Light-Painting Robot Turns any Floor into Art

Is [SpongeBob SquarePants] art? Opinions will differ, but there’s little doubt about how cool it is to render a pixel-mapped time-lapse portrait of Bikini Bottom’s most famous native son with a roving light painting robot.

Inspired by the recent trend of long exposure pictures of light-adorned Roombas in darkened rooms, [Hacker House] decided to go one step beyond and make a lighted robot with less random navigational tendencies. A 3D-printed frame and wheels carries a pair of steppers and a Raspberry Pi. An 8×8 Neopixel matrix on top provides the light. The software is capable of rendering both simple vector images and rastering across a large surface to produce full-color images. You’ll notice the careful coordination between movement and light in the video below, as well as the impressive turn-on-a-dime performance of the rover, both of which make the images produced so precise.

We’ve covered a lot of light-painting videos before, including jiggering a 3D-printer and using a hanging plotter to paint. But we haven’t seen a light-painter with an essentially unlimited canvas before. We’d also love to see what two or more of these little fellows could accomplish working together.

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The Smartest Smart Watch is the One You Make Yourself

If you’re building a smart watch these days (yawn!), you’ve got to have some special sauce to impress the jaded Hackaday community. [Dominic]’s NeoPixel SmartWatch delivers, with his own take on what’s important to have on your wrist, and just as importantly, what isn’t.

There’s no fancy screen. Instead, the watch gets by with a ring of NeoPixels for all its notification needs. But notification is what it does right. It tells [Dominic] when he’s got an incoming call of course, but also has different flashing color modes for SMS, Snapchat, and e-mail. Oh yeah, and it tells time and even has a flashlight mode. Great functionality for a minimalistic display.

But that’s not all! It’s also got a light sensor that works from the UV all the way down to IR. At the moment, it’s being used to automatically adjust the LED brightness and to display current UV levels. (We imagine turning this into a sunburn alarm mode.) Also planned is a TV-B-Gone style IR transmitter.

The hardware is the tough part of this build, and [Dominic] ended up using a custom PCB to help in cramming so many off-the-shelf modules into a tiny space. Making it look good is icing on the cake.

Thanks [Marcello] for the tip!

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NeoJoints Make WS2812 LEDs Even More Fun

What’s more fun than individually addressable RGB LEDs? Many, many individually addressable RGB LEDs. What’s more fun than all the miscellaneous soldering involved in connecting many of these cheap and cheerful strips together? Well, basically anything. But in particular, these little widgets that [todbot] designed help make connecting up strips of RGB LEDs a snap.

[todbot]’s connectors aren’t particularly groundbreaking, but they’re one of those things that you need the moment you first lay eyes on them. And they’re a testament to rapid prototyping: the mounting holes and improved routing patterns evolved as [todbot] made some, soldered them up, mounted them, and then made some more. We’d like to see some odd angles, of course, but that shouldn’t be too hard to arrange. Everything is up on GitHub, so you can go check it out.

Of course, necessity is the mother of invention, and she’s got many kids. Which is to say that we’ve seen a variation of this hack before precisely because other folks have stared at this matrix-of-strips problem before and come up with similar solutions. Still, we really like the mounting holes and overall aesthetic of [todbot]’s solution, and if you ever find yourself joining WS2812 strips together, give it a try.

Closer Look at Everyone’s Favorite Blinky

Admit it, you love looking at silicon die shots, especially when you have help walking through the functionality of all the different sections. This one’s really easy for a couple of reasons. [electronupdate] pointed his microscope at the die on a WS2812.

The WS2812 is an addressible RGB LED that is often called a Neopixel (a brand name assigned to it by Adafruit). The part is packaged in a 5×5 mm housing with a clear window on the front. This lets you easily see the diodes as they are illuminated, but also makes it easy to get a look at the die for the logic circuit controlling the part.

This die is responsible for reading data as it is shifted in, shifting it out to the next LED in the chain, and setting each of the three diodes accordingly. The funcitonality is simple which makes it a lot easier to figure out what each part of the die contributes to the effort. The diode drivers are a dead giveaway because a bonding wire connected to part of their footprint. It’s quite interesting to hear that the fourth footprint was likely used in testing — sound off in the comments if you can speculate on what those tests included.

We had no trouble spotting logic circuitry. This exploration doesn’t drill down to the gate level like a lot of [Ken Shirriff’s] silicon reverse engineering but the process that [electronupdate] uses is equally fun. He grabs a tiny solar cell and scopes it while the diodes are running to pick up on the PWM pattern used to fade each LED. That’s a neat little trick to keep in your back pocket for use in confirming your theories about clock rate and implementation when reverse engineering someone else’s work.

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WS2812B LED Clones: Work Better Than Originals!

Commodity electronics manufacturing is a tough game. If you come out with a world-beating product, like WorldSemi did with the WS2812B addressable RGB LED “pixel”, you can be pretty sure that you’re going to be cloned in fairly short order. And we’re all used to horror stories of being sold clones instead of what was ordered. But what if the clones were actually an improvement?

[Gonazar] bought some strips of “WS2812” LEDs and prototyped a project. When stepping up to larger production, he thought he’d go directly to WorldSemi. Long story short, the cheaper LED modules that he’d previously bought weren’t from WorldSemi, but were actually SK6812 clones labelled as WS2812Bs. When he switched to the real thing, he discovered that they had some temperature and pressure sensitivities that the clones didn’t. The clones were better!

They weren’t even straight clones. It turns out that they have a much higher PWM frequency, resulting in less flicker at low brightnesses. The distributor came clean, saying that they swapped them out without note because they spoke the same protocol, but were a strict improvement.

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Awesome Illuminated Arcade Spinner

[Tinker_on_Steroids] made some awesome looking spinners that not only light up when spun but are a really professional looking build on their own. Before we’d watched his assembly video we were sure he’d just added on to something he’d bought, but it turned out it’s all custom designed and made.

In case you’ve never played the old arcade games, a spinner is an input device for games such as Tempest or Breakout where you rotate a knob in either direction to tell the game which way and how fast to move something. In Tempest you rotate something around the middle of the screen whereas in Breakout you move a paddle back and forth across the bottom of the playing field.

He even detects rotation with a home-made quadrature encoder. For each spinner, he uses two ITR9608 (PDF) optical switches, or opto-interrupters. Each one is U-shaped with an LED in one leg of the U facing a phototransistor in the other leg. When something passes between the two legs, the light is temporarily blocked and the phototransistor detects it i.e. the switch turns off. When the thing moves away, the light is unblocked and it turns on again. The direction of movement is done by having the thing pass between two ITR9608’s, one after the other. The “things” that pass between are the teeth of a 3D printed encoder wheel. Continue reading “Awesome Illuminated Arcade Spinner”

Smoothly Modernized Nixie Display

The renaissance of Nixie tube popularity amid the nostalgia surrounding older tech has made them almost prohibitively expensive for individual projects. Seeing an opportunity to modernize the beloved devices, [Connor Nishijima] has unleashed this new, LED edge-lit display that he has dubbed Lixie.

We featured his prototype a few years ago. That design used dots to make up each character but this upgrade smooths that out with sleek lines and a look one would almost expect from a professional device — or at the very least something you’d see in a cyberpunk near-future. The color-changing Neopixel LEDs — moderated by a cleverly designed filter — allow for customization to your heart’s content, and the laser-cut acrylic panes allow for larger displays to be produced with relative ease.

The image above (and the video below) show two revisions of the most recent Lixie prototypes. There is a huge improvement on the right, as the digits are now outlines instead of single strokes and engraved instead of cut completely through the acrylic. The difference if phenomenal, and in our opinion move the “back to the drawing board” effect to “ready for primetime”. [Connor] and his team are working on just that, with a Tindie preorder in place for the first production-ready digits to roll off their line.

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