Smooth Animations, Slick Bar Graphs, But No Custom Characters On This 16×2 OLED

April 27, 2023 by Dan Maloney 7 Comments

Sometimes, finding new ways to use old hardware requires awesome feats of reverse engineering, software sleight of hand, and a healthy dose of good fortune. Other times, though, it’s just as simple as reading the data sheet and paying attention to details.

Not that we’re knocking [upir]’s accomplishment with these tricked-out 16×2 OLED displays. Far from it, in fact — the smoothly animated bar graph displays alphanumerics look fantastic. What’s cool about this is that he accomplished all this without resorting to custom characters. We’ve seen him use this approach before; this time around, the hack involves carefully shopping for a 16×2 OLED display with the right driver chip — a US2066 chip. You’ll still need a few tricks to get things working, like extra pull-up resistors to get the I2C display talking to an Arduino, plus a little luck that you got a display with the right character ROM.

Once all that is taken care of, getting the display to do what you want is mainly a matter of coding. In the video below, [upir] does a great job of walking through the finer points, and the results look great. The bar graphs in particular look fantastic, with silky-smooth animations.

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3D printed Hagrid's lantern with a magic wand

Micro:bit Brings 3D Printed Magic Lanterns To Life

April 18, 2023 by Orlando Hoilett 1 Comment

[Elenavercher] loves engaging her primary school students, inspiring their imagination as well as teaching them the design thinking process. She has found that the very accessible rapid prototyping culture of 3D printing, micro:bit, and the like are perfect for teaching her students problem-solving and teamwork, and is always coming up with new lessons that will catch their attention. That brings us to her latest design, an interactive lantern and wand, which you could say is of the wizarding variety.

The lantern and the wand each have an integrated micro:bit serving as their brains. When the user shakes the wand, releasing a spell, the micro:bit in the wand, sends a user-defined number to the micro:bit in the lantern. The lantern has NeoPixels built-in, which then turn on, illuminating the lantern. When the user presses a button on the micro:bit instead of shaking it, the wand sends a signal to the lantern that tells it to “turn off.” Pretty simple, right?

The design itself is something any seasoned hacker could recreate; however, the magic in this build is how [Elenavercher] beautifully engages her elementary-aged students in the engineering design process. She starts off by encouraging her students to prototype the lantern and wand using paper which is a very inexpensive way to help them visualize the final product before investing too much time into the 3D design, a critical engineering design step — prototype fast and cheap with whatever you have on hand.

She then helps them design the lantern and wand in Tinkercad, a very beginner-friendly, yet increasingly capable CAD program. We really appreciate her detailed steps for the design as well as for navigating Tinkercad, both of which will help teach any tiny tikes in your life how to recreate the design. What’s really handy about Tinkercad is you can do mechanical CAD as well as write code for the micro:bit all within the same program. But [Elenavercher] also provides the final .hex file if you’d rather just get the build up and running.

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IOT Message Board Puts Fourteen-Segment Displays To Work

March 28, 2023 by Dan Maloney 4 Comments

We’re not sure, but the number of recognizable alphanumeric characters that a seven-segment display can manage seems to have more to do with human pattern recognition than engineering. It takes some imagination, and perhaps a little squinting, to discern some characters, though. Arguably better is the fourteen-segment display, which has been pressed into service in this just-for-funsies IOT message board.

As [Steve] tells the story, this is one of those “boredom-buster” projects that start with a look through the junk bin to see what presents itself. In his case, some fourteen-segment common-cathode LEDs presented themselves, and the result was a simple but fun build. [Steve] used some clever methods to get the display stuffed onto two protoboards, including mounting the current-limiting resistors cordwood-style between the boards. A Raspberry Pi drives the display through a very neatly routed ribbon cable, and the whole thing lives in a tidy wooden box.

The IOT part of the build allows the display to show messages entered on [Steve]’s web page, with a webcam live stream to close the loop. Strangely, the display seems stuck on the “HI HACKADAY!” we entered as a test after [Steve] tipped us off, so we’re not sure if we busted it or what. Apologies if we did, [Steve]. And by the way, if your cats are named [Nibble] and [Pixel], well done!

No matter what you do with them, multi-segment displays are pretty cool. But if you think they’re something new, you’ve got another think coming.

Three Way LED Bulb Gives Up Its Secrets

March 14, 2023 by Al Williams 18 Comments

You’ve probably seen three-way bulbs. You know, the ones that can go dim or bright with each turn of a switch. [Brian Dipert] wondered how the LED version of these works, and now that he tore one apart, you can find out, too. The old light bulbs were easy to figure out. They had two filaments, one brighter than the other. Switching on the first filament provided some light, and the second gave off more light. The final position lit both filaments at once for an even brighter light.

LED or filament, three-way bulbs have a special base. While a normal Edison-base bulb has the threaded part as the neutral and a center contact for the live wire, a three-way bulb has an extra hot contact ring between the threaded part and the center contact. Obviously, a compatible LED bulb will need this same interface, but will work differently inside.

Inside the LED, [Brian] found two rings of LEDs that took the place of the filaments. He was able to identify all the ICs and devices on the board except one, an MT7712S. If you can read Mandarin, we think this is the datasheet for it.

We weren’t sure what [Brian] would find inside. After all, you could just sense which contacts had voltage and dim the LEDs using PWM. It probably wouldn’t take any less circuitry. LED lighting is everywhere these days, and maybe they don’t all work the same, but you have to admit, using two strings of LEDs is reasonably faithful to the old-fashioned bulbs.

Sometimes LED bulbs are different depending on where you buy them. We were promised LED bulbs would never burn out. Of course, they do, but you can usually scrounge some LEDs from them.

A Hacker’s Introduction To DIY Light Guide Plates

March 13, 2023 by Sonya Vasquez 37 Comments

Last year, I found myself compelled to make a scaled-down replica of the iconic test chamber signs from the video game Portal. If you’ve played the game, you’ll remember these signs as the illuminated monoliths that postmarked the start of every test chamber. In hyperstylized video game fashion, they were also extremely thin.

https://www.thonky.com/portal-walkthrough/test-chamber-19 — Stay tuned for cake at the end of this article.

True to the original, my replica would need to be both slimmed down and backlit with a uniform, natural white glow. As fate would have it, the crux of this project was finding a way to do just that: to diffuse light coming in from the edges so that it would emit evenly from the front.

What I thought would be quick project ended up being a dive down the rabbit hole that yielded some satisfying results. Today, I’d like to share my findings and introduce you to light guide plates, one of the key building blocks inside of much of today’s backlit screen technology. I’ll dig into the some of the working principles, introduce you to my homebrew approach, and leave you with some inspirational source code to go forth and build your own. Continue reading “A Hacker’s Introduction To DIY Light Guide Plates” →

PCB Makes 7 Segment Displays

March 3, 2023 by Al Williams 9 Comments

Of course, there’s nothing unusual about using 7-segment displays, especially in a clock. However, [Edison Science Corner] didn’t buy displays. Instead, he fabricated them from a PCB using 0805 LEDs for the segments. You can see the resulting clock project in the video below.

While the idea is good, we might have been tempted to use a pair of LEDs for each segment or used a diffuser to blur the LEDs. The bare look is nice, but it can make reading some numerals slightly confusing.

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The Curved Nature Of Time Clock

March 3, 2023 by Al Williams No comments

While we’re told that space-time curves, we aren’t sure that was what [andrei.erdei] was going for when he built a great-looking curved LED clock. The LEDs are courtesy of a strip of 84 WS2812 smart LEDs, the curve comes from a 3D printed part, and a Wemos D1 mini provides the brains.

Like all of our favorite clocks, this one has a unique way of displaying the time. If you find the description in the post hard to understand, the video below makes it a bit easier to wrap your head around. Note the time appears in the top left corner of the video in several cases — so you can check to see if you’re reading it correctly.

The secret sauce, of course, is the curved plastic grid that holds the LEDs. Because of the unusual shape, supports are a must and there are notes in the post about the settings used to get the best results. With 84 LEDs, the software has to be careful not to turn them to full brightness at one time, or else the clock would need a 6 amp power supply. Instead, the software limits the brightness to a little less than half of the maximum. No LED is ever white, and not all LEDs are on at once. The clock works easily, according to [andrei], with a 2 A supply. The clock has a WiFi connection where you can set things up easily.

Overall, a nice-looking project that would look at home on a science fiction movie set. We’ve seen color clocks before. If you want to economize on LEDs, we’ve seen a clock with only five!

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