The Eyes Have It With This Solid State Magic Eye

April 12, 2023 by Dan Maloney 8 Comments

The classic “Magic Eye” tuning indicator was a fantastic piece of vacuum tube technology that graced all kinds of electronic gear for a fair fraction of the 20th century. But despite its prevalence, finding a new-old-stock Magic Eye tube is a tall order these days, especially for the rare versions like the 6T5. No worries, though, since direct plug-in solid-state replacements for the 6T5 are now a thing, thanks to [Gord Rabjohn]. Continue reading “The Eyes Have It With This Solid State Magic Eye” →

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.

Spin Up To Speed With This Stroboscope

March 15, 2023 by Bryan Cockfield 3 Comments

A stroboscope is not the most common tool, and while they can be purchased fairly inexpensively from various online stores, they are straightforward enough tools that plenty of us could build our own mostly from parts laying around. The basic idea is to shine a flashing light on a spinning object, and when it appears stationary the stroboscope will indicate the rotational speed. There are a few specialty parts that might not be in everyone’s parts drawers, though, and [John] shows us the ins-and-outs of his own DIY stroboscope.

The effect relies on extremely precise timing, and as such the most important part of a build like this is making sure to get the LED circuitry correct so its duty cycle and frequency can be tightly controlled. [John] is using a PT4115E driver board for the LED, and is using it to power a 1W white LED which also includes its own heat sink and lens. The controls for the stroboscope are handled by an ATtiny1614 microcontroller which shows its pulse rate on a small screen. The user can control the rate the LED flashes with simple controls, and when the spinning object appears to come to a stop the only thing left to do is read this value off of the screen.

While it might seem like an overly niche tool, stroboscopes have plenty of day-to-day uses. Older cars that used a central distributor made use of a specialty stroboscope called a timing light in order to properly advance the ignition timing of the engine. They also retain some use in medical applications, and plenty of older readers may be familiar with their use adjusting the speed on record players. They can also be used to make sure the shutter speeds on cameras are calibrated correctly.

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Adversarial IR Hoodie Lets You Own The Night In Anonymity

March 6, 2023 by Dan Maloney 75 Comments

If you’re in the market for something to obfuscate your nefarious nocturnal activities, rejoice — this adversarial infrared hoodie may be just what you’re looking for.

Not that we condone illegal activities, of course, and neither does artist [Mac Pierce], who created “The Camera-Shy Hoodie.” His purpose seems to be exploring the nature of the surveillance state, or rather to perplex it in the name of anonymity. The idea is simple — equip a standard hoodie with a ring of super-bright IR LEDs, and control them with an RP2040.

We’ve seen blinding hoodies before, but here the LEDs strobe on and off in one of three different patterns, all of which are timed to confound the autoexposure mechanism in just about any surveillance camera by not giving it time to adjust to the rapidly and drastically changing light level. The result is near-total obfuscation of the wearer’s facial features, at least when the camera is in night-vision mode. Check out the results in the video below.

There are some nice touches to [Mac]’s approach, like aluminum PCBs for the LEDs and the use of soldered-on fabric snaps to attach them to the inside of the hoodie, making them easy to remove for laundering. With the LEDs peeking through holes in the fabric, the hoodie looks pretty run-of-the-mill — until, of course, night falls and the USB battery bank in the hoodie’s pocket powers up the light show.

Granted, this won’t exactly help you avoid detection — the big ball of light around your head will be instantly seen by even the most casual observer. But at least it makes it easier to keep your face to yourself. And it won’t help much in daylight — for that, you might want something a little more like this passive adversarial ugly sweater.

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LED Filament Lamp Is Subtle, Warm, And Elegant

February 18, 2023 by Lewin Day 5 Comments

Hackers have loved LEDs from day one, back when they gave us little more than a dim spot of colored light in the darkness. These days, they’re big, bright, and beautiful, and can be used to create some exquisite lighting fixtures. This lamp build from [lonesoulsurfer] is a great example of that.

The build uses LED filaments, which have grown popular for the way they emulate old-fashioned Edison filament bulbs. The filaments consist of tiny LEDs all in a row, covered in flexible material to allow them to act like a filament. They’ll happily power up from just 3V, and deliver great brightness and lovely warm light.

[lonesoulsurfer] bent up an elegant oval-shaped frame for the lamp, using common brass tubing. In the middle of the are two lengths of white plastic tubing with the LEDs inside. The brass is painted black, with the LEDs providing two bright glowing lines on the arms of the oval. The base is then made out of wood and copper tubing, providing a pop of material contrast to the rest of the frame.

It’s an elegant build, and one you can readily recreate at home. If you do so with enough finesse, it will stunt on anything Ikea or (Australian) Kmart has put out in the last decade, in both material quality and uniqueness. We do love a good lamp build around these parts, after all. Video after the break.

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Decorative Clock Uses LED Strips To Beautiful Effect

February 9, 2023 by Lewin Day 19 Comments

Clocks used to be dowdy old things with mechanical hands and sometimes even little cuckoo birds that would pop out to chime the hour. [David] built something altogether more modern that uses shifting colors on LED strips to tell the time.

The core of the build is an ESP8266, which queries an NTP time server to keep itself synced up with the current time as accurately as possible. It then controls a WS2812B LED strip to display the time. The strip itself is hidden in a 3D-printed housing behind an opaque wooden ring, with the light from the LEDs diffusing out nicely on to the wall upon which the clock is mounted.

The display shows three “hands” in the colors it projects on the wall. The red second hand is projected inside and outside the ring. The minute hand is green, and projects outside the ring. Meanwhile, the hour hand is blue, and projects inside the ring. Without any numerical markings, you won’t get an exact reading of the time, but you can figure it out closely enough. As a bonus, the clock looks like a stylish light-based wall sculpture and your guests may not even realizes it tells the time.

We’ve featured [David’s] work before too, in the form of the handy ESP8266 breadboard socket. Video after the break.

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LED Displays May Get Vertical Integration

February 7, 2023 by Al Williams 36 Comments

If you zoom into the screen you are reading this on, you’d see an extremely fine pattern of red, green, and blue emitters, probably LEDs of some kind. This somewhat limits the resolution you can obtain since you have to cram three LEDs into each screen pixel. Engineers at MIT, however, want to do it differently. By growing thin LED films and sandwiching them together, they can produce 4-micron-wide LEDs that produce the full range of color, with each color part of a vertical stack of LEDs.

To put things in perspective, a standard TV LED is at least 200 microns across. Mini LEDs measure upwards of 100 microns, and micro LEDs are the smallest of all. A key factor for displays is the pitch — the distance from the center of one pixel to the center of the next. For example, the 44mm version of the Apple Watch has a pitch of around 77 microns. A Samsung Galaxy 10 is just over 46 microns. This is important because it sets the minimum size for a high-resolution screen, especially if you are building large screens (such as when you build custom video walls (see the video below for more about that).

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