Trick Your (1970) Pickup Truck

March 26, 2024 by Al Williams 24 Comments

[Dave] wanted an old pickup, and he found a GMC Sierra Grande truck vintage 1970. While it had an unusual amount of options, there weren’t that many high-tech options over 50 years ago. The five-year-long restoration work was impressive, as you can see in the video below, but we were really interested in the electronics part. As [Dave] mentions, the truck was made when the Saturn V was taking people to the moon, but after his modifications, the truck has a lot more computing power than the famous rocket.

He was concerned that the taillights were not up to modern standards and that it would be too easy for someone using their cell phone to plow into the rear of the truck. So he broke out an ESP32 and some LEDs and made an attractive brake light that would have been a high-tech marvel in 1970.

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Optical Guitar Pickup Works With Nylon Strings

March 4, 2024 by Lewin Day 67 Comments

Electric guitar pickups rely on steel strings interfering with a magnetic field, the changes in which are picked up with coils of wire. That doesn’t work with nylon strings, because they don’t tend to perturb magnetic fields nearly as much, beyond some infinitesimal level that some quantum physicist could explain. So what do you do? You follow [Simon]’s example, and build an optical pickup instead.

The concept is simple. You place an LED and a phototransistor in a U-shaped channel, and place it so that the string runs through it. You repeat this for each string. Thus, as a string vibrates, it interrupts the light travelling from the LED to the phototransistor. This generates a voltage that varies with the frequency of the string’s vibration. Funnily enough, this type of pickup will work just fine on both nylon and steel strings, if you were so inclined to try it.

[Simon] designed a nifty PCB with six LED-phototransistor pairs (using off-the-shelf interruptor sensors) for use with a nylon-stringed guitar. He reports that sound from the strings comes through clearly, but that there is some noise that is evident in the pickup’s output, too. Listening to the demo, it seems to capture the sound of the nylon strings well, it’s just a shame that the noise floor is so high.

If you prefer your guitar pickups to be the regular magnetic kind, you can always wind your own from scrap. Demo after the break.

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The Photodiode You Never Knew You Had

February 28, 2024 by Jenny List 34 Comments

Optoelectronics hold a range of possibilities for the hardware experimenter — indeed who among us hasn’t added LEDs aplenty to our work? What many of us may be unaware of though is that an LED is also a photodiode, and can even be persuaded to generate usable quantities of power. [Voltative] takes a look at this phenomenon with a series of experiments.

Lighting up an LED from a set of other LEDs is pretty cool, as is powering a calculator, or even the calculator powering itself from its on-board LED. But what caught our eye was using two LEDs as a data link, with both of them acting as transmitter and receiver (something on searching we find we’ve seen before). The possibilities there become interesting indeed.

Given that we are now surrounded by LEDs, from OLED screens to LED lighting, we can’t help wondering what the photodiode performance of some other types of part might be. Would the large area of a lighting LED give a better result for example, or would the phosphorescent coating of a white LED make it useless. We feel there’s more scope for experimentation here.

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LED Matrix Earrings Show Off SMD Skills

February 21, 2024 by Dan Maloney 12 Comments

We’ll be honest with you: we’re not sure if the use of “LED stud” in [mitxela]’s new project refers to the incomprehensibly tiny LED matrix earrings he made, or to himself for attempting the build. We’re leaning toward the latter, but both seem equally likely.

This build is sort of a mash-up of two recent [mitxela] projects — his LED industrial piercing, which contributes the concept of light-up jewelry in general as well as the power supply and enclosure, and his tiny volumetric persistence-of-vision display, which inspired the (greatly downsized) LED matrix. The matrix is the star of the show, coming in at only 9 mm in diameter and adorned with 0201 LEDs, 52 in total on a 1 mm pitch. Rather than incur the budget-busting expense of a high-density PCB with many layers and lots of blind vias, [mitexla] came up with a clever workaround: two separate boards, one for the LEDs and one for everything else. The boards were soldered together first and then populated with the LEDs (via a pick-and-place machine, mercifully) and the CH32V003 microcontroller before being wired to the power source and set in the stud.

Even though most of us will probably never attempt a build on this scale, there are still quite a few clever hacks on display here. Our favorite is the micro-soldering iron [mitxela] whipped up to repair one LED that went missing from the array. He simply wrapped a length of 21-gauge solid copper wire around his iron’s tip and shaped a tiny chisel point into it with a file. We’ll be keeping that one in mind for the future.

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Shuji Nakamura: The Man Who Gave Us The Blue LED Despite All Odds

February 14, 2024 by Maya Posch 68 Comments

With the invention of the first LED featuring a red color, it seemed only a matter of time before LEDs would appear with other colors. Indeed, soon green and other colors joined the LED revolution, but not blue. Although some dim prototypes existed, none of them were practical enough to be considered for commercialization. The subject of a recent [Veritasium] video, the core of the problem was that finding a material with the right bandgap and other desirable properties remained elusive. It was in this situation that at the tail end of the 1980s a young engineer at Nichia in Japan found himself pursuing a solution to this conundrum.

Although Nichia was struggling at the time due to the competition in the semiconductor market, its president was not afraid to take a gamble on a promise, which is why this young engineer – [Shuji Nakamura] – got permission to try his wits at the problem. This included a year long study trip to Florida to learn the ins and outs of a new technology called metalorganic chemical vapor deposition (MOCVD, also metalorganic vapor-phase epitaxy). Once back in Japan, he got access to a new MOCVD machine at Nichia, which he quickly got around to heavily modifying into the now well-known two-flow reactor version which improves the yield.

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Building Nanoleaf-Inspired Wall Panels That Look Great

January 28, 2024 by Lewin Day 12 Comments

Nanoleaf is well-known as being that company that makes those lovely glowing tiles that you can hang on your wall. The only thing is, they’re not cheap. So if you want a really cool layout, you have to spend a great amount of money. [Projects with Red] was inspired by the basic concept, though, and whipped up their own gem-shaped wall tiles along similar lines.

The devices can work as a big clock if you so desire.

The irregular hexagon shape of each gem has ten connection points to attach the segments together. Physical connections are made using the 3D printed housings of each segment, while connections are simply made with wires and connectors hanging out the back for flexibility.

Each segment features a black printed housing with a solid lid and a translucent acrylic sheet to act as a diffuser. An addressable LED strip is mounted to the lid for illumination, with Dupont connectors for hooking them up to power and data. An ESP32 is used to drive the addressable LED chain, running the WLED.me software for easy control of the lights and animations. The video below also explains how to configure the segments into a giant colorful 7-segment display.

It’s a neat way to build some LED wall art, with plenty of scope to reconfigure it to suit your own needs. We’ve seen some other fun LED tile projects before, too.
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Is This The World’s Smallest N-Scale Train Layout?

January 23, 2024 by Kristina Panos 7 Comments

There’s just something about miniature worlds — they’re just so relaxing to look at and ponder. Think you don’t have ample room for a model train layout at your place? You may not be thinking small enough. [Peter Waldraff] knows a thing or two about hiding train layouts inside of furniture (that’s one solution), but this time, he’s built a track in plain sight that’s meant to sit on the bookshelf. The whole thing is just 5.5″ x 12″.

This N-scale layout was three years in the making, mostly because [Peter] was waiting for just the right little powered chassis to come along. For the layout, [Peter] started by creating custom flexible track by removing pieces with a sharp knife. He glued down the track to pink foam and used nails to hold it in place while the glue dried. He also built a wood frame around the base to stabilize it and hold some of the electronic components, including a switch made from an old ballpoint pen.

Then it was time to start decorating the thing, beginning with a couple of buildings made from more pink foam that are both lit up with LEDs. Eventually, [Peter] added a bunch of details like streetlights, animals, and garbage cans that really make the layout pop. As far as the engine goes, [Peter] picked up a Tomytec TM-TR02 on eBay and built a trolley out of two broken cars. [Peter]’s build is something you just have to see for yourself — fortunately for you, the build and demo video is after the break.

Like we said, [Peter]’s usual territory is hiding train layouts in end tables and coffee tables and the like, so it’s nice to see what he can do given different constraints.

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