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 36 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.

Continue reading “PCB Makes 7 Segment Displays” →

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!

Continue reading “The Curved Nature Of Time Clock” →

Sailing On A Sea Of Seven-Segment Displays

February 23, 2023 by Dan Maloney 39 Comments

The amount of information the humble seven-segment display can convey is surprising. There are the ten numerals, dead-ringers or reasonable approximations for about half the alphabet, and even a few not-quite-canonical symbols. But when you put 12,288 segments to work, you get all that and much more.

Behold Sea of Segments, an art piece by [Will Gallia] that really pushes what’s possible with seven-segment displays. The piece, which looks about the size of a decent flat-panel TV, is composed of an 8×6 array of PCBs, each of which holds an 8×4 array of white LED seven-segment displays; each board also holds two TLC5920 LED drivers. [Will] designed the PCBs to tile horizontally and vertically, making it possible to take data either from the top or right side and output to the bottom or left. Power is distributed to the modules through a series of steel bus bars, which also provide structural support for the display. The whole thing lives in an enclosure with a smoked acrylic front panel, and hangs from a pair of steel cables that also provide power.

Under the hood, a PocketBeagle does all the heavy lifting of talking to the display and translating images onto the display. [Will] came up with an encoding scheme that gives about five bits of grayscale, and built a program to figure out which segments should be lit to create an image. The result is a smooth and convincing reproduction of videos of waves on a beach, which is where the project gets its name. Check out the results in the video below.

[Will] says he drew inspiration for this build from the DigitGrid by [Skot9000]. That was a great project too, but Sea of Segments takes the concept to another level.

Continue reading “Sailing On A Sea Of Seven-Segment Displays” →

A round clock with a color-coded face, with its name "Pingo" across it, together with a 3D animated mouse

Pingo Is An Analog Clock That Uses Colors Instead Of Hands

February 20, 2023 by Robin Kearey 8 Comments

The purpose of a clock is to show the time, obviously. But if you’ve followed Hackaday for some time, you’ll know there are about a million different ways of achieving this. [illusionmanager] added yet another method in his Pingo Color Clock, which, as the name suggests, uses color as the main indicator.

The clock’s face is divided into three concentric circular zones. The zone at the center shows the hours, while the outer ring indicates the minutes. Both change their color such that they match the zone in between, which always shows a complete rainbow, at the desired location. In the picture above for example, the magenta inner circle matches the rainbow at the 10 o’clock position, while the yellow outer circle matches it at 10 minutes past the hour, meaning it’s currently 10:10.

The rainbow ring is also moving however, and by adjusting its rotation through time you can get some interesting effects. [illusionmanager] programmed it in such a way that the outer ring is always yellow during the day, purple at night, and red at sunrise and sunset. The overall brightness is also adjusted to a day/night schedule.

As complex as the clock’s appearance may be, inside it’s quite a simple design. Nine concentric circular LED strips are driven by an ESP8266, which retrieves the time and sunrise information through its WiFi connection. A piece of translucent white acrylic acts as a diffuser, while a 3D-printed enclosure holds everything together.

Encoding the time using different colors of light has been done before in various different ways, and while we haven’t seen Pingo in real life, we believe it should be somewhat easier to read than most of those examples. It might actually form a nice complement to a recent analog LED ring clock.

Continue reading “Pingo Is An Analog Clock That Uses Colors Instead Of Hands” →

A black chandelier that looks somewhat like a fern frond. It has four lights arranged roughly in a circle around the curly end and two clustered near the tail. It is mounted on a dark wood panel ceiling.

Put A Constellation In Your Dining Room

February 18, 2023 by Navarre Bartz 3 Comments

We love lamps here at Hackaday, especially if they imitate natural light sources. [Scott McIndoe] used his love of lamps to fashion a chandelier replicating his favorite constellation, the Southern Cross.

Starting with the Southern Cross’s four major stars and the pointers of Alpha and Beta Centauri, [McIndoe] sketched out a breaking wave form between the six stars to form the spine of this light source. By using smart bulbs for each of the six star positions, he was able to set a scene that replicates the color and relative brightness of each star for that extra astronomical touch.

The top and bottom of the chandelier is laser cut from 3 mm plywood and fitted together using glue and finger joints while the sides are a wood veneer. The entire piece was sanded and coated with a bit of filler before painting. Mounting is accomplished using three eye hooks mounted on the top side of the chandelier.

If you want more celestial lamps, check out [McIndoe]’s previously-featured analemma chandelier or this lithophane moon lamp.