Give Your Solar Garden Lights A Color Changing LED Upgrade

April 24, 2019 by Roger Cheng 14 Comments

White LEDs were the technological breakthrough that changed the world of lighting, now they are everywhere. There’s no better sign of their cost-effective ubiquity than the dollar store solar garden light: a complete unit integrating a white LED with its solar cell and battery storage. Not content with boring white lights on the ground, [Emily] decided to switch up their colors with a mix of single-color LEDs and dynamic color-changing LEDs, then hung them up high as colorful solar ornaments.

The heart of these solar devices is a YX8018 chip (or one of its competitors.) While the sun is shining, solar power is directed to charge up the battery. Once the solar cell stops producing power, presumably because the sun has gone down, the chip starts acting as a boost converter (“Joule thief”) pushing a single cell battery voltage up high enough to drive its white LED. Changing that LED over to a single color LED is pretty straightforward, but a color changing LED adds a bit of challenge. The boost converter deliver power in pulses that are too fast for human eyes to pick up but the time between power pulses is long enough to cause a color-changing circuit to reset itself and never get beyond its boot-up color.

The hack to keep a color-changing LED’s cycle going is to add a capacitor to retain some charge between pulses, and a diode to prevent that charge from draining back into the rest of the circuit. A ping-pong ball serves as light diffuser, and the whole thing is hung up using a 3D-printed sheath which adds its own splash of color.

Solar garden lights are great basis for a cheap and easy introduction to electronics hacking. We’ve seen them turn into LED throwies, into a usable flashlight, or even to power an ATTiny microcontroller.

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Mini Flickering Torch Effect Uses Neither Wires Nor Solder

April 15, 2019 by Donald Papp 8 Comments

[ROBAGON] makes miniature, 3D-printable gaming terrain and features like these stone pillars with flickering torch. His model isn’t free to download (though it’s under $2 at the time of writing), but the part that impressed us was his clever way of using electric tea lights to create a flickering torch effect without needing any soldering or wiring whatsoever.

His solution was to make the base of the pillar large enough to fit an electric tea light, which uses a flickering LED to simulate a candle flame. The molded plastic “flame” is removed from the tea light and placed in the torch sconce, while the tea light itself goes into the base. A short segment of clear acrylic rod is used as a light pipe, running from the tea light’s LED to the base of the torch.

It’s a simple, effective, and economical solution that doesn’t require running or soldering a single wire and you can see it work in the brief video embedded below. Now all that’s missing for those Dungeons & Dragons sessions is this custom calculator.

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Replicating 1970s LED Displays

April 14, 2019 by Brian Benchoff 13 Comments

In 1971, Texas Instruments released something no one else had ever seen before. The TIL305 was an alphanumeric display, powered by LEDs. Sure, the technology of the early 70s meant the LEDs weren’t very bright, and the displays were expensive, but if you want a display that’s simply classic, and relatively low-power, you won’t be able to do better than a vintage alphanumeric LED display.

As you would expect, new old stock TIL305s are still pricey, and now everybody has access to cheap PCB manufacturing capabilities and really small LEDs. The DIYTIL305 is an attempt to replicate the vintage stuff, and it looks great.

The vintage, TI-made TIL305 is a printed circuit board that clips into a DIP-14 socket. The LED array is 5×7 pixels, with an extra dot for a decimal point, set on a 0.05″ grid, and a translucent red diffuser. A PCB is easy, and with 0201 LEDs you can get the LED pitch you need. Turning a PCB into a DIP-14 only requires a few machine pin headers, and for the diffuser, this project is using laser cut cast acrylic. It’s simple if you have a pick and place machine or a steady hand, and assembly is a snap.

The final DIYTIL305 boards are being tested right now, but so far the results are great. With the right code on a microcontroller, these displays will blink through the digits 0 through 9, and the alphabet is just a little more code. Since this project is using 0201 LEDs, it also means green, white, blue, orange, and yellow displays are possible, something no one could have dreamed of in 1971.

Bringing A Child’s Play Kitchen To Life

April 14, 2019 by Tom Nardi 7 Comments

Given how many adults will go out of their way to avoid spending any extended amount of time in the kitchen, it’s pretty amazing how much children love playing in their miniature versions. Especially since they tend to be pretty simple: usually they’re little more than different sized boxes made out of MDF to represent the refrigerator, oven, and microwave. Of course, some kids are fortunate enough to have hackers and makers for parents.

[Brian Lough] wanted to get his two year old daughter her own play kitchen, but wasn’t terribly impressed with anything on the market. So he decided to start with the IKEA Duktig and add in his own personal touches to turn the stark white playset into something that would really get his daughter’s imagination going. With the liberal application of RGB LEDs and microcontrollers, her kitchen is sure to be envy of the sandbox.

Being the class act that he is, [Brian] starts his write-up acknowledging the various IKEA Duktig hacks and modifications that served as inspiration for his own build. Most of the prior art out there relates to making the microwave and oven a bit more exciting with the addition of lights and sounds, which ultimately ended up being the way he approached his daughter’s version as well.

For the oven, [Brian] decided to add some big arcade buttons over the door which would change the color of the RGB LEDs inside. He thought this association would be a good way to help his daughter learn her colors, since she’ll be able to see the oven change color when she presses the corresponding button. He also added a knob to control the intensity of the light, meant to be analogous to the temperature control in a real oven.

The modifications to the microwave are a bit more extensive, including a “timer” made out of a TM1637 LED display in a 3D printed panel complete with a buzzer to indicate when the plastic food has been thoroughly illuminated. [Brian] even made it so the LEDs in the NeoPixel ring light up in a spinning pattern to cast some shadows and simulate movement. He notes that the microwave was actually a bit overwhelming to his daughter at first, but after a couple months of getting used to the functions, she enjoys it as much as the oven.

While hacking a play kitchen might be new territory for him, [Brian] is no stranger to building awesome stuff. We’ve previously seen him put together a YouTube subscriber counter in the style of Tetris, and he even managed to create a gorgeous looking display out of shoelaces of all things.

The Display For When You Want Nixies Without All The Hassle

April 9, 2019 by Brian Benchoff 20 Comments

If you want to display numbers, just go for Nixies. There’s no better way to do that job, simply because they look so cool. Unfortunately, Nixies require high voltages, controlling them is a tiny bit strange, and they suck down a lot of power. These facts have given us a few Nixie alternatives, and [Dave] is here with yet another one. It’s a light pipe Nixie, made from acrylic rod.

The idea of using lights shining into a piece of acrylic to display a number is probably as old as the Nixie itself. There were a few tools in the 60s that used side-lit plastic panels to display numbers, and more recently we’ve seen a laser-cut version, the Lixie. This display is just ten sheets of acrylic etched with the numbers 0 through 9. Shine a light through the right acrylic sheet, and that number lights up.

You can do just about everything in acrylic, and it’s already used for a light pipe, so [Dave] grabbed some acrylic rod and bent it into the shape of a few numbers. With a little work, he was able to make his own FauxNixie by mounting these numbers in a carefully modified lamp socked wired up with ten individual LEDs. The results make for big, big, big Nixie-style numbers, and the perfect clock for the discerning glowey aficionado.

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Arcade With LED Marquee Shows Off Your Game

April 4, 2019 by Tom Nardi 9 Comments

We’ve seen a lot of arcade machine builds here on Hackaday. Seriously, a lot. Even more so since the Raspberry Pi took over the world and made it so you didn’t have to cannibalize an old laptop to build one anymore. It’s one of those projects with huge appeal: either you’re somebody who’s built their own arcade, or you’re somebody who wishes they had. But even after seeing all these builds, we occasionally come across a specimen that deserves special recognition.

[Al Linke] recently wrote in to tell us about his arcade build, which we think you’ll agree is worth a closer look. The core build is actually a modification of a previously published design, but what makes this one unique is the addition of a programmable LED matrix in the top that actually shows the logo and artwork for whatever game you’re currently playing. This display really helps sell the overall look, and instantly makes the experience that much more authentic. Sure you don’t need the marquee of your home arcade machine to show era-appropriate artwork…but we know you want it to.

So how does one interface their Raspberry Pi with this beautiful 64×32 LED marquee display? Well it just so happens that [Al] is in the business of making cool LED displays, and even has a couple successful Kickstarter campaigns under his belt to prove it. He’s developed a board that lets you easily connect up to low-cost HUB75 LED panels such as the one used in the arcade. It’s been a few years since we’ve last seen a project that tackled these specific LED displays, and it’s encouraging to see how far things have come since then.

Even if you’re somehow not in love with the LED marquee, this build really does stand on its own as a fantastic example of a desktop arcade machine. [Al] went to great length to document his build, including putting together several videos during different phases of construction. If you’re curious about the start of the art for home arcade builds, this project would be a pretty good one to use as a barometer.

Whether it’s a full-size replica of the machine you spent your youth standing in front of, or an entirely new design made to your exacting specifications, there’s few projects that are a better conversation starter than one of these beauties blinking away in your living room.

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[Caleb Kraft] Brings Us The Moon, On A Budget

March 29, 2019 by Tom Nardi 17 Comments

As you might expect from one of our most illustrious alumni, [Caleb Kraft] is a rather creative fellow. Over the years he’s created some absolutely phenomenal projects using CNC routers, 3D printers, laser cutters, and all the other cool toys the modern hacker has access to. But for his latest project, a celebration of the full Moon, he challenged himself to go low-tech. The Moon is something that anyone on Earth can look up and enjoy, so it seemed only fitting that this project should be as accessible to others as possible.

[Caleb] started this project by looking for high-resolution images of the Moon, which was easy enough. He was even able to find sign shops that were more than happy to print a giant version for him. Unfortunately, the prices he was quoted were equally gargantuan. To really be something that anyone could do, this project needed to not only be easy, but as affordable as possible. But where do you get a giant picture of the Moon for cheap?

He eventually found a source for Moon shower curtains (we told you he was creative), which fit the bill perfectly. [Caleb] says they aren’t nearly as detailed as the original images he found, but unless you’ve got your face pressed up against it you’ll never notice anyway. To make the round frame, he used PEX tubing from the hardware store and simply stapled the curtain directly to the soft plastic. The hardest part of the whole project is arguably getting the curtain flat and taut on the PEX ring.

Technically you could stop now and have a pretty slick piece of art to hang on your wall, but [Caleb] took the idea a bit farther and put a strip of RGB LEDs along the inside of the ring. The shower curtain material does a decent enough job of diffusing the light of the LEDs to make it look pretty good, though there’s certainly some room for improvement if you want to get a more even effect over the entire surface. While you’re at it, you might as well add in some additional electronics so the lighting matches the current phase of the real-life Moon.

On the other hand, if you’re willing to settle for a far more diminutive version of Luna and don’t mind using those highfalutin hacker tools that [Caleb] decided to avoid for the good of mankind, we’ve got a project you might be interested in.

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