The Most Immersive Pinball Machine: Project Supernova

Over at [Truthlabs], a 30 year old pinball machine was diagnosed with a major flaw in its game design: It could only entertain one person at a time. [Dan] and his colleagues set out to change this, transforming the ol’ pinball legend “Firepower” into a spectacular, immersive gaming experience worthy of the 21st century.

A major limitation they wanted to overcome was screen size. A projector mounted to the ceiling should turn the entire wall behind the machine into a massive 15-foot playfield for anyone in the room to enjoy.

 

With so much space to fill, the team assembled a visual concept tailored to blend seamlessly with the original storyline of the arcade classic, studying the machine’s artwork and digging deep into the sci-fi archives. They then translated their ideas into 3D graphics utilizing Cinema4D and WebGL along with the usual designer’s toolbox. Lasers and explosions were added, ready to be triggered by game interactions on the machine.

pinnball-ocr-comp

To hook the augmentation into the pinball machine’s own game progress, they elaborated an elegant solution, incorporating OpenCV and OCR, to read all five of the machine’s 7 segment displays from a single webcam. An Arduino inside the machine taps into the numerous mechanical switches and indicator lamps, keeping a Node.js server updated about pressed buttons, hits, the “Lange Change” and plunged balls.

The result is the impressive demonstration of both passion and skill you can see in the video below. We really like the custom shader effects. How could we ever play pinball without them?

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Retrotechtacular: Eidophor, an Unknown Widely Used Projector

If you own a video projector, be it a module small enough to fit in a mobile phone or one designed for a cinema screen, the chances are it will have a DLP at its heart. An array of microscopic mirrors on an integrated circuit, the current state of the art in video projection technology.

Perhaps you own an older video projector, or maybe a cheaper new one. If so the chances are it’ll have a small LCD screen doing its work, taking the place of the Kodachrome in something very similar to your grandparents’ slide projector or their grandparents’ magic lantern.

eidophore-patent-image-600pxLCD technology was invented in the 1970s, while DLP was invented at the end of the 1980s. So how did the video projectors that were such a staple of televised spectaculars in the preceding decades work? For that matter, how did NASA project their status displays on the huge screen at Mission Control? Certainly not with CRT technology, even the brightest CRT projectors weren’t up to filling a cinema-sized screen.

The answer came from the Eidophor (Greek: ‘eido’ and ‘phor’, ‘image’ and ‘bearer’), a device invented in the years before World War II by the Swiss physicist Dr. Fritz Fischer and granted a US patent in 1945. It featured a complex vacuum device in which an electron gun painted the video frames as a raster on an oil-covered mirror in the light path of a fairly conventional projector. High-voltage electric charges have the effect of deforming the surface of mineral oils, and it was this effect that was exploited to vary the effectiveness of the mirror as the raster was drawn. An unfortunate side-effect of tracing an oil surface with an electron beam is that a charge will build up on the oil surface, so the entire oil-covered mirror assembly had to rotate within its vacuum enclosure and pass under an electrode which removed any charge build-up.

Eidophor-wikipedia
Eidophor [by Topquark2 CC-BY-SA 3.0]
The resulting machine as seen in this 1952 issue of Popular Science was very large, complex, and expensive to run, but delivered by far the brightest and sharpest projected video available. In a literal sense they painted the backdrop to our culture, as they found a home not only in NASA’s control room but in television studios and at large televised events. This Shirley Bassey performance from the 1960s for example, or the spectacular video light show on this rather poor quality VHS YouTube clip from Seville Expo 1992.

You will probably be unaware of the exact date you last saw an eidophor performance. Quince Imaging tell us their last one was used at the TWA Dome in St Louis in July 2000. Eidophores may have become more compact over the decades but they remained costly to run, and through the 1990s they were suplanted by DLP devices that did substantially the same job with a lot less fuss.

It is not often that a search in the Hackaday archives for a technology returns no results, but the eidophor is one of those cases. Perhaps that is a fitting epitaph for a device that created its own show but never starred in it, that it is only its spectacular performances that live on.

Must-Have Overkill Christmas Tree Lights

The yuletide fire is out, so we’re starting to receive this year’s Christmas hacks. [Chris] sent us his awesome video-mapped tree lighting hack. His project made clever use of a bunch of cool tools, so even if you’re not thinking forward to next December, it’s worth a look. Still images don’t do it justice; check out the video below the break.

The end result is an addressable string of WS2812B LEDs connected up to a Raspberry Pi Zero that can display a video image even though it’s wrapped around a roughly cone-shaped (pine) object. But this is actually more impressive than you’d think at first; how would you map a flat image to a string of LEDs wrapped around a tree?

[Chris]’s solution was to write a routine that lit up the LEDs in a unique pattern and then detected them using OpenCV and a webcam, making the mapping directly. He then samples images from a video at exactly the points where the pixels are located on the tree, and sends this data out to the LEDs.

The basic framework here should transform fairly easily into a generic image-mapping procedure with randomly located LEDs, so we think it’s a hack that’ll outlast the season. And because it runs on the Pi Zero, everything is in Python so it’d be a good project for beginners to replicate. However, the code section on the project page still lists it as coming soon. We hope so!

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Mineable Minecraft block

At Hack A Day, we’re pretty big Minecraft fans so you can imagine our interest when we saw [Ben Purdy]’s real-life Minecraft block. The build uses a projector system to display a block onto a cardboard box and reacts to being ‘mined’ just like in the game.

Block animation is handled by a piezo sensor, an Arduino and a Processing sketch. From earlier posts on [Ben’s] blog, we’re going to guess that he used the keystone video projection library his own solution to map the Minecraft block onto the cardboard box. Animation is handled just as in Minecraft – overlaying the breaking animation onto the block and adding some particle effects.

We’ve seen a few Minecraft hacks before, like using it as a 3D design tool, and connecting your redstone CPU to the outside world. [Ben]’s build follows in the tradition of its forebears and is something we really want to try out. Check out the demos after the break.

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