Table Tennis Ball Lamp Serves Up Style

April 11, 2020 by Kristina Panos 5 Comments

Although RGB LEDs diffused by ping pong balls will probably never stop being cool, [thomasj152] feels that flat panels of balls have become a bit of a tired concept. After a lot of effort and two complete builds, he has spun up an 80-ball spherical lamp. The results are positively glowing!

All the balls are connected together with some clever 3D printed pieces that were inspired by the classic soccer ball layout of hexagons and pentagons. [thomasj152] chose this shape because it’s fairly easy to code animation sequences for it.

The design also breaks down nicely into two halves, which makes it easier to wire. All 80 of the balls are controlled with a single NodeMCU ESP8266 development board.

This stranded version is the second lamp [thomasj152] built. The first one used the same soccer ball style, but had RGB LED strips instead, and the balls were wrangled with laser-cut support pieces. Strips lay much flatter than strands do, leaving the inside tidy and spacious. Unfortunately, the LED strips got fried accidentally, which is extra sad because the strips version looks like way more work.

The bright spot here is that [thomasj152] can now provide instructions for both versions. He even has code that cycles through each pentagon and hexagon section, lighting them up one at a time for testing and sanity checks. Roll past the break for a walk-through video that shows both versions and explains the differences.

Got a bunch of wall space begging for blinkenlights? Apparently it’s possible to throw together a working 300-ball video wall in less than 24 hours. Who knew?

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The Key To This City Opens A Real Lock

April 11, 2020 by Jenny List 6 Comments

There are few more satisfying moments than the first time you pick a lock. No matter that it’s a dollar-store padlock that you opened with a pick from a $10 eBay kit, the magic of something that should be secure clicking open in the palm of your hand is hard to beat. Pin tumbler locks are surprisingly simple devices, and to demonstrate this [Farmcraft 101] has produced one at 10x scale to demonstrate their operation on the bench.

The video is a delightful exercise in wood-shop voyerism, as we see him construct the various parts of the lock using his lathe and other workshop tools. A key of the size usually reserved for Freedom Of The City is made, but this one really does slide into the keyway and operate those pins. At the back is a latch mechanism, and the result is a fully-functional model that anyone should be able to use to figure out how the lock works.

Thelock itself isn’t the whole story though, because given the date he’s used it as the basis for a cracking April Fool in which he sends up the [Lock Picking Lawyer] and proceeds to demonstrate the glaring insecurities in his creation. Both videos are there for your enjoyment, below the break. And if you can’t wait to have a go at a lock or two, don’t forget you can always make your own tools using paperclips.

[Ed note: streetcleaner bristles. Thank me later.]

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Harvesting Energy From Ambient Moisture

April 11, 2020 by Danie Conradie 24 Comments

Generating electricity out of thin air is the fantasy for our modern technology dependant world, but still falls squarely in the world of science fiction. However, researchers from the University of Massachusetts Amherst claim that they have found a way to do exactly that, using protein nano-wires to produce tiny amounts of electricity from ambient humidity.

The protein nano-wires in question are harvested from the microbe Geobacter sulfurreducens, to create a 7 µm thick film that is placed between two gold electrodes. One electrode completely covers the back of the film, while the front electrode covers only a tiny portion of the surface area. When the film is exposed ambient moisture, researchers measured 0.4 V – 0.6 V produced continuously for more than two months. The current density was about 17 µA/cm². This is only a fraction of the output of a commercial solar panel, but it can be layered with air gaps in between. The electricity is supposedly produced due to a moisture gradient through the thickness of the film. Harvesting energy using ambient humidity is not new, but the improvement in power density on this study is at least two orders of magnitude larger than that of previous studies.

The researches have named the technology Air-Gen and hope to develop it commercially. As we have seen many times before, promising lab results often don’t translate well into real world products, but this technology is definitely interesting.

We’ll continue to see all sorts of weird and wonderful ways to free up electrons, like using sweat, but we’ll have to wait and see what sticks.

Thanks for the tip [William Polo]!

Planetary Gears Tell Time In This Ornamental Clock

April 10, 2020 by Moritz v. Sivers 8 Comments

A clock is perhaps one of the the most popular projects among makers. Most designs we see are purely electronic and do not bother with the often more complicated mechanical part. Instructables user [Looman_projects] though was not afraid of calculating gear ratios and tooth counts for his planetary gear clock.

As shown in the picture, a planetary gear, also known as epicyclic gear, consists of three parts: a central sun gear, planetary gears moving around the sun gear and an outer ring with inward-facing teeth holding it all together. The mechanism dates back to ancient Greece but is still being used in car transmissions and has become quite popular in 3D printing. In his instructable [Looman_projects] has some useful inlinks including an explanation video of how planetary gear sets work and a website helping you to calculate the tooth counts for specific gear ratios. It is also noteworthy that he tried to cut the gears from aluminum with a waterjet which unfortunately failed because the parts were too small. What makes the clock visually stand out is the beautiful ornamental see-through design of the dial plate and hands made from laser-cut wood. Despite the mechanical gearbox, it is not surprising that the driving mechanism is based on ubiquitous pieces of digital electronics including an Arduino Nano, DS3231 RTC module, and a stepper motor. To avoid a cabling mess [Looman_projects] designed a custom PCB that interconnects all the electronics and says he even got some spare PCBs left for people interested in rebuilding the clock.

Actually, this is not the first laser-cut planetary gear clock that we have seen. In case you are wondering about the advantages of planetary gearboxes, you might want to check out how a 3D printed version is lifting an anvil.

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Background Substitution, No Green Screen Required

April 10, 2020 by Dan Maloney 28 Comments

All this working from home that people have been doing has a natural but unintended consequence: revealing your dirty little domestic secrets on a video conference. Face time can come at a high price if the only room you have available for work is the bedroom, with piles of dirty laundry or perhaps the incriminating contents of one’s nightstand on full display for your coworkers.

There has to be a tech fix for this problem, and many of the commercial video conferencing platforms support virtual backgrounds. But [Florian Echtler] would rather air his dirty laundry than go near Zoom, so he built a machine-learning background substitution app that works with just about any video conferencing platform. Awkwardly dubbed DeepBackSub — he’s working on a better name — the system does the hard work of finding the person in the frame with Tensorflow Lite. After identifying everything in the frame that’s a person, OpenCV replaces everything that’s not with whatever you choose, and the modified scene is piped over a virtual video device to the videoconferencing software. He’s tested on Firefox, Skype, and guvcview so far, all running on Linux. The resolution and framerates are limited, but such is the cost of keeping your secrets and establishing a firm boundary between work life and home life.

[Florian] has taken the need for a green screen out of what’s formally known as chroma key compositing, which [Tom Scott] did a great primer on a few years back. A physical green screen is the traditional way to do this, but we honestly think this technique is great and can’t wait to try it out with our Hackaday colleagues at the weekly videoconference.

Seven-Segment Single-Steps Through The Time

April 10, 2020 by Kristina Panos 9 Comments

Have you ever looked at the time, and then had to look again because it just didn’t register? This phenomenon seems more prevalent with phone timepieces, but it’s been known to happen with standard wall clocks, too. This latest offering in a stream of unusual clocks fashioned by [mircemk] solves that problem by forcing the viewer to pay attention as the time flashes by in a series of single digits, separated by a hyphen.

Inside the boxy blue base is an Arduino Nano, a DS3231 real-time clock module, and a perfboard full of transistors for switching the LED strips inside the segments. There’s an LED on the front that blinks the seconds, and honestly, we’re kind of on the fence about this part. It would be nice if it faded in and out, or was otherwise a little less distracting, but it did grow on us as we watched the demo.

We love the way this clock celebrates the seven-segment display, and only wish it were much bigger. The STLs and code are available if you want to make one, though they only cover the 7-segment part — the base is made of foam board. Check out the demo and build video after the break.

Would you rather hear the time go by in gentle chimes? Here’s chime clock that uses old hard drive actuators.

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Classic Leica Film Camera Turns Digital

April 10, 2020 by Bryan Cockfield 36 Comments

While there’s still a market for older analog devices such as vinyl records, clocks, and vacuum-tube-powered radio transmitters, a large fraction of these things have become largely digital over the years. There is a certain feel to older devices though which some prefer over their newer, digital counterparts. This is true of the camera world as well, where some still take pictures on film and develop in darkrooms, but if this is too much of a hassle, yet you still appreciate older analog cameras, then this Leica film camera converted to digital might just attract your focus.

This modification comes in two varieties for users with slightly different preferences. One uses a Sony NEX-5 sensor which clips onto the camera and preserves almost all of the inner workings, and the aesthetic, of the original. This sensor isn’t full-frame though, so if that’s a requirement the second option is one with an A7 sensor which requires extensive camera modification (but still preserves the original rangefinder, an almost $700 part even today). Each one has taken care of all of the new digital workings without a screen, with the original film advance, shutters, and other HIDs of their time modified for the new digital world.

The finish of these cameras is exceptional, with every detail considered. The plans aren’t open source, but we have a hard time taking issue with that for the artistry this particular build. This is a modification done to a lot of cameras, but seldom with so much attention paid to the “feel” of the original camera.

Thanks to [Johannes] for the tip!