Where We’re Calculating, We Don’t Need No Seven Segments!

October 18, 2020 by Jenny List 22 Comments

There have been many attempts at electronic numerical display technology over the decades since the first incandescent bulb or neon tube flickered into life at the command of a primordial computer, but the lowest common denominator has remained the humble seven segments. Here it might end, but for [Ken Yap] who has taken inspiration from a 1960s Sharp calculator to re-create a numerical display with only six segments.

This seemingly impossible feat is achieved by having six curved segments arranged as a figure-eight, which can render all the digits after a fashion, but which soon reveals why the extra segment made an appearance. The numbers that are made up of curves look good enough, but the straight lines in the 1, 4, and 7, are compromised by the diagonal, and the zero is curiously small at half the height. You can read the digits, but it takes getting used to.

What made sense to reduce the complexity of 1960s electronics is only a fascinating curiosity in 2020, but we maybe won’t see these displays appearing too often. You can take a look at it in the video below the break, and if you’re curious about the Sharp calculator which inspired it then you can take a look at its page in the Vintage Calculator Museum.

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This Tabletop Lighthouse Will Get Your Attention

October 4, 2020 by Kristina Panos 7 Comments

If you wear headphones around the house with any regularity, you’re probably missing out on a lot of audio cues like knocks at the door, people calling your name, or maybe even the smoke alarm. What if you had a visual indicator of sound that was smart enough to point it out for you?

That is the point of [Jake Ammons’] attention-getting lighthouse, designed and built in two weeks’ time for Architectural Robotics class. It detects ambient noise and responds to it by focusing light in the direction of the sound and changing the color of the light to a significant shade to indicate different events. Up inside the lighthouse is a Teensy 4.0 to read in the sound and spin a motor in response.

[Jake]’s original directive was to make something sound-reactive, and then to turn it into an assistive device. In the future [Jake] would like to add more microphones to do sound localization. We love how sleek and professional this looks — just goes to show you what the right t-shirt stretched over 3D prints can do. Check out the demo after the break.

Seaside lighthouses once used gas lights giant Fresnel lenses, but now they use LEDs. A company in Florida is using CNC machines to crank out acrylic Fresnels.

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An LED Cube To Display CPU Vitals

October 4, 2020 by Lewin Day 10 Comments

LED cubes are all the rage right now. High-end hardware capable of driving large arrays keeps getting cheaper in price, and 3D printers and pre-built boards can make assembly a snap. After attending a major hacker con and seeing the builds on display, [Sebastian] wanted a piece of the action, so set out to build his own.

While many elect to build an LED cube you can hold in your hand, [Sebastian] preferred a stationary tabletop design. This would reduce costs, allowing him to only use 3 LED boards, as the base and remaining two sides would face away from him and not be visible when placed on his desk. The 64×64 arrays are driven by an Adafruit LED matrix bonnet on top of a Raspberry Pi 2. The Pi was a tactical choice, as [Sebastian] had one lying around, and it packed enough processing power to run an OpenGL shader that creates an image for the cube that varies with the CPU load and temperature on his main desktop. As a nice final touch, the Raspberry Pi is set up to have a read-only filesystem. This allows the project to be turned off suddenly without risk of corrupting the SD card.

It’s a tidy build, and one which gives [Sebastian] useful information at a glance. We’ve featured a few stylish cubes before, and even a LED D20 that really breaks the bank. Video after the break.

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Oh, Holey Light

September 30, 2020 by Brian McEvoy 18 Comments

We consider ourselves well-versed when it comes to the technical literature plastered on hardware store parts. Acronyms don’t frighten us, and our Google-fu is strong enough to overcome most mysteries. One bit of dark magic we didn’t understand was the gobbledygook on LED lamps. Wattage is easy and color temperature made sense because it corresponds with warm and cool colors, but Color Rendering Index (CRI) sounds like deep magic. Of course, some folks understand these terms so thoroughly that they can teach the rest of us, like [Jon] and [Kevin], who are building a light controller that corrects inadequacies in cheap lamps by installing several lamps into one unit.

We learned a lot by reading their logs, which are like the Cliff Notes from a lighting engineer’s textbook, but we’ll leave it as an exercise for the students to read through. Their project uses precise light sensors to measure the “flavor” of light coming off cheap lamps so you can mix up a pleasing ratio. In some ways, they are copying the effects of incandescent bulbs, which emit light relatively evenly across the visible light spectrum, right into the infrared. Unfortunately, cheap LEDs have holes in their spectrum coverage, and a Warm White unit has different gaps compared with Daylight, but combining them just right gives a rich output, without breaking the bank.

The Most Expensive D20 You’ll See Today

September 16, 2020 by Brian McEvoy 13 Comments

Roll your negotiation skill, because this d20 is a hefty one. The Tweet is also below. We are charmed by [Greg Davill]’s twenty-sided LED contraption, but what do we call it? Is it a device? A sculpture? A die? Even though “d20” is right on his custom controller PCB, we don’t think this will grace the table at the next elf campaign since it is rather like taking a Rolls Royce to the grocery store. Our builder estimates the price tag at $350 USD and that includes twenty custom PCB light panels with their components, a controller board, one battery pack, and the 3D printed chassis that has to friction-fit the light faces.

Power and communication for all the panels rely on twenty ribbon cables daisy-chained throughout the printed scaffolding, which you can see in the picture above. [Greg] made a six-sided LED cube last year, and there are more details for it, but we suspect he learned his lesson about soldering thousands of lights by hand. There are one-hundred-twenty LEDs per panel, times twenty, that is over two-thousand blinkenlights. We don’t yet have specs on the controller, but last time he used a SAMD51 processor to support over three-thousand lights. We don’t know where he’ll go next, but we’re game if he wants to make a chandelier for Hackaday’s secret underground lair.

(Editor’s Note: If you were at Supercon last year, and you got to play with this thing in the flesh, it’s worth it!)

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LED Art Reveals Itself In Very Slow Motion

September 15, 2020 by Dan Maloney 9 Comments

Every bit of film or video you’ve ever seen is a mind trick, an optical illusion of continuous movement based on flashing 24 to 30 slightly different images into your eyes every second. The wetware between your ears can’t deal with all that information individually, so it convinces itself that you’re seeing smooth motion.

But what if you slow down time: dial things back to one frame every 100 seconds, or every 1,000? That’s the idea behind this slow-motion LED art display called, appropriately enough, “Continuum.” It’s the work of [Louis Beaudoin] and it was inspired by the original very-slow-motion movie player and the recent update we featured. But while those players featured e-paper displays for photorealistic images, “Continuum” takes a lower-resolution approach. The display is comprised of ~~four~~ nine HUB75 32×32 RGB LED displays, each with a 5-mm pitch. The resulting 96×96 pixel display fits nicely within an Ikea RIBBA picture frame.

The display is driven by a Teensy 4 and [Louis]’ custom-designed SmartLED Shield that plugs directly into the HUB75s. The rear of the frame is rimmed with APA102 LED strips for an Ambilight-style effect, and the front of the display has a frosted acrylic diffuser. It’s configured to show animated GIFs at anything from ~~1 frame per second~~ its original framerate to 1,000 ~~seconds per frame~~ times slower, the latter resulting in an image that looks static unless you revisit it sometime later. [Louis] takes full advantage of the Teensy’s processing power to smoothly transition between each pair of frames, and the whole effect is quite wonderful. The video below captures it as best it can, but we imagine this is something best seen in person.

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Digital Pregnancy Tests Use LEDs To Read Between The Lines

September 9, 2020 by Kristina Panos 28 Comments

[Foone] saw a tweet a few weeks ago alleging that digital pregnancy tests are a rip-off. Regular, cheap tests have an absorbent strip running the length of the plastic, with one end exposed for collecting urine. A few excruciating minutes later, a little plastic window in the middle will show one line, two lines, or a plus or minus sign depending on the presence of human chorionic gonadotropin (HCG) in the urine.

As it turns out, at least two digital tests out there are the exact same thing, but with more steps. Instead of a window, they include circuitry that interprets the lines and publishes the result to a little screen in plain English. It can even tell you if you’re doing it wrong by flashing a little RTFM icon.

[Foone]’s teardown reveals a CR1616 coin cell, an 8-bit microcontroller, and a little phototransistor setup that shines LEDs on the strip and reads the incoming light. Unfortunately, the micro is the mask ROM version, so [Foone] can’t reprogram it to run Doom.

The original tweet’s author is probably not alone in assuming that digital tests are supposed to be more accurate somehow. We think the accuracy claim is more about removing the frazzled and/or incompetent human variable from the equation. If the test interprets the results for you, then there’s no mistaking the results, which is technically a higher degree of accuracy. But if you’re in doubt, you get a test from a doctor.

There’s been some discussion about the e-waste aspect of these all these tests — that it’s a shame to produce a microcontroller just to pee on it and throw it away. Sure, you could look at it that way, but unlike a lot of e-waste, these are tools. It’s unfortunate that this is the industry’s idea of higher accuracy, but what should we expect? It’s just testing for the presence of a hormone in urine. Interpreting the results is up to the viewer. We should probably be astounded that they got the cost down to two for $7.

Many people choose to wait a while to start spreading the news. With a Bluetooth-enabled pregnancy test, everyone can find out together.

Thanks for the tip, [Jay]!