A Daylight-Readable Bar Graph Display in the 70s Wasn’t Cheap

The driver board with display attached; the row of lamps is visible on the right hand side.

LEDs weren’t always an easy solution to displays and indicators. The fine folks at [Industrial Alchemy] shared pictures of a device that shows what kind of effort and cost went into making a high brightness bar graph display in the 70s, back when LEDs were both expensive and not particularly bright. There are no strange materials or methods involved in making the display daylight-readable, but it’s a peek at how solving problems we take for granted today sometimes took a lot of expense and effort.

The display is a row of 28 small incandescent bulbs, mounted in a PCB and housed in a machined aluminum frame. Holes through which to view the bulbs are on both the top and front of the metal housing, which allows the unit to be mounted in different orientations. It was made as a swappable module, its 56 machined gold pins mate to sockets on the driver board. The driver board itself consists of 14 LM119 dual comparators, each of which controls two bulbs on the display.

An example of a Wamco minitron bar graph display. Each window contains an incandescent filament. [Source: industrialalchemy.org]
[Industrial Alchemy] believes that the display unit itself may have been a bit of a hack in its own way. Based on the pin spacing and dimensions of the driver board, they feel that it was probably designed to host a row of modular units known as the Wamco minitron bar graph display. An example is pictured here; they resembled DIP chips and could be stacked side-by-side to make a display of any length. Each window contained an incandescent filament in a reflective well, and each light could be individually controlled.

These minitron bar graph units could only be viewed from the top, and were apparently high in cost and low in availability. Getting around these limitations may have been worth creating this compatible unit despite the work involved.

Display technology has taken many different turns over the years, and you can see examples of many of them in one place in the Circus Clock, which tells the time with a different technology for each digit: a nixie, a numitron, a 7-segment thyratron tube, a VFD, an LED dot display, and a rear projection display.

The Naughty AIs That Gamed The System

Artificial intelligence (AI) is undergoing somewhat of a renaissance in the last few years. There’s been plenty of research into neural networks and other technologies, often based around teaching an AI system to achieve certain goals or targets. However, this method of training is fraught with danger, because just like in the movies – the computer doesn’t always play fair.

It’s often very much a case of the AI doing exactly what it’s told, rather than exactly what you intended. Like a devious child who will gladly go to bed in the literal sense, but will not actually sleep, this can cause unexpected, and often quite hilarious results. [Victoria] has created a master list of scholarly references regarding exactly this.

The list spans a wide range of cases. There’s the amusing evolutionary algorithm designed to create creatures capable of high-speed movement, which merely spawned very tall creatures that generated these speeds by falling over. More worryingly, there’s the AI trained to identify toxic and edible mushrooms, which simply picked up on the fact that it was presented with the two types in alternating order. This ended up being an unreliable model in the real world. Similarly, the model designed to assess malignancy of skin cancers determined that lesions photographed with rulers for scale were more likely to be cancerous.

[Victoria] refers to this as “specification gaming”. One can draw parallels to classic sci-fi stories around the “Laws of Robotics”, where robots take such laws to their literal extremes, often causing great harm in the process. It’s an interesting discussion of the difficulty in training artificially intelligent systems to achieve their set goals without undesirable side effects.

We’ve seen plenty of work in this area before – like this use of evolutionary algorithms in circuit design.

Hackaday Links: The Eleventh Day Of The Eleventh Month, 2018

For the better part of the last five years, the Great War Channel on YouTube has been covering the events of the Great War, week by week, exactly 100 years later. It’s hundreds of episodes designed for history buffs, and quite literally one of the most educational channels on YouTube. It’s the eleventh day of the eleventh month of the eighteenth year, which means the folks behind the Great War Channel are probably taking a well-deserved vacation. If you haven’t heard of this channel, it might be a good time to check it out.

Ikea is now selling NFC locks. [Mike] wrote in to tell us he found the new ROTHULT drawer deadbolts for $18 at Ikea. No, these aren’t meant for your front door, they’re meant for file cabinets. That’s a different threat model, and no lock is ever completely secure. However, there are some interesting electronics. You get a lock powered by three AAA batteries and two NFC cards for $18. Can’t wait for the teardown.

The biggest news from the United States this week is big. People gathered in the streets. Millions made sure their voices were heard. Journalists were cut down for asking questions. This is a week that will go down in history. The McRib is back for a limited time. It’s just a reconstituted pork patty, pickles, onions, and sauce on a hoagie roll, but there’s more to the McRib than you would think. McDonalds only releases the McRib when the price of pork is low, and in late October, pork belly futures hit their lowest price since the last time the McRib came to town. This has led some to claim the McRib is just a second lever for McDonalds in an arbitrage play on the price of pork. McDonalds is always buying pork futures, the theory goes, and when it looks like they’re going to lose money, McDonalds simply turns on the McRib production line, pushing pork consumption up, and netting McDonalds a tidy profit. With the volume you’re looking at, McDonalds will never lose money by betting on pork.

You can turn anything into a quadcopter. A dead cat? Yes, it’s been done. How about a quartet of box fans? That’s what the folks at Flite Test did, and while the completed article was wobbly and didn’t survive its first crash, it was a quadcopter made out of box fans.

Belt Up With A Redundant Car Part

The toothed belt that turns the camshaft in synchronization with the crankshaft on many motor vehicle engines is something of an under-appreciated component. Unless you are unlucky enough to ave had one fail and destroy your engine, it’s probably something you’ve never given a second thought to outside of periodic service intervals.

For something to perform such a task over so many thousands of miles of motoring it must be made of pretty strong stuff. Even when a belt is life-expired it is still in good physical shape, and [Crispyjones] saw the potential in a used Subaru belt to make a different type of belt. After keeping his engine in sync for so long it would serve no less vital a purpose, and keep his pants from falling down.

You can of course buy the hardware for a belt from a decent crafting store, but he chose to recycle a buckle from a worn-out leather belt. Cleaning the timing belt and cutting it carefully so that the Subaru logo would be on show to the outside world in the finished article, he secured it round the buckle with some epoxy glue and a bit of stitching. The original leather retaining loop is not really appropriate, so one is fashioned from wire. Finally we see the process for measuring where the holes should be placed, followed by their creation with a hole punch.

Hackaday isn’t a crafting site, so we don’t often feature projects like this one. But the humble timing belt is a component that we’ve probably all replaced and thrown away more than once without really thinking what the properties of the thing we’re throwing away are. So we like this relatively simple project for its re-use of something few of us would otherwise keep, as well as for its delivering rather a cool belt. We’ve featured plenty of cambelts here doing their traditional job, but this is the first time we’ve had one as an item of clothing. We’ll leave you with a glimpse of a future without cambelts at all.

3D-Printer Extrudes Paper Pulp Instead of Plastic

We’ve seen all sorts of 3D-printers on these pages before. From the small to the large, Cartesians and deltas, and printers that can squeeze out plastic, metal, and even concrete. But this appears to be the first time we’ve ever featured a paper-pulp extruding 3D-printer.

It’s fair to ask why the world would need such a thing, and its creator, [Beer Holthuis], has an obvious answer: the world has a lot of waste paper. Like 80 kg per person per year. Thankfully at least some of that is recycled, but that still leaves a lot of raw material that [Beer] wanted to put to work. Build details on the printer are sparse, but from the photos and the video below it seems clear how it all went together. A simple X-Y-Z gantry moves a nozzle over the build platform. The nozzle, an order of magnitude or two larger than the nozzles most of us are used to, is connected to an extruder by a plastic hose. The extruder appears to be tube with a stepper-driven screw that lowers a ram down onto the pulp, squeezing it into the hose. [Beer] notes that the pulp is mixed with a bit of “natural binder” to allow the extruded pulp to keep its shape. We found the extrusion process to be just a wee bit repulsive to watch, but fascinating nonetheless, and the items he’s creating are certainly striking in appearance.

This may be the first pulp printer to grace our pages, but it’s not the first pulp hack we’ve featured. Pulp turns out to be a great material to keep your neighbors happy and even makes a dandy fuel.

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Kinect Visualizer Demo Gives Winamp a Run for Its Money

Winamp eat your heart out, because thanks to the Microsoft Kinect in the hands of [Samarth] there’s a new way to make your screen dance along with you. He created a music visualizer demo that takes advantage of the 3D depth camera on Kinect by outputting a fun pixelated silhouette and color changing strobe. When there are big high-hat hits or bass thumps the camera feed reacts accordingly (as any good visualizer would). He even uploaded his code for the project just in case anyone would like to take a look at it.

The visualizer utilizes the OpenKinect-Processing library which has provided the backbone to many other similar Kinect art projects. It was specifically created to provide a quicker way for coders to access the raw color and depth data output by Kinect. It’s creator, Daniel Shiffman, has posted a number of tutorials to aid anyone looking to create their own real-time animations as well.

The visualizer demo (see video below) was created as part of Maker Faire Hyderabad which is happening over the weekend. The expo is the city’s first Maker Faire and is set to feature over 200 maker exhibits across multiple disciplines. It’s always great to see maker communities outside of the ones that are closest to you geographically speaking, so hopefully we’ll see many more like [Samarth] taking part in more maker events in the future.

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A Fleet of Pressure Washers Powers This Interactive Public Fountain

Public art installations can be cool. Adding in audience interactivity bumps up the coolness factor a bit. Throw civic pride, dancing jets of water, music, and lights into the project, and you get this very cool pressure washer powered musical fountain.

The exhibit that [Niklas Roy] came up with is called Wasserorgel, or “water organ”, an apt name for the creation. Built as part of a celebration of industry in Germany, the display was built in the small town of Winnenden, home to Kärcher, a cleaning equipment company best known for their line of pressure washers in the distinctive yellow cases. Eight of the company’s electric pressure washers were featured in the Wasserorgel, which shot streams of water and played notes in response to passersby tickling the sturdy and waterproof 3D-printed keyboard. The show was managed by an Arduino with a MIDI shield, which controlled the pressure washers via solid state relays and even accepted input from an anemometer to shut down the show if it got too windy, lest the nearby [Frau Dimitrakudi] be dampened.

The video below shows how engaging the Wasserorgel was during its weeks-long run in the town market square; there’s also one in German with build details. And while we can’t recall seeing pressure washers in public art before, we do remember one being used as the basis of a DIY water-jet cutter.

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