest YouTube face-reveal yet, and for a great idea for a quick cosplay hack.

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