Building An Animated Turn Signal For The Mazda MX-5

November 21, 2023 by Lewin Day 37 Comments

Turn signals in most of the world are mandated to be a flashing orange light, distinct from other bulbs on a vehicle. However, there has been a trend in the modern era to go for fancier animated turn signals using great numbers of LEDs. [ssh16] decided to whip up a set of their own to suit their late-model Mazda MX-5.

Fully lit, the replacement is brighter than the original bulb by some margin.

While many builds go down the route of using addressable LEDs, [ssh16] instead went for garden variety OSRAM yellow LEDs in a 3×12 array, driven via a shift register. A small PIC microcontroller is then used to command the shift register to light the rows of LEDs in turn, generating the sequential lighting effect that sweeps from one side to the other. The LEDs are are installed on a 4″ board designed to install in place of the Mazda’s standard indicator bulb, with the animation spreading from the centerline of the vehicle out towards the direction of the turn.

It’s a fun build that modernizes the rear turn signals of the Mazda. We’ve seen some other neat turn signal builds before, too; it almost seems to be a trend amongst Mazda enthusiasts. Meanwhile, if you’ve built your own automotive lighting mods, don’t hesitate to send them in to the tipsline.

How The WS2812 Is Made

November 19, 2023 by Elliot Williams 28 Comments

[Scotty Allen] of Strange Parts is no stranger to Chinese factory tours, but this one is now our favorite. He visits the font of all WS2812s, World Semi, and takes a good look at the machines that make two million LEDs per day.

The big deal with the WS2812s, and all of the similar addressable LEDs that have followed them, is that they have a logic chip inside the LED that enables all the magic. And that means die-bonding bare-die ICs into each blinky. Watching all of the machines pick, place, glue, and melt bond wire is pretty awesome. Don’t miss the demo of the tape-and-frame. And would you believe that they test each smart LED before they kick it out the door? There’s a machine that clocks some data in and reads it back out the other side.

Do we take the addressable LED for granted today? Probably. But if you watch this video, maybe you’ll at least know what goes into making one, and the next time you’re blinking all over the place, you’ll spill a little for the epoxy-squirting machine. After all, the WS2812 is the LED that prompted us to ask, three years ago, if we could live without one.
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Taking A Public Transit Display From Project To Product

November 17, 2023 by Dan Maloney 16 Comments

We’ve noticed an uptick in “project to product” stories lately, which seems like a fantastic trend to us. It means that hackers are turning out projects that really resonate with people, to the degree that taking the leap and scaling up from a one-off to a marketable product is worth the inherent risk. And luckily enough for the rest of us, we get to learn from their experiences.

The latest example of this comes to us from [Stefan Schüller], who from the sound of things only reluctantly undertook the conversion of his LED matrix public transit sign into an actual product. The original project had a lot going for it; it looked fantastic, it was technologically simple, and it provided a valuable service. But as a project, it made certain assumptions and concessions that would cause problems when in the hands of a customer. Chief among these was the physical protection of the fragile LEDs, which could easily shear off the display modules if bumped or dropped. There were also firmware issues, such as access to the backend API that serves the transit data; requiring each customer to sign up for and configure their own API key is a non-starter for a product.

In the article, [Stefan] enumerates a long list of problems that going from project to product raises, as well as how he addressed them. The API issue was solved by implementing his own service, which acts as a middleman between the official API and his customers. A nice plexiglass and sheet-metal frame serves to protect the display, too. Design changes were made as well, not only to provide better functionality but to make manufacturing easier. [Stefan] also relates a tale of woe with regard to getting the display’s app into the app stores, something that few of us have to deal with when we’re just fiddling around with something on the bench.

All in all, [Stefan] does a great job walking us through the trials and tribulations of bringing a product to market. There are similar lessons in this production run scale-up, too, but with an entirely different level of project complexity.

Neopixels? Try Liquid Nitrogen To Color Shift Your LEDs Instead

November 11, 2023 by Dan Maloney 23 Comments

If you’re like us, you’ve never spent a second thinking about what happens when you dunk an ordinary LED into liquid nitrogen. That’s too bad because as it turns out, the results are pretty interesting and actually give us a little bit of a look at the quantum world.

The LED fun that [Sebastian] over at Baltic Lab demonstrates in the video below starts with a bright yellow LED and a beaker full of liquid nitrogen. Lowering the powered LED into the nitrogen changes the color of the light from yellow to green, an effect that reverses as the LED is withdrawn and starts to warm up again. There’s no apparent damage to the LED either, although we suppose that repeated thermal cycles might be detrimental at some point. The color change is quite rapid, and seems to also result in a general increase in the LED’s intensity, although that could be an optical illusion; our eyes are most sensitive in the greenish wavelengths, after all.

So why does this happen? [Sebastian] goes into some detail about that, and this is where quantum physics comes into it. The color of an LED is a property of the bandgap of the semiconductor material. Bandgap is just the difference in energy between electrons in the valence band (the energy levels electrons end up at when excited) and the conduction band (the energy levels they start at.) There’s no bandgap in conductive materials — the two bands overlap — while insulators have a huge bandgap and semiconductors have a narrow gap. Bandgap is also dependent on temperature; it increases with decreasing temperature, with different amounts for different semiconductors, but not observably so over normal temperature ranges. But liquid nitrogen is cold enough for the shift to be dramatically visible.

We’d love to see the color shift associated with other cryogens, or see what happens with a blue LED. Want to try this but don’t have any liquid nitrogen? Make some yourself!

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3D-Printed LED Wall Clock Does Lots With Little

November 6, 2023 by Richard Baguley 14 Comments

This wall clock built by [Alf Müller] is lovely, using two NeoPixel rings to mark the time by casting light onto a 3D-printed ring. The blue shows the minutes, made more discrete by a grid inside the ring. The green shows the hours. [Alf] has provided the code so you can rework the color scheme. It might be interesting to add seconds with the red LEDs, or perhaps a countdown triggered by a touch sensor…

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A Tiny Board For Driving LEDs In…Whatever

October 26, 2023 by Lewin Day 19 Comments

Whether you’re into chiptune or just playing Tetris on original hardware, you might like rocking a heavily-customized Game Boy. Lovely flashing LEDs can only improve the aesthetic, so if that’s what you’re after, you might consider the ARCCore board from [NatalieTheNerd].

The board is a compact and easy way to drive some addressable LEDs, with a form factor designed to take up a small amount of space when stuffed into a Game Boy or other game console. It rocks an RP2040 microcontroller set up to drive a strip of WS2812B LEDs. Three buttons are used to configure the color and brightness settings. The board is designed to run on 3.3 to 5 V, thanks to an onboard buck converter. It’s capable of delivering enough juice to run up to 10 RGB LEDs, though you could potentially use more if you ran them from external power.

You can use just about any microcontroller on the market today to run addressable LEDs if you so desire. If you want a compact drop-in solution that takes up less space, though, you might find the ARCCore useful. If you’ve got your own nifty kit for running addressable LEDs, don’t hesitate to share it with the broader hacker massive — hit the tipsline!

Stage Lighting Hack Keeps La Bohème From Becoming A Dumpster Fire

October 22, 2023 by Dan Maloney 20 Comments

With all due respect to the Utah Opera’s production of La bohème, we just couldn’t resist poking a little fun at master electrician [David Smith]’s quick lighting hack for the opera. And who knew an opera from 1896 would need a garbage can fire? Live and learn.

In what appears to be a case of “The show must go on,” [David] was called on to improve an existing fire effect for one scene in the opera, which was reportedly a bit “artificial and distracting.” This is a pretty common problem in live productions of all types; it’s easy to throw light at a problem, but it’s often hard to make it both convincing and unobtrusive. Luckily, he had both the time to come up with something, and a kit full of goodies to make it happen. A balled-up strip of Neopixels provided the light, with an Arduino running some simple code to randomize the intensity and color of the RGBs. [David] stuck with the warm white, red, and green colors, to keep the color temperature about right for a fire, and drove the LEDs with a couple of MOSFETs that he keeps in his kit to fix busted dimmer packs.

The overall effect worked well, but the holes knocked in the side of the greatly abused garbage can let too much light out, making the effect distracting on stage. The remedy was simple: a cylinder of printer paper surrounding the LED tape. The paper not only acted as a diffuser but held the tape in place inside the can. The electrical crew ran two circuits to the can — one to keep the Arduino running throughout the show, and one to power the LED tape. The former made sure the audience didn’t see the microcontroller boot sequence, and the latter gave the electrician a way to control the effect from the dimmer console. The brief video below shows it in action during a rehearsal.

Hats off to [David] and the whole crew for the stagecraft heroics and for getting this thrown together so quickly.

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